Google Git
Sign in
go / gollvm / 6604938f0030f82ed816d53d3f8c413e02ae3dab / . / llvm-gofrontend / go-llvm.cpp
blob: 5b94deb39a16494a3157240da49855159e41568d [file] [log] [blame]
//===-- go-llvm.cpp - LLVM implementation of 'Backend' -------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Methods for class Llvm_backend, a subclass of the gofrontend class
// Backend, with LLVM-specific implementation methods.
//
//===----------------------------------------------------------------------===//
#include "go-llvm.h"
#include "go-llvm-builtins.h"
#include "backend.h"
#include "go-c.h"
#include "go-system.h"
#include "go-llvm-linemap.h"
#include "go-llvm-dibuildhelper.h"
#include "go-llvm-cabi-oracle.h"
#include "go-llvm-irbuilders.h"
#include "gogo.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Support/FileSystem.h"
Llvm_backend::Llvm_backend(llvm::LLVMContext &context,
llvm::Module *module,
Llvm_linemap *linemap)
: TypeManager(context, llvm::CallingConv::X86_64_SysV)
, context_(context)
, module_(module)
, datalayout_(module ? &module->getDataLayout() : nullptr)
, nbuilder_(this)
, diCompileUnit_(nullptr)
, linemap_(linemap)
, addressSpace_(0)
, traceLevel_(0)
, checkIntegrity_(true)
, createDebugMetaData_(true)
, exportDataStarted_(false)
, exportDataFinalized_(false)
, errorCount_(0u)
, compositeSizeThreshold_(8u) // TODO: adjust later to larger value
, TLI_(nullptr)
, builtinTable_(new BuiltinTable(typeManager(), false))
, errorFunction_(nullptr)
, personalityFunction_(nullptr)
{
// If nobody passed in a linemap, create one for internal use (unit testing)
if (!linemap_) {
ownLinemap_.reset(new Llvm_linemap());
linemap_ = ownLinemap_.get();
}
// Similarly for the LLVM module (unit testing)
if (!module_) {
ownModule_.reset(new llvm::Module("gomodule", context));
ownModule_->setTargetTriple("x86_64-unknown-linux-gnu");
ownModule_->setDataLayout("e-m:e-i64:64-f80:128-n8:16:32:64-S128");
module_ = ownModule_.get();
}
datalayout_ = &module_->getDataLayout();
// Reuse the error function as the value for error_expression
errorExpression_ = nbuilder_.mkError(errorType());
// We now have the necessary bits to finish initialization of the
// type manager.
initializeTypeManager(errorExpression(),
datalayout_,
nameTags());
// Create and record an error function. By marking it as varargs this will
// avoid any collisions with things that the front end might create, since
// Go varargs is handled/lowered entirely by the front end.
llvm::SmallVector<llvm::Type *, 1> elems(0);
elems.push_back(llvmPtrType());
const bool isVarargs = true;
llvm::FunctionType *eft = llvm::FunctionType::get(
llvm::Type::getVoidTy(context_), elems, isVarargs);
llvm::GlobalValue::LinkageTypes plinkage = llvm::GlobalValue::ExternalLinkage;
llvm::Function *ef = llvm::Function::Create(eft, plinkage, "", module_);
errorFunction_.reset(new Bfunction(ef, makeAuxFcnType(eft), "", "",
Location(), typeManager()));
// Error statement.
errorStatement_ = nbuilder_.mkErrorStmt();
// Error variable.
Location loc;
errorVariable_.reset(
new Bvariable(errorType(), loc, "", ErrorVar, false, nullptr));
// Initialize machinery for builtins
builtinTable_->defineAllBuiltins();
}
Llvm_backend::~Llvm_backend() {
for (auto &kv : valueVarMap_)
delete kv.second;
for (auto &bfcn : functions_)
delete bfcn;
}
llvm::DICompileUnit *Llvm_backend::getDICompUnit()
{
if (!createDebugMetaData_)
return nullptr;
if (diCompileUnit_ || !createDebugMetaData_)
return diCompileUnit_;
// Create debug info builder
assert(dibuilder_.get() == nullptr);
dibuilder_.reset(new llvm::DIBuilder(*module_));
// Create compile unit
llvm::SmallString<256> currentDir;
llvm::sys::fs::current_path(currentDir);
auto primaryFile =
dibuilder_->createFile(linemap_->get_initial_file(), currentDir);
bool isOptimized = true;
std::string compileFlags; // FIXME
unsigned runtimeVersion = 0; // not sure what would be for Go
diCompileUnit_ =
dibuilder_->createCompileUnit(llvm::dwarf::DW_LANG_Go, primaryFile,
"llvm-goparse", isOptimized,
compileFlags, runtimeVersion);
return diCompileUnit_;
}
TypeManager *Llvm_backend::typeManager() const {
const TypeManager *tm = this;
return const_cast<TypeManager*>(tm);
}
void Llvm_backend::setTraceLevel(unsigned level)
{
traceLevel_ = level;
setTypeManagerTraceLevel(level);
}
void
Llvm_backend::verifyModule()
{
bool broken = llvm::verifyModule(module(), &llvm::dbgs());
assert(!broken && "Module not well-formed.");
}
void
Llvm_backend::dumpModule()
{
module().dump();
}
void Llvm_backend::dumpExpr(Bexpression *e)
{
if (e) {
e->srcDump(linemap_);
TreeIntegCtl ctl(DumpPointers, ReportRepairableSharing, BatchMode);
auto p = checkTreeIntegrity(e, ctl);
if (p.first)
std::cerr << p.second;
}
}
void Llvm_backend::dumpStmt(Bstatement *s)
{
if (s) {
s->srcDump(linemap_);
TreeIntegCtl ctl(DumpPointers, ReportRepairableSharing, BatchMode);
auto p = checkTreeIntegrity(s, ctl);
if (p.first)
std::cerr << p.second;
}
}
void Llvm_backend::dumpVar(Bvariable *v)
{
if (v)
v->srcDump(linemap_);
}
std::pair<bool, std::string>
Llvm_backend::checkTreeIntegrity(Bnode *n, TreeIntegCtl control)
{
Llvm_backend *be = const_cast<Llvm_backend *>(this);
IntegrityVisitor iv(be, control);
bool rval = iv.examine(n);
return std::make_pair(rval, iv.msg());
}
void Llvm_backend::disableIntegrityChecks()
{
checkIntegrity_ = false;
nodeBuilder().setIntegrityChecks(false);
}
void Llvm_backend::enforceTreeIntegrity(Bnode *n)
{
Llvm_backend *be = const_cast<Llvm_backend *>(this);
TreeIntegCtl control(DumpPointers, DontReportRepairableSharing, BatchMode);
IntegrityVisitor iv(be, control);
bool res = iv.examine(n);
if (!res && checkIntegrity_) {
std::cerr << iv.msg() << "\n";
assert(false);
}
}
Btype *Llvm_backend::error_type() {
errorCount_++;
return errorType();
}
Btype *Llvm_backend::void_type() { return voidType(); }
Btype *Llvm_backend::bool_type() { return boolType(); }
// Get an unnamed float type.
Btype *Llvm_backend::float_type(int bits)
{
return floatType(bits);
}
Btype *Llvm_backend::integer_type(bool is_unsigned, int bits)
{
return integerType(is_unsigned, bits);
}
Btype *Llvm_backend::struct_type(const std::vector<Btyped_identifier> &fields)
{
return structType(fields);
}
// Create a placeholder for a struct type.
Btype *Llvm_backend::placeholder_struct_type(const std::string &name,
Location location)
{
return placeholderStructType(name, location);
}
Btype *Llvm_backend::complex_type(int bits) {
return complexType(bits);
}
// Get a pointer type.
Btype *Llvm_backend::pointer_type(Btype *toType)
{
return pointerType(toType);
}
Btype *Llvm_backend::placeholder_pointer_type(const std::string &name,
Location location, bool forfunc)
{
return placeholderPointerType(name, location, forfunc);
}
// Make a function type.
Btype *
Llvm_backend::function_type(const Btyped_identifier &receiver,
const std::vector<Btyped_identifier> &parameters,
const std::vector<Btyped_identifier> &results,
Btype *result_struct, Location loc) {
bool followsCabi = true;
return functionType(receiver, parameters, results,
result_struct, followsCabi, loc);
}
Btype *Llvm_backend::array_type(Btype *elemType, Bexpression *length)
{
return arrayType(elemType, length);
}
Btype *Llvm_backend::placeholder_array_type(const std::string &name,
Location location)
{
return placeholderArrayType(name, location);
}
bool Llvm_backend::set_placeholder_pointer_type(Btype *placeholder,
Btype *to_type)
{
return setPlaceholderPointerType(placeholder, to_type);
}
bool Llvm_backend::set_placeholder_function_type(Btype *placeholder,
Btype *ft) {
return setPlaceholderPointerType(placeholder, ft);
}
bool
Llvm_backend::set_placeholder_struct_type(Btype *placeholder,
const std::vector<Btyped_identifier> &fields)
{
return setPlaceholderStructType(placeholder, fields);
}
// Fill in the components of a placeholder array type.
bool Llvm_backend::set_placeholder_array_type(Btype *placeholder,
Btype *element_btype,
Bexpression *length) {
return setPlaceholderArrayType(placeholder, element_btype, length);
}
Btype *Llvm_backend::named_type(const std::string &name,
Btype *btype,
Location location)
{
return namedType(name, btype, location);
}
Btype *Llvm_backend::circular_pointer_type(Btype *placeholder, bool isf) {
return circularPointerType(placeholder, isf);
}
bool Llvm_backend::is_circular_pointer_type(Btype *btype) {
return isCircularPointerType(btype);
}
int64_t Llvm_backend::type_size(Btype *btype) {
return typeSize(btype);
}
int64_t Llvm_backend::type_alignment(Btype *btype) {
return typeAlignment(btype);
}
int64_t Llvm_backend::type_field_alignment(Btype *btype)
{
return typeFieldAlignment(btype);
}
int64_t Llvm_backend::type_field_offset(Btype *btype, size_t index)
{
return typeFieldOffset(btype, index);
}
llvm::Function *Llvm_backend::personalityFunction()
{
if (personalityFunction_)
return personalityFunction_;
llvm::FunctionType *pft = personalityFunctionType();
llvm::GlobalValue::LinkageTypes plinkage = llvm::GlobalValue::ExternalLinkage;
const char *pfn = "__gccgo_personality_v0";
personalityFunction_ =
llvm::Function::Create(pft, plinkage, pfn, module_);
return personalityFunction_;
}
Bfunction *Llvm_backend::defineBuiltinFcn(const std::string &name,
llvm::Function *fcn)
{
llvm::PointerType *llpft =
llvm::cast<llvm::PointerType>(fcn->getType());
llvm::FunctionType *llft =
llvm::cast<llvm::FunctionType>(llpft->getElementType());
BFunctionType *fcnType = makeAuxFcnType(llft);
Location pdcl = linemap()->get_predeclared_location();
Bfunction *bfunc = new Bfunction(fcn, fcnType, name, name, pdcl,
typeManager());
return bfunc;
}
// Look up a named built-in function in the current backend implementation.
// Returns NULL if no built-in function by that name exists.
Bfunction *Llvm_backend::lookup_builtin(const std::string &name) {
// Do we have an entry at all for this builtin?
BuiltinEntry *be = builtinTable_->lookup(name);
if (!be)
return nullptr;
// We have an entry -- have we materialized a Bfunction for it yet?
Bfunction *bf = be->bfunction();
if (bf != nullptr)
return bf;
// Materialize a Bfunction for the builtin
if (be->flavor() == BuiltinEntry::IntrinsicBuiltin) {
llvm::SmallVector<llvm::Type *, 8> ltypes;
for (auto &t : be->types())
ltypes.push_back(t->type());
llvm::Function *fcn =
llvm::Intrinsic::getDeclaration(module_, be->intrinsicId(), ltypes);
assert(fcn != nullptr);
bf = defineBuiltinFcn(be->name(), fcn);
} else {
assert(be->flavor() == BuiltinEntry::LibcallBuiltin);
// Create function type.
Btyped_identifier receiver;
std::vector<Btyped_identifier> params;
std::vector<Btyped_identifier> results;
Location bloc(linemap_->get_predeclared_location());
const BuiltinEntryTypeVec &types = be->types();
Btyped_identifier result("ret", types[0], bloc);
results.push_back(result);
for (unsigned idx = 1; idx < types.size(); ++idx)
params.push_back(Btyped_identifier("", types[idx], bloc));
bool followsCabi = false;
Btype *fcnType = functionType(receiver, params, results, nullptr,
followsCabi, bloc);
// Create function
bf = function(fcnType, be->name(), be->name(),
true, false, false, false, false, bloc);
// FIXME: add attributes this function? Such as maybe
// llvm::Attribute::ArgMemOnly, llvm::Attribute::ReadOnly?
// FIXME: once we have a pass manager set up for the back end, we'll
// want to turn on this code, since it will be helpful to catch
// errors/mistakes. For the time being it can't be turned on (not
// pass manager is set up).
llvm::LibFunc lf = be->libfunc();
if (TLI_ && lf != llvm::LibFunc::NumLibFuncs) {
// Verify that the function is available on this target.
assert(TLI_->has(lf));
// Verify that the name and type we've computer so far matches up
// with how LLVM views the routine. For example, if we are trying
// to create a version of memcmp() that takes a single boolean as
// an argument, that's going to be a show-stopper type problem.
assert(TLI_->getLibFunc(*bf->function(), lf));
}
}
be->setBfunction(bf);
return bf;
}
bool Llvm_backend::moduleScopeValue(llvm::Value *val, Btype *btype) const
{
valbtype vbt(std::make_pair(val, btype));
return (valueExprmap_.find(vbt) != valueExprmap_.end());
}
Bexpression *Llvm_backend::makeGlobalExpression(Bexpression *expr,
llvm::Value *val,
Btype *btype,
Location location) {
assert(! llvm::isa<llvm::Instruction>(val));
valbtype vbt(std::make_pair(val, btype));
auto it = valueExprmap_.find(vbt);
if (it != valueExprmap_.end()) {
nbuilder_.freeExpr(expr);
return it->second;
}
valueExprmap_[vbt] = expr;
return expr;
}
// Return the zero value for a type.
Bexpression *Llvm_backend::zero_expression(Btype *btype) {
if (btype == errorType())
return errorExpression();
llvm::Value *zeroval = llvm::Constant::getNullValue(btype->type());
Bexpression *cexpr = nbuilder_.mkConst(btype, zeroval);
return makeGlobalExpression(cexpr, zeroval, btype, Location());
}
Bexpression *Llvm_backend::error_expression()
{
errorCount_++;
return errorExpression();
}
Bexpression *Llvm_backend::nil_pointer_expression()
{
// What type should we assign a NIL pointer expression? This
// is something of a head-scratcher. For now use uintptr.
return zero_expression(pointerType(uintPtrType()));
}
Bexpression *Llvm_backend::genCircularConversion(Btype *toType,
Bexpression *expr,
Location loc)
{
llvm::Value *val = expr->value();
llvm::Type *llToType = toType->type();
if (val->getType() == llToType)
return expr;
if (expr->varExprPending()) {
llvm::Type *pet = llvm::PointerType::get(expr->btype()->type(),
addressSpace_);
if (val->getType() == pet)
llToType = llvm::PointerType::get(llToType, addressSpace_);
}
std::string tag(namegen("cast"));
LIRBuilder builder(context_, llvm::ConstantFolder());
llvm::Value *bitcast = builder.CreateBitCast(val, llToType, tag);
return nbuilder_.mkConversion(toType, bitcast, expr, loc);
}
Bexpression *Llvm_backend::genLoad(Bexpression *expr,
Btype *btype,
Location loc,
const std::string &tag)
{
// If this is a load from a pointer flagged as being a circular
// type, insert a conversion prior to the load so as to force
// the value to the correct type. This is weird but necessary,
// since the LLVM type system can't accurately model Go circular
// pointer types.
Bexpression *space = expr;
Btype *loadResultType = btype;
Btype *tctyp = circularTypeLoadConversion(expr->btype());
if (tctyp != nullptr) {
space = genCircularConversion(pointer_type(tctyp), expr, loc);
loadResultType = tctyp;
}
llvm::PointerType *llpt =
llvm::cast<llvm::PointerType>(space->value()->getType());
llvm::Type *llrt = llpt->getElementType();
// If this type meets our criteria (composite/aggregate whose
// size is above a certain threshhold) then assume that the
// consumer will want an address (for memcpy) instead of a
// value.
Bexpression *rval = nullptr;
if (! useCopyForLoadStore(llrt)) {
std::string ldname(tag);
ldname += ".ld";
ldname = namegen(ldname);
llvm::Instruction *loadInst = new llvm::LoadInst(space->value(), ldname);
rval = nbuilder_.mkDeref(loadResultType, loadInst, space, loc);
rval->appendInstruction(loadInst);
} else {
rval = nbuilder_.mkDeref(loadResultType, space->value(), space, loc);
}
return rval;
}
// An expression that indirectly references an expression.
Bexpression *Llvm_backend::indirect_expression(Btype *btype,
Bexpression *expr,
bool known_valid,
Location location) {
if (expr == errorExpression() || btype == errorType())
return errorExpression();
assert(expr->btype()->type()->isPointerTy());
const VarContext *vc = nullptr;
if (expr->varExprPending()) {
vc = &expr->varContext();
// handle *&x
if (vc->addrLevel() != 0) {
Bexpression *rval = nbuilder_.mkDeref(btype, expr->value(), expr,
location);
rval->setVarExprPending(vc->lvalue(), vc->addrLevel() - 1);
return rval;
}
}
std::string tag(expr->tag().size() == 0 ? "deref" : expr->tag());
Bexpression *rval = genLoad(expr, btype, location, tag);
if (vc)
rval->setVarExprPending(expr->varContext());
return rval;
}
// Get the address of an expression.
Bexpression *Llvm_backend::address_expression(Bexpression *bexpr,
Location location) {
if (bexpr == errorExpression())
return errorExpression();
// Gofrontend tends to take the address of things that are already
// pointer-like to begin with (for example, C strings and and
// arrays). This presents wrinkles here, since an array type
// in LLVM is already effectively a pointer (you can feed it
// directly into a GEP as opposed to having to take the address of
// it first). Bypass the effects of the address operator if
// this is the case. This is hacky, maybe I can come up with a
// better solution for this issue(?).
if (llvm::isa<llvm::ConstantArray>(bexpr->value()))
return bexpr;
if (bexpr->value()->getType() == stringType()->type() &&
llvm::isa<llvm::Constant>(bexpr->value()))
return bexpr;
// If the value we're trying to take the address of is a composite
// constant, we have to spill it to memory here in order for us to
// take its address.
llvm::Value *val = bexpr->value();
if (bexpr->isConstant()) {
llvm::Constant *cval = llvm::cast<llvm::Constant>(val);
Bvariable *cv = genVarForConstant(cval, bexpr->btype());
val = cv->value();
}
// Create new expression with proper type.
Btype *pt = pointer_type(bexpr->btype());
Bexpression *rval = nbuilder_.mkAddress(pt, val, bexpr, location);
std::string adtag(bexpr->tag());
adtag += ".ad";
rval->setTag(adtag);
const VarContext &vc = bexpr->varContext();
rval->setVarExprPending(vc.lvalue(), vc.addrLevel() + 1);
// Handle circular types
Btype *ctypconv = circularTypeAddrConversion(bexpr->btype());
if (ctypconv != nullptr)
return genCircularConversion(ctypconv, rval, location);
return rval;
}
bool Llvm_backend::exprVectorHasError(const std::vector<Bexpression *> &vals) {
for (auto v : vals)
if (v == errorExpression())
return true;
return false;
}
bool Llvm_backend::stmtVectorHasError(const std::vector<Bstatement *> &stmts)
{
for (auto s : stmts)
if (s == errorStatement())
return true;
return false;
}
Bexpression *Llvm_backend::resolve(Bexpression *expr,
Varexpr_context ctx)
{
if (expr->compositeInitPending())
expr = resolveCompositeInit(expr, nullptr);
if (expr->varExprPending())
expr = resolveVarContext(expr, ctx);
return expr;
}
Bexpression *Llvm_backend::resolveVarContext(Bexpression *expr,
Varexpr_context ctx)
{
if (expr->varExprPending()) {
const VarContext &vc = expr->varContext();
assert(vc.addrLevel() == 0 || vc.addrLevel() == 1);
if (vc.addrLevel() == 1 || vc.lvalue() || ctx == VE_lvalue) {
assert(vc.addrLevel() == 0 || expr->btype()->type()->isPointerTy());
expr->resetVarExprContext();
return expr;
}
Btype *btype = expr->btype();
Bexpression *rval = genLoad(expr, btype, expr->location(), expr->tag());
return rval;
}
return expr;
}
Bvariable *Llvm_backend::genVarForConstant(llvm::Constant *conval,
Btype *type)
{
auto it = valueVarMap_.find(conval);
if (it != valueVarMap_.end())
return it->second;
std::string ctag(namegen("const"));
Bvariable *rv = makeModuleVar(type, ctag, "", Location(),
MV_Constant, MV_DefaultSection,
MV_NotInComdat, MV_DefaultVisibility,
MV_NotExternallyInitialized,
llvm::GlobalValue::PrivateLinkage,
conval, 0);
assert(llvm::isa<llvm::GlobalVariable>(rv->value()));
return rv;
}
llvm::Value *Llvm_backend::genStore(BlockLIRBuilder *builder,
Btype *srcType,
llvm::Type *dstType,
llvm::Value *srcVal,
llvm::Value *dstLoc)
{
// Don't try to emit a store if the value in question is void
// (for example, the return value from a call to a function that
// returns a struct with no fields). In this case just manufacture
// an undef and return it.
if (srcVal->getType()->isVoidTy())
return llvm::UndefValue::get(srcVal->getType());
// Decide whether we want a simple store instruction or a memcpy.
if (! useCopyForLoadStore(srcType)) {
if (srcVal->getType()->isPointerTy()) {
llvm::PointerType *dstpt =
llvm::cast<llvm::PointerType>(dstType);
srcVal = convertForAssignment(srcType, srcVal,
dstpt->getElementType(), builder);
}
// At this point the types should agree
llvm::PointerType *dpt = llvm::cast<llvm::PointerType>(dstType);
assert(srcVal->getType() == dpt->getElementType());
// Create and return store
return builder->CreateStore(srcVal, dstLoc);
}
// destination should be pointer
assert(dstLoc->getType()->isPointerTy());
// memcpy src: handle constant input (we need something addressable
// in order to do a memcpy, not a raw constant value)
if (llvm::isa<llvm::Constant>(srcVal)) {
llvm::Constant *cval = llvm::cast<llvm::Constant>(srcVal);
Bvariable *cvar = genVarForConstant(cval, srcType);
srcVal = cvar->value();
}
assert(srcVal->getType()->isPointerTy());
// number of bytes to copy
uint64_t sz = typeSize(srcType);
// alignment of src expr
unsigned algn = typeAlignment(srcType);
// Q: should we be using memmove here instead?
llvm::CallInst *call = builder->CreateMemCpy(dstLoc, srcVal, sz, algn);
return call;
}
Bexpression *Llvm_backend::genStore(Bfunction *func,
Bexpression *srcExpr,
Bexpression *dstExpr,
Location location)
{
llvm::Function *dummyFcn = errorFunction_->function();
BlockLIRBuilder builder(dummyFcn, this);
Varexpr_context ctx = varContextDisp(srcExpr);
// Resolve pending var exprs and/or composites
Bexpression *valexp = resolve(srcExpr, ctx);
// Call helper to generate instructions
llvm::Value *val = valexp->value();
llvm::Value *dst = dstExpr->value();
llvm::Value *result = genStore(&builder, srcExpr->btype(),
dstExpr->value()->getType(),
val, dst);
// Wrap result in a Bexpression
Binstructions insns(builder.instructions());
Bexpression *rval =
nbuilder_.mkBinaryOp(OPERATOR_EQ, valexp->btype(), result,
dstExpr, valexp, insns, location);
return rval;
}
Bexpression *Llvm_backend::genArrayInit(llvm::ArrayType *llat,
Bexpression *expr,
llvm::Value *storage)
{
Location loc = expr->location();
Btype *btype = expr->btype();
std::vector<Bexpression *> aexprs = nbuilder_.extractChildenAndDestroy(expr);
expr = nullptr;
unsigned nElements = llat->getNumElements();
assert(nElements == aexprs.size());
llvm::Function *dummyFcn = errorFunction_->function();
BlockLIRBuilder builder(dummyFcn, this);
std::vector<Bexpression *> values;
for (unsigned eidx = 0; eidx < nElements; ++eidx) {
// Construct an appropriate GEP
llvm::SmallVector<llvm::Value *, 2> elems(2);
llvm::Value *idxval = llvm::ConstantInt::get(llvmInt32Type(), eidx);
elems[0] = llvm::ConstantInt::get(llvmInt32Type(), 0);
elems[1] = idxval;
std::string tag(namegen("index"));
llvm::Value *gep = builder.CreateGEP(llat, storage, elems, tag);
// Resolve element value if needed
Varexpr_context ctx = varContextDisp(aexprs[eidx]);
Bexpression *valexp = resolve(aexprs[eidx], ctx);
// Store field value into GEP
genStore(&builder, valexp->btype(), gep->getType(),
valexp->value(), gep);
values.push_back(valexp);
}
Binstructions instructions(builder.instructions());
Bexpression *arexp =
nbuilder_.mkComposite(btype, storage, values, instructions, loc);
return arexp;
}
Bexpression *Llvm_backend::genStructInit(llvm::StructType *llst,
Bexpression *expr,
llvm::Value *storage)
{
Location loc = expr->location();
Btype *btype = expr->btype();
std::vector<Bexpression *> fexprs = nbuilder_.extractChildenAndDestroy(expr);
expr = nullptr;
unsigned nFields = llst->getNumElements();
assert(nFields == fexprs.size());
llvm::Function *dummyFcn = errorFunction_->function();
BlockLIRBuilder builder(dummyFcn, this);
std::vector<Bexpression *> values;
for (unsigned fidx = 0; fidx < nFields; ++fidx) {
Bexpression *fieldValExpr = fexprs[fidx];
assert(fieldValExpr);
Varexpr_context ctx = varContextDisp(fieldValExpr);
Bexpression *valexp = resolve(fieldValExpr, ctx);
// Create GEP
assert(fidx < llst->getNumElements());
std::string tag(namegen("field"));
llvm::Value *gep =
builder.CreateConstInBoundsGEP2_32(llst, storage,
0, fidx, tag);
// Store field value into GEP
genStore(&builder, valexp->btype(), gep->getType(),
valexp->value(), gep);
values.push_back(valexp);
}
Binstructions instructions(builder.instructions());
Bexpression *structexp =
nbuilder_.mkComposite(btype, storage, values, instructions, loc);
return structexp;
}
Bexpression *Llvm_backend::resolveCompositeInit(Bexpression *expr,
llvm::Value *storage)
{
assert(expr != errorExpression());
bool setPending = false;
Bvariable *tvar = nullptr;
if (!storage) {
std::string tname(namegen("tmp"));
tvar = nbuilder_.mkTempVar(expr->btype(), expr->location(), tname);
assert(tvar != errorVariable_.get());
storage = tvar->value();
setPending = true;
}
// Call separate helper depending on array or struct
llvm::Type *llt = expr->btype()->type();
assert(llt->isStructTy() || llt->isArrayTy());
Bexpression *rval = nullptr;
if (llt->isStructTy()) {
llvm::StructType *llst = llvm::cast<llvm::StructType>(llt);
rval = genStructInit(llst, expr, storage);
} else {
llvm::ArrayType *llat = llvm::cast<llvm::ArrayType>(llt);
rval = genArrayInit(llat, expr, storage);
}
if (setPending) {
rval->setVarExprPending(false, 0);
tvar->setInitializerExpr(rval);
}
return rval;
}
Varexpr_context Llvm_backend::varContextDisp(Bexpression *varexp)
{
if (useCopyForLoadStore(varexp->btype()))
return VE_lvalue;
return VE_rvalue;
}
// Create a temporary variable holding the value of EXPR.
// Return the variable and the assignment statement (to be
// attached to some node).
std::pair<Bvariable*, Bstatement*>
Llvm_backend::makeTempVar(Bexpression *expr, Location location) {
assert(expr);
std::string tname(namegen("tmp"));
Bvariable *var = nbuilder_.mkTempVar(expr->btype(), location, tname);
assert(var != errorVariable_.get());
Bfunction *dummyFcn = errorFunction_.get();
Bstatement *init = makeInitStatement(dummyFcn, var, expr);
assert(init != errorStatement_);
return std::make_pair(var, init);
}
// An expression that references a variable.
Bexpression *Llvm_backend::var_expression(Bvariable *var,
Varexpr_context in_lvalue_pos,
Location location) {
if (var == errorVariable_.get())
return errorExpression();
Bexpression *varexp = nbuilder_.mkVar(var, location);
varexp->setTag(var->name().c_str());
varexp->setVarExprPending(in_lvalue_pos == VE_lvalue, 0);
return varexp;
}
// Return an expression that declares a constant named NAME with the
// constant value VAL in BTYPE.
Bexpression *Llvm_backend::named_constant_expression(Btype *btype,
const std::string &name,
Bexpression *val,
Location location) {
if (btype == errorType() || val == errorExpression())
return errorExpression();
// FIXME: declare named read-only variable with initial value 'val'
return val;
}
template <typename wideint_t>
wideint_t checked_convert_mpz_to_int(mpz_t value) {
// See http://gmplib.org/manual/Integer-Import-and-Export.html for an
// explanation of this formula
size_t numbits = 8 * sizeof(wideint_t);
size_t count = (mpz_sizeinbase(value, 2) + numbits - 1) / numbits;
// frontend should have insured this already
assert(count <= 2);
count = 2;
wideint_t receive[2];
receive[0] = 0;
receive[1] = 0;
mpz_export(&receive[0], &count, -1, sizeof(wideint_t), 0, 0, value);
// frontend should have insured this already
assert(receive[1] == 0);
wideint_t rval = receive[0];
if (mpz_sgn(value) < 0)
rval = -rval;
return rval;
}
// Return a typed value as a constant integer.
Bexpression *Llvm_backend::integer_constant_expression(Btype *btype,
mpz_t mpz_val) {
if (btype == errorType())
return errorExpression();
assert(btype->type()->isIntegerTy());
// Force mpz_val into either into uint64_t or int64_t depending on
// whether btype was declared as signed or unsigned.
//
// Q: better to use APInt here?
Bexpression *rval;
BIntegerType *bit = btype->castToBIntegerType();
if (bit->isUnsigned()) {
uint64_t val = checked_convert_mpz_to_int<uint64_t>(mpz_val);
assert(llvm::ConstantInt::isValueValidForType(btype->type(), val));
llvm::Constant *lval = llvm::ConstantInt::get(btype->type(), val);
Bexpression *bconst = nbuilder_.mkConst(btype, lval);
return makeGlobalExpression(bconst, lval, btype, Location());
} else {
int64_t val = checked_convert_mpz_to_int<int64_t>(mpz_val);
assert(llvm::ConstantInt::isValueValidForType(btype->type(), val));
llvm::Constant *lval = llvm::ConstantInt::getSigned(btype->type(), val);
Bexpression *bconst = nbuilder_.mkConst(btype, lval);
return makeGlobalExpression(bconst, lval, btype, Location());
}
return rval;
}
// Return a typed value as a constant floating-point number.
Bexpression *Llvm_backend::float_constant_expression(Btype *btype, mpfr_t val) {
if (btype == errorType())
return errorExpression();
// Force the mpfr value into float, double, or APFloat as appropriate.
//
// Note: at the moment there is no way to create an APFloat from a
// "long double" value, so this code takes the unpleasant step of
// converting a quad mfr value from text and then back into APFloat
// from there.
if (btype->type() == llvmFloatType()) {
float fval = mpfr_get_flt(val, GMP_RNDN);
llvm::APFloat apf(fval);
llvm::Constant *fcon = llvm::ConstantFP::get(context_, apf);
Bexpression *bconst = nbuilder_.mkConst(btype, fcon);
return makeGlobalExpression(bconst, fcon, btype, Location());
} else if (btype->type() == llvmDoubleType()) {
double dval = mpfr_get_d(val, GMP_RNDN);
llvm::APFloat apf(dval);
llvm::Constant *fcon = llvm::ConstantFP::get(context_, apf);
Bexpression *bconst = nbuilder_.mkConst(btype, fcon);
return makeGlobalExpression(bconst, fcon, btype, Location());
} else if (btype->type() == llvmLongDoubleType()) {
assert("not yet implemented" && false);
return nullptr;
} else {
return errorExpression();
}
}
// Return a typed real and imaginary value as a constant complex number.
Bexpression *Llvm_backend::complex_constant_expression(Btype *btype,
mpc_t val) {
if (btype == errorType())
return errorExpression();
BComplexType *bct = btype->castToBComplexType();
assert(bct);
llvm::Type *llt = btype->type();
assert(llt->isStructTy());
llvm::StructType *llst = llvm::cast<llvm::StructType>(llt);
assert(llst->getNumElements() == 2);
llvm::Type *llet = llst->getElementType(0);
assert(llet == llst->getElementType(1));
std::vector<Bexpression *> exps;
if (llet == llvmFloatType()) {
float frval = mpfr_get_flt(mpc_realref(val), GMP_RNDN);
float fival = mpfr_get_flt(mpc_imagref(val), GMP_RNDN);
llvm::APFloat apr(frval);
llvm::APFloat api(fival);
llvm::Constant *rcon = llvm::ConstantFP::get(context_, apr);
llvm::Constant *icon = llvm::ConstantFP::get(context_, api);
Btype *bet = floatType(32);
Bexpression *brcon = nbuilder_.mkConst(bet, rcon);
Bexpression *bicon = nbuilder_.mkConst(bet, icon);
exps.push_back(brcon);
exps.push_back(bicon);
} else if (llet == llvmDoubleType()) {
double drval = mpfr_get_d(mpc_realref(val), GMP_RNDN);
double dival = mpfr_get_d(mpc_imagref(val), GMP_RNDN);
llvm::APFloat apr(drval);
llvm::APFloat api(dival);
llvm::Constant *rcon = llvm::ConstantFP::get(context_, apr);
llvm::Constant *icon = llvm::ConstantFP::get(context_, api);
Btype *bet = floatType(64);
Bexpression *brcon = nbuilder_.mkConst(bet, rcon);
Bexpression *bicon = nbuilder_.mkConst(bet, icon);
exps.push_back(brcon);
exps.push_back(bicon);
} else {
assert(false && "unknown complex type");
return nullptr;
}
std::vector<unsigned long> indexes = {0, 1};
return makeConstCompositeExpr(btype, llst, 2, indexes, exps, Location());
}
// Make a constant string expression.
Bexpression *Llvm_backend::string_constant_expression(const std::string &val)
{
if (val.size() == 0) {
llvm::Value *zer = llvm::Constant::getNullValue(stringType()->type());
Bexpression *bconst = nbuilder_.mkConst(stringType(), zer);
return makeGlobalExpression(bconst, zer, stringType(), Location());
}
// Create constant
bool doAddNull = true;
llvm::Constant *scon =
llvm::ConstantDataArray::getString(context_,
llvm::StringRef(val),
doAddNull);
// Return existing const if installed in table already.
auto it = stringConstantMap_.find(scon);
if (it != stringConstantMap_.end())
return it->second;
// New string. Manufacture a module-scope var to hold the constant,
// then install various maps.
Bvariable *svar =
makeModuleVar(makeAuxType(scon->getType()),
"", "", Location(), MV_Constant, MV_DefaultSection,
MV_NotInComdat, MV_DefaultVisibility,
MV_NotExternallyInitialized,
llvm::GlobalValue::PrivateLinkage, scon, 1);
llvm::Constant *varval = llvm::cast<llvm::Constant>(svar->value());
llvm::Constant *bitcast =
llvm::ConstantExpr::getBitCast(varval, stringType()->type());
Bexpression *bconst = nbuilder_.mkConst(stringType(), bitcast);
Bexpression *rval =
makeGlobalExpression(bconst, bitcast, stringType(), Location());
stringConstantMap_[scon] = rval;
return rval;
}
// Make a constant boolean expression.
Bexpression *Llvm_backend::boolean_constant_expression(bool val) {
LIRBuilder builder(context_, llvm::ConstantFolder());
llvm::Value *con = (val ? llvm::ConstantInt::getTrue(context_)
: llvm::ConstantInt::getFalse(context_));
llvm::Value *tobool = builder.CreateZExt(con, bool_type()->type(), "");
Bexpression *bconst = nbuilder_.mkConst(bool_type(), tobool);
return makeGlobalExpression(bconst, tobool, bool_type(), Location());
}
// Return the real part of a complex expression.
Bexpression *Llvm_backend::real_part_expression(Bexpression *bcomplex,
Location location) {
if (bcomplex == errorExpression())
return errorExpression();
if (bcomplex->compositeInitPending())
bcomplex = resolveCompositeInit(bcomplex, nullptr);
// Construct an appropriate GEP
llvm::Type *llt = bcomplex->btype()->type();
assert(llt->isStructTy());
llvm::StructType *llst = llvm::cast<llvm::StructType>(llt);
llvm::Value *cval = bcomplex->value();
llvm::Value *fval;
if (bcomplex->isConstant())
fval = llvm::cast<llvm::Constant>(cval)->getAggregateElement((unsigned int)0);
else
fval = makeFieldGEP(llst, 0, cval);
BComplexType *bct = bcomplex->btype()->castToBComplexType();
assert(bct);
Btype *bft = floatType(bct->bits()/2);
// Wrap result in a Bexpression
Bexpression *rval = nbuilder_.mkStructField(bft, fval, bcomplex,
0, location);
std::string tag(bcomplex->tag());
tag += ".real";
rval->setTag(tag);
// We're done
return rval;
}
// Return the imaginary part of a complex expression.
Bexpression *Llvm_backend::imag_part_expression(Bexpression *bcomplex,
Location location) {
if (bcomplex == errorExpression())
return errorExpression();
if (bcomplex->compositeInitPending())
bcomplex = resolveCompositeInit(bcomplex, nullptr);
// Construct an appropriate GEP
llvm::Type *llt = bcomplex->btype()->type();
assert(llt->isStructTy());
llvm::StructType *llst = llvm::cast<llvm::StructType>(llt);
llvm::Value *cval = bcomplex->value();
llvm::Value *fval;
if (bcomplex->isConstant())
fval = llvm::cast<llvm::Constant>(cval)->getAggregateElement((unsigned int)1);
else
fval = makeFieldGEP(llst, 1, cval);
BComplexType *bct = bcomplex->btype()->castToBComplexType();
assert(bct);
Btype *bft = floatType(bct->bits()/2);
// Wrap result in a Bexpression
Bexpression *rval = nbuilder_.mkStructField(bft, fval, bcomplex,
1, location);
std::string tag(bcomplex->tag());
tag += ".imag";
rval->setTag(tag);
// We're done
return rval;
}
// Make a complex expression given its real and imaginary parts.
Bexpression *Llvm_backend::complex_expression(Bexpression *breal,
Bexpression *bimag,
Location location) {
if (breal == errorExpression() || bimag == errorExpression())
return errorExpression();
assert(breal->btype() == bimag->btype());
BFloatType *bet = breal->btype()->castToBFloatType();
assert(bet);
Btype *bct = complexType(bet->bits()*2);
llvm::Type *llt = bct->type();
assert(llt->isStructTy());
llvm::StructType *llst = llvm::cast<llvm::StructType>(llt);
std::vector<Bexpression *> vals = {breal, bimag};
std::vector<unsigned long> indexes = {0, 1};
// Constant values?
bool isConstant = valuesAreConstant(vals);
if (isConstant)
return makeConstCompositeExpr(bct, llst, 2, indexes, vals, location);
else
return makeDelayedCompositeExpr(bct, llst, 2, indexes, vals, location);
}
// An expression that converts an expression to a different type.
Bexpression *Llvm_backend::convert_expression(Btype *type, Bexpression *expr,
Location location) {
if (type == errorType() || expr == errorExpression())
return errorExpression();
if (expr->btype() == type)
return expr;
// When the frontend casts something to function type, what this
// really means in the LLVM realm is "pointer to function" type.
llvm::Type *toType = type->type();
if (toType->isFunctionTy()) {
type = pointer_type(type);
toType = type->type();
}
// Complex -> complex conversion
if (type->castToBComplexType())
return makeComplexConvertExpr(type, expr, location);
// For composite-init-pending values, materialize a variable now.
if (expr->compositeInitPending()) {
assert(!expr->varExprPending());
expr = resolveCompositeInit(expr, nullptr);
}
llvm::Value *val = expr->value();
assert(val);
llvm::Type *valType = val->getType();
// In the varexpr pending case, decide what to do depending on whether
// the var is in an lvalue or rvalue context. For something like
//
// var y int32
// z = int64(y)
//
// we want to force the load of "y" before converting to int64. For
// an lvalue context, the conversion will be applied to the pointed-to-type
// as well as the value type.
if (expr->varExprPending()) {
bool lvalue = expr->varContext().lvalue();
if (!lvalue) {
expr = resolveVarContext(expr);
val = expr->value();
valType = val->getType();
}
if (lvalue || useCopyForLoadStore(type->type())) {
llvm::Type *pet = llvm::PointerType::get(expr->btype()->type(),
addressSpace_);
if (valType == pet)
toType = llvm::PointerType::get(toType, addressSpace_);
}
}
// Compare types for equality using Btype::equivalent, since we need to
// pick up on differences in the Btype that are not present in the
// LLVM type (for example, uint32 vs int32), and since we want to
// screen out cases where there are different LLVM types as a result
// the use of opaque structs.
if (expr->btype()->equivalent(*type)) {
if (toType == valType)
return expr;
else
return nbuilder_.mkConversion(type, expr->value(), expr, location);
}
LIRBuilder builder(context_, llvm::ConstantFolder());
// Pointer type to pointer-sized-integer type. Comes up when
// converting function pointer to function descriptor (during
// creation of function descriptor vals) or constant array to
// uintptr (as part of GC symbol initializer creation), and in other
// places in FE-generated code (ex: array index checks).
if (valType->isPointerTy() && toType == llvmIntegerType()) {
std::string tname(namegen("pticast"));
llvm::Value *pticast = builder.CreatePtrToInt(val, toType, tname);
return nbuilder_.mkConversion(type, pticast, expr, location);
}
// Pointer-sized-integer type pointer type. This comes up
// in type hash/compare functions.
if (toType->isPointerTy() && valType == llvmIntegerType()) {
std::string tname(namegen("itpcast"));
llvm::Value *itpcast = builder.CreateIntToPtr(val, toType, tname);
return nbuilder_.mkConversion(type, itpcast, expr, location);
}
// For pointer conversions (ex: *int32 => *int64) create an
// appropriate bitcast.
if (valType->isPointerTy() && toType->isPointerTy()) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder.CreateBitCast(val, toType, tag);
return nbuilder_.mkConversion(type, bitcast, expr, location);
}
// Integer-to-integer conversions
if (valType->isIntegerTy() && toType->isIntegerTy()) {
llvm::IntegerType *valIntTyp =
llvm::cast<llvm::IntegerType>(valType);
llvm::IntegerType *toIntTyp =
llvm::cast<llvm::IntegerType>(toType);
unsigned valbits = valIntTyp->getBitWidth();
unsigned tobits = toIntTyp->getBitWidth();
llvm::Value *conv = nullptr;
if (tobits > valbits) {
if (expr->btype()->type() == llvmBoolType() ||
expr->btype()->castToBIntegerType()->isUnsigned())
conv = builder.CreateZExt(val, toType, namegen("zext"));
else
conv = builder.CreateSExt(val, toType, namegen("sext"));
} else {
conv = builder.CreateTrunc(val, toType, namegen("trunc"));
}
return nbuilder_.mkConversion(type, conv, expr, location);
}
// Float -> float conversions
if (toType->isFloatingPointTy() && valType->isFloatingPointTy()) {
llvm::Value *conv = nullptr;
if (toType == llvmFloatType() && valType == llvmDoubleType())
conv = builder.CreateFPTrunc(val, toType, namegen("fptrunc"));
else if (toType == llvmDoubleType() && valType == llvmFloatType())
conv = builder.CreateFPExt(val, toType, namegen("fpext"));
else
assert(0 && "unexpected float type");
return nbuilder_.mkConversion(type, conv, expr, location);
}
// Float -> integer conversions
if (toType->isIntegerTy() && valType->isFloatingPointTy()) {
llvm::Value *conv = nullptr;
if (type->castToBIntegerType()->isUnsigned())
conv = builder.CreateFPToUI(val, toType, namegen("ftoui"));
else
conv = builder.CreateFPToSI(val, toType, namegen("ftosi"));
return nbuilder_.mkConversion(type, conv, expr, location);
}
// Integer -> float conversions
if (toType->isFloatingPointTy() && valType->isIntegerTy()) {
llvm::Value *conv = nullptr;
if (expr->btype()->castToBIntegerType()->isUnsigned())
conv = builder.CreateUIToFP(val, toType, namegen("uitof"));
else
conv = builder.CreateSIToFP(val, toType, namegen("sitof"));
return nbuilder_.mkConversion(type, conv, expr, location);
}
// This case not handled yet. In particular code needs to be
// written to handle signed/unsigned, conversions between scalars
// of various sizes and types.
assert(false && "this flavor of conversion not yet handled");
return expr;
}
Bexpression *Llvm_backend::makeComplexConvertExpr(Btype *type,
Bexpression *expr,
Location location) {
if (expr->btype()->type() == type->type())
return expr;
BComplexType *bct = type->castToBComplexType();
assert(bct);
assert(expr->btype()->castToBComplexType());
Btype *bft = floatType(bct->bits()/2);
// We need to avoid sharing between real part and imag part of the operand.
// Create temp variables and assign operand to the temp variable first.
// TODO: maybe not make temp var if the operand is already a var or constant?
auto p = makeTempVar(expr, location);
Bvariable *var = p.first;
Bstatement *einit = p.second;
Bexpression *vex = nbuilder_.mkVar(var, location);
vex->setVarExprPending(false, 0);
Bexpression *vexr = real_part_expression(vex, location);
Bexpression *vexi = imag_part_expression(vex, location);
// Make the conversion
Bexpression *valr = convert_expression(bft, vexr, location);
Bexpression *vali = convert_expression(bft, vexi, location);
Bexpression *val = complex_expression(valr, vali, location);
// Wrap result and the init statements in a compound expression.
// Currently we can't resolve composite storage for compound
// expression, so we resolve the inner complex expression
// here with another temp variable.
auto p2 = makeTempVar(val, location);
Bvariable *rvar = p2.first;
Bstatement *rinit = p2.second;
Bexpression *rvex = nbuilder_.mkVar(rvar, location);
Bstatement *init = statement_list(std::vector<Bstatement*>{einit, rinit});
return compound_expression(init, rvex, location);
}
// Get the address of a function.
Bexpression *Llvm_backend::function_code_expression(Bfunction *bfunc,
Location location) {
if (bfunc == errorFunction_.get())
return errorExpression();
assert(llvm::isa<llvm::Constant>(bfunc->function()));
// Look up pointer-to-function type
Btype *fpBtype = pointer_type(bfunc->fcnType());
// Create an address-of-function expr
Bexpression *fexpr = nbuilder_.mkFcnAddress(fpBtype, bfunc->function(),
bfunc, location);
return makeGlobalExpression(fexpr, bfunc->function(), fpBtype, location);
}
llvm::Value *Llvm_backend::makePointerOffsetGEP(llvm::PointerType *llpt,
llvm::Value *idxval,
llvm::Value *sptr)
{
LIRBuilder builder(context_, llvm::ConstantFolder());
llvm::SmallVector<llvm::Value *, 1> elems(1);
elems[0] = idxval;
llvm::Value *val = builder.CreateGEP(llpt, sptr, elems, namegen("ptroff"));
return val;
}
llvm::Value *Llvm_backend::makeArrayIndexGEP(llvm::ArrayType *llat,
llvm::Value *idxval,
llvm::Value *sptr)
{
LIRBuilder builder(context_, llvm::ConstantFolder());
llvm::SmallVector<llvm::Value *, 2> elems(2);
elems[0] = llvm::ConstantInt::get(llvmInt32Type(), 0);
elems[1] = idxval;
llvm::Value *val = builder.CreateGEP(llat, sptr, elems, namegen("index"));
return val;
}
llvm::Value *Llvm_backend::makeFieldGEP(llvm::StructType *llst,
unsigned fieldIndex,
llvm::Value *sptr)
{
assert(sptr->getType()->isPointerTy());
LIRBuilder builder(context_, llvm::ConstantFolder());
assert(fieldIndex < llst->getNumElements());
std::string tag(namegen("field"));
llvm::Value *val =
builder.CreateConstInBoundsGEP2_32(llst, sptr, 0, fieldIndex, tag);
return val;
}
// Return an expression for the field at INDEX in BSTRUCT.
Bexpression *Llvm_backend::struct_field_expression(Bexpression *bstruct,
size_t index,
Location location) {
if (bstruct == errorExpression())
return errorExpression();
if (bstruct->compositeInitPending())
bstruct = resolveCompositeInit(bstruct, nullptr);
// Construct an appropriate GEP
llvm::Type *llt = bstruct->btype()->type();
assert(llt->isStructTy());
llvm::StructType *llst = llvm::cast<llvm::StructType>(llt);
llvm::Value *sval = bstruct->value();
llvm::Value *fval;
if (bstruct->isConstant())
fval = llvm::cast<llvm::Constant>(sval)->getAggregateElement(index);
else
fval = makeFieldGEP(llst, index, sval);
Btype *bft = elementTypeByIndex(bstruct->btype(), index);
// Wrap result in a Bexpression
Bexpression *rval = nbuilder_.mkStructField(bft, fval, bstruct,
index, location);
if (bstruct->varExprPending())
rval->setVarExprPending(bstruct->varContext());
std::string tag(bstruct->tag());
tag += ".field";
rval->setTag(tag);
// We're done
return rval;
}
// Return an expression that executes BSTAT before BEXPR.
Bexpression *Llvm_backend::compound_expression(Bstatement *bstat,
Bexpression *bexpr,
Location location) {
if (bstat == errorStatement() || bexpr == errorExpression())
return errorExpression();
// Compound expressions can be used to produce lvalues, so we don't
// want to call resolve() on bexpr here.
Bexpression *rval = nbuilder_.mkCompound(bstat, bexpr, location);
return rval;
}
// Return an expression that executes THEN_EXPR if CONDITION is true, or
// ELSE_EXPR otherwise.
Bexpression *Llvm_backend::conditional_expression(Bfunction *function,
Btype *btype,
Bexpression *condition,
Bexpression *then_expr,
Bexpression *else_expr,
Location location)
{
if (function == errorFunction_.get() ||
btype == errorType() ||
condition == errorExpression() ||
then_expr == errorExpression() ||
else_expr == errorExpression())
return errorExpression();
assert(condition && then_expr);
condition = resolveVarContext(condition);
then_expr = resolve(then_expr);
if (else_expr)
else_expr = resolve(else_expr);
std::vector<Bvariable *> novars;
Bblock *thenBlock = nbuilder_.mkBlock(function, novars, location);
Bblock *elseBlock = nullptr;
Bvariable *tempv = nullptr;
// FIXME: add lifetime intrinsics for temp var below.
Bstatement *thenStmt = nullptr;
if (!btype || then_expr->btype() == void_type())
thenStmt = expression_statement(function, then_expr);
else
tempv = temporary_variable(function, nullptr,
btype, then_expr, false,
location, &thenStmt);
nbuilder_.addStatementToBlock(thenBlock, thenStmt);
if (else_expr) {
Bstatement *elseStmt = nullptr;
elseBlock = nbuilder_.mkBlock(function, novars, location);
if (!btype || else_expr->btype() == void_type()) {
elseStmt = expression_statement(function, else_expr);
} else {
// Capture "else_expr" into temporary. Type needs to agree with
// then_expr if then_expr had non-void type.
if (!tempv) {
tempv = temporary_variable(function, nullptr,
btype, else_expr, false,
location, &elseStmt);
} else {
// Ideally it would be nice to assert that the types are
// identical for if_expr and else_expr, but particularly for
// pointer types we need to allow for some disagreement (ex:
// nil_pointer_expression, which is untyped/polymorphic).
// Assume that the type checking in the call to
// assignment_statement will catch any problems.
Bexpression *varExpr = var_expression(tempv, VE_lvalue, location);
elseStmt = assignment_statement(function, varExpr, else_expr, location);
}
}
nbuilder_.addStatementToBlock(elseBlock, elseStmt);
}
// Wrap up and return the result
Bstatement *ifStmt = if_statement(function, condition,
thenBlock, elseBlock, location);
Bexpression *rval = (tempv ?
var_expression(tempv, VE_rvalue, location) :
nbuilder_.mkVoidValue(void_type()));
Bexpression *result = compound_expression(ifStmt, rval, location);
return result;
}
// Return an expression for the unary operation OP EXPR.
Bexpression *Llvm_backend::unary_expression(Operator op, Bexpression *expr,
Location location) {
if (expr == errorExpression())
return errorExpression();
expr = resolveVarContext(expr);
Btype *bt = expr->btype();
switch (op) {
case OPERATOR_MINUS: {
// FIXME: for floating point zero expr should be -0.0
return binary_expression(OPERATOR_MINUS, zero_expression(bt),
expr, location);
}
case OPERATOR_NOT: {
LIRBuilder builder(context_, llvm::ConstantFolder());
assert(isBooleanType(bt));
// FIXME: is this additional compare-to-zero needed? Or can we be certain
// that the value in question has a single bit set?
Bexpression *bzero = zero_expression(bt);
llvm::Value *cmp =
builder.CreateICmpNE(expr->value(), bzero->value(), namegen("icmp"));
Btype *lbt = makeAuxType(llvmBoolType());
Bexpression *cmpex =
nbuilder_.mkBinaryOp(OPERATOR_EQEQ, lbt, cmp, bzero, expr, location);
llvm::Constant *one = llvm::ConstantInt::get(llvmBoolType(), 1);
llvm::Value *xorex = builder.CreateXor(cmp, one, namegen("xor"));
Bexpression *notex = nbuilder_.mkUnaryOp(op, lbt, xorex, cmpex, location);
Bexpression *tobool = convert_expression(bool_type(), notex, location);
return tobool;
}
case OPERATOR_XOR: {
// ^x bitwise complement is m ^ x with m = "all bits set to 1"
// for unsigned x and m = -1 for signed x
assert(bt->type()->isIntegerTy());
LIRBuilder builder(context_, llvm::ConstantFolder());
llvm::Value *onesval = llvm::Constant::getAllOnesValue(bt->type());
llvm::Value *xorExpr = builder.CreateXor(expr->value(), onesval,
namegen("xor"));
Bexpression *rval = nbuilder_.mkUnaryOp(op, bt, xorExpr, expr, location);
return rval;
break;
}
default:
assert(false && "unexpected unary opcode");
}
return nullptr;
}
static llvm::CmpInst::Predicate compare_op_to_pred(Operator op,
llvm::Type *typ,
bool isUnsigned)
{
bool isFloat = typ->isFloatingPointTy();
if (isFloat) {
switch (op) {
case OPERATOR_EQEQ:
return llvm::CmpInst::Predicate::FCMP_OEQ;
case OPERATOR_NOTEQ:
return llvm::CmpInst::Predicate::FCMP_ONE;
case OPERATOR_LT:
return llvm::CmpInst::Predicate::FCMP_OLT;
case OPERATOR_LE:
return llvm::CmpInst::Predicate::FCMP_OLE;
case OPERATOR_GT:
return llvm::CmpInst::Predicate::FCMP_OGT;
case OPERATOR_GE:
return llvm::CmpInst::Predicate::FCMP_OGE;
default:
break;
}
} else {
switch (op) {
case OPERATOR_EQEQ:
return llvm::CmpInst::Predicate::ICMP_EQ;
case OPERATOR_NOTEQ:
return llvm::CmpInst::Predicate::ICMP_NE;
case OPERATOR_LT:
return (isUnsigned ? llvm::CmpInst::Predicate::ICMP_ULT
: llvm::CmpInst::Predicate::ICMP_SLT);
case OPERATOR_LE:
return (isUnsigned ? llvm::CmpInst::Predicate::ICMP_ULE
: llvm::CmpInst::Predicate::ICMP_SLE);
case OPERATOR_GT:
return (isUnsigned ? llvm::CmpInst::Predicate::ICMP_UGT
: llvm::CmpInst::Predicate::ICMP_SGT);
case OPERATOR_GE:
return (isUnsigned ? llvm::CmpInst::Predicate::ICMP_UGE
: llvm::CmpInst::Predicate::ICMP_SGE);
default:
break;
}
}
assert(false);
return llvm::CmpInst::BAD_ICMP_PREDICATE;
}
std::pair<llvm::Value *, llvm::Value *>
Llvm_backend::convertForBinary(Bexpression *left, Bexpression *right)
{
llvm::Value *leftVal = left->value();
llvm::Value *rightVal = right->value();
std::pair<llvm::Value *, llvm::Value *> rval =
std::make_pair(leftVal, rightVal);
llvm::Type *leftType = leftVal->getType();
llvm::Type *rightType = rightVal->getType();
if (leftType == rightType)
return rval;
// Case 1: nil op X
if (llvm::isa<llvm::ConstantPointerNull>(leftVal) &&
rightType->isPointerTy()) {
BexprLIRBuilder builder(context_, left);
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder.CreateBitCast(leftVal, rightType, tag);
rval.first = bitcast;
return rval;
}
// Case 2: X op nil
if (llvm::isa<llvm::ConstantPointerNull>(rightVal) &&
leftType->isPointerTy()) {
BexprLIRBuilder builder(context_, right);
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder.CreateBitCast(rightVal, leftType, tag);
rval.second = bitcast;
return rval;
}
return rval;
}
// Return an expression for the binary operation LEFT OP RIGHT.
Bexpression *Llvm_backend::binary_expression(Operator op, Bexpression *left,
Bexpression *right,
Location location) {
if (left == errorExpression() || right == errorExpression())
return errorExpression();
Btype *bltype = left->btype();
Btype *brtype = right->btype();
BComplexType *blctype = bltype->castToBComplexType();
BComplexType *brctype = brtype->castToBComplexType();
assert((blctype == nullptr) == (brctype == nullptr));
if (blctype)
return makeComplexBinaryExpr(op, left, right, location);
left = resolveVarContext(left);
right = resolveVarContext(right);
assert(left->value() && right->value());
std::pair<llvm::Value *, llvm::Value *> converted =
convertForBinary(left, right);
llvm::Value *leftVal = converted.first;
llvm::Value *rightVal = converted.second;
llvm::Type *ltype = leftVal->getType();
llvm::Type *rtype = rightVal->getType();
assert(ltype == rtype);
BIntegerType *blitype = bltype->castToBIntegerType();
BIntegerType *britype = brtype->castToBIntegerType();
assert((blitype == nullptr) == (britype == nullptr));
bool isUnsigned = false;
if (blitype) {
if (op == OPERATOR_LSHIFT || op == OPERATOR_RSHIFT)
assert(britype->isUnsigned());
else
assert(blitype->isUnsigned() == britype->isUnsigned());
isUnsigned = blitype->isUnsigned();
}
LIRBuilder builder(context_, llvm::ConstantFolder());
llvm::Value *val = nullptr;
switch (op) {
case OPERATOR_EQEQ:
case OPERATOR_NOTEQ:
case OPERATOR_LT:
case OPERATOR_LE:
case OPERATOR_GT:
case OPERATOR_GE: {
llvm::CmpInst::Predicate pred = compare_op_to_pred(op, ltype, isUnsigned);
if (ltype->isFloatingPointTy())
val = builder.CreateFCmp(pred, leftVal, rightVal, namegen("fcmp"));
else
val = builder.CreateICmp(pred, leftVal, rightVal, namegen("icmp"));
Btype *bcmpt = makeAuxType(llvmBoolType());
// gen compare...
Bexpression *cmpex =
nbuilder_.mkBinaryOp(op, bcmpt, val, left, right, location);
// ... widen to go boolean type
return convert_expression(bool_type(), cmpex, location);
}
case OPERATOR_MINUS: {
if (ltype->isFloatingPointTy())
val = builder.CreateFSub(leftVal, rightVal, namegen("fsub"));
else
val = builder.CreateSub(leftVal, rightVal, namegen("sub"));
break;
}
case OPERATOR_PLUS: {
if (ltype->isFloatingPointTy())
val = builder.CreateFAdd(leftVal, rightVal, namegen("fadd"));
else
val = builder.CreateAdd(leftVal, rightVal, namegen("add"));
break;
}
case OPERATOR_MULT: {
if (ltype->isFloatingPointTy())
val = builder.CreateFMul(leftVal, rightVal, namegen("fmul"));
else
val = builder.CreateMul(leftVal, rightVal, namegen("mul"));
break;
}
case OPERATOR_MOD: {
assert(! ltype->isFloatingPointTy());
if (isUnsigned)
val = builder.CreateURem(leftVal, rightVal, namegen("mod"));
else
val = builder.CreateSRem(leftVal, rightVal, namegen("mod"));
break;
}
case OPERATOR_DIV: {
if (ltype->isFloatingPointTy())
val = builder.CreateFDiv(leftVal, rightVal, namegen("fdiv"));
else if (isUnsigned)
val = builder.CreateUDiv(leftVal, rightVal, namegen("div"));
else
val = builder.CreateSDiv(leftVal, rightVal, namegen("div"));
break;
}
case OPERATOR_OROR:
// Note that the FE will have already expanded out || in a control
// flow context (short circuiting)
// fall through...
case OPERATOR_OR: {
assert(!ltype->isFloatingPointTy());
val = builder.CreateOr(leftVal, rightVal, namegen("ior"));
break;
}
case OPERATOR_BITCLEAR:
// Note that the FE already inserted a complement op to RHS. So
// this is effectively an AND expression.
// fall through...
case OPERATOR_ANDAND:
// Note that the FE will have already expanded out && in a control
// flow context (short circuiting).
// fall through...
case OPERATOR_AND: {
assert(!ltype->isFloatingPointTy());
val = builder.CreateAnd(leftVal, rightVal, namegen("iand"));
break;
}
case OPERATOR_XOR: {
assert(!ltype->isFloatingPointTy() && !rtype->isFloatingPointTy());
val = builder.CreateXor(leftVal, rightVal, namegen("xor"));
break;
}
case OPERATOR_LSHIFT: {
// Note that the FE already inserted conditionals for checking
// large shift amounts. So this can simply lower to a shift
// instruction.
assert(!ltype->isFloatingPointTy() && !rtype->isFloatingPointTy());
val = builder.CreateShl(leftVal, rightVal, namegen("shl"));
break;
}
case OPERATOR_RSHIFT: {
// Note that the FE already inserted conditionals for checking
// large shift amounts. So this can simply lower to a shift
// instruction.
assert(!ltype->isFloatingPointTy() && !rtype->isFloatingPointTy());
if (isUnsigned)
val = builder.CreateLShr(leftVal, rightVal, namegen("shr"));
else
val = builder.CreateAShr(leftVal, rightVal, namegen("shr"));
break;
}
default:
std::cerr << "Op " << op << " unhandled\n";
assert(false);
}
return nbuilder_.mkBinaryOp(op, bltype, val, left, right, location);
}
Bexpression *Llvm_backend::makeComplexBinaryExpr(Operator op, Bexpression *left,
Bexpression *right,
Location location) {
// We need to avoid sharing between real part and imag part of the operand.
// Create temp variables and assign operands to the temp vars first.
// TODO: maybe not make temp var if the operand is already a var or constant?
auto p = makeTempVar(left, location), p2 = makeTempVar(right, location);
Bvariable *lvar = p.first, *rvar = p2.first;
Bstatement *linit = p.second, *rinit = p2.second;
Bexpression *lvex = nbuilder_.mkVar(lvar, location);
lvex->setVarExprPending(false, 0);
Bexpression *rvex = nbuilder_.mkVar(rvar, location);
rvex->setVarExprPending(false, 0);
Bexpression *lr = real_part_expression(lvex, location);
Bexpression *li = imag_part_expression(lvex, location);
Bexpression *rr = real_part_expression(rvex, location);
Bexpression *ri = imag_part_expression(rvex, location);
Bexpression *val;
switch (op) {
case OPERATOR_PLUS:
case OPERATOR_MINUS: {
Bexpression *valr = binary_expression(op, lr, rr, location);
Bexpression *vali = binary_expression(op, li, ri, location);
val = complex_expression(valr, vali, location);
break;
}
case OPERATOR_MULT: {
// (a+bi)*(c+di) = (ac-bd) + (ad+bc)i
Bexpression *ac = binary_expression(OPERATOR_MULT, lr, rr, location);
Bexpression *bd = binary_expression(OPERATOR_MULT, li, ri, location);
Bexpression *ad = binary_expression(OPERATOR_MULT, lr, ri, location);
Bexpression *bc = binary_expression(OPERATOR_MULT, li, rr, location);
Bexpression *valr = binary_expression(OPERATOR_MINUS, ac, bd, location);
Bexpression *vali = binary_expression(OPERATOR_PLUS, ad, bc, location);
val = complex_expression(valr, vali, location);
break;
}
case OPERATOR_EQEQ:
case OPERATOR_NOTEQ: {
Bexpression *cmpr = binary_expression(op, lr, rr, location);
Bexpression *cmpi = binary_expression(op, li, ri, location);
if (op == OPERATOR_EQEQ)
val = binary_expression(OPERATOR_ANDAND, cmpr, cmpi, location);
else
val = binary_expression(OPERATOR_OROR, cmpr, cmpi, location);
Bstatement *init = statement_list(std::vector<Bstatement*>{linit, rinit});
return compound_expression(init, val, location);
}
default:
std::cerr << "Op " << op << " unhandled\n";
assert(false);
}
// Wrap result and the init statements in a compound expression.
// Currently we can't resolve composite storage for compound
// expression, so we resolve the inner complex expression
// here with another temp variable.
auto p3 = makeTempVar(val, location);
Bvariable *vvar = p3.first;
Bstatement *vinit = p3.second;
Bexpression *vvex = nbuilder_.mkVar(vvar, location);
Bstatement *init = statement_list(std::vector<Bstatement*>{linit, rinit, vinit});
return compound_expression(init, vvex, location);
}
bool
Llvm_backend::valuesAreConstant(const std::vector<Bexpression *> &vals)
{
for (auto &val : vals)
if (!val->isConstant())
return false;
return true;
}
// Return an expression that constructs BTYPE with VALS.
Bexpression *Llvm_backend::constructor_expression(
Btype *btype, const std::vector<Bexpression *> &vals, Location location) {
if (btype == errorType() || exprVectorHasError(vals))
return errorExpression();
llvm::Type *llt = btype->type();
assert(llt->isStructTy());
llvm::StructType *llst = llvm::cast<llvm::StructType>(llt);
// Not sure if we can count on this, may have to take it out
unsigned numElements = llst->getNumElements();
assert(vals.size() == numElements);
// Constant values?
bool isConstant = valuesAreConstant(vals);
std::vector<unsigned long> indexes;
for (unsigned long ii = 0; ii < vals.size(); ++ii)
indexes.push_back(ii);
if (isConstant)
return makeConstCompositeExpr(btype, llst, numElements,
indexes, vals, location);
else
return makeDelayedCompositeExpr(btype, llst, numElements,
indexes, vals, location);
}
Bexpression *
Llvm_backend::makeDelayedCompositeExpr(Btype *btype,
llvm::CompositeType *llct,
unsigned numElements,
const std::vector<unsigned long> &indexes,
const std::vector<Bexpression *> &vals,
Location location) {
unsigned long nvals = vals.size();
std::set<unsigned long> touched;
std::vector<Bexpression *> init_vals(numElements);
for (unsigned ii = 0; ii < indexes.size(); ++ii) {
auto idx = indexes[ii];
if (numElements != nvals)
touched.insert(idx);
init_vals[idx] = vals[ii];
}
if (numElements != nvals) {
for (unsigned long ii = 0; ii < numElements; ++ii) {
Btype *bElemTyp = elementTypeByIndex(btype, ii);
if (touched.find(ii) == touched.end())
init_vals[ii] = zero_expression(bElemTyp);
}
}
// Here the NULL value signals that we want to delay full instantiation
// of this constant expression until we can identify the storage for it.
llvm::Value *nilval = nullptr;
Binstructions instructions;
Bexpression *ccon = nbuilder_.mkComposite(btype, nilval, init_vals,
instructions, location);
return ccon;
}
Bexpression *
Llvm_backend::makeConstCompositeExpr(Btype *btype,
llvm::CompositeType *llct,
unsigned numElements,
const std::vector<unsigned long> &indexes,
const std::vector<Bexpression *> &vals,
Location location) {
unsigned long nvals = vals.size();
std::set<unsigned long> touched;
llvm::SmallVector<llvm::Constant *, 64> llvals(numElements);
for (unsigned ii = 0; ii < indexes.size(); ++ii) {
auto idx = indexes[ii];
if (numElements != nvals)
touched.insert(idx);
Bexpression *bex = vals[ii];
llvm::Constant *con = llvm::cast<llvm::Constant>(bex->value());
llvm::Type *elt = llct->getTypeAtIndex(ii);
if (elt != con->getType())
con = llvm::ConstantExpr::getBitCast(con, elt);
llvals[idx] = con;
}
if (numElements != nvals) {
for (unsigned long ii = 0; ii < numElements; ++ii) {
if (touched.find(ii) == touched.end()) {
llvm::Type *elt = llct->getTypeAtIndex(ii);
llvals[ii] = llvm::Constant::getNullValue(elt);
}
}
}
llvm::Value *scon;
if (llct->isStructTy()) {
llvm::StructType *llst = llvm::cast<llvm::StructType>(llct);
scon = llvm::ConstantStruct::get(llst, llvals);
} else {
llvm::ArrayType *llat = llvm::cast<llvm::ArrayType>(llct);
scon = llvm::ConstantArray::get(llat, llvals);
}
Binstructions instructions;
Bexpression *bcon = nbuilder_.mkComposite(btype, scon, vals,
instructions, location);
return makeGlobalExpression(bcon, scon, btype, location);
}
Bexpression *Llvm_backend::array_constructor_expression(
Btype *array_btype, const std::vector<unsigned long> &indexes,
const std::vector<Bexpression *> &vals, Location location) {
if (array_btype == errorType() || exprVectorHasError(vals))
return errorExpression();
llvm::Type *llt = array_btype->type();
assert(llt->isArrayTy());
llvm::ArrayType *llat = llvm::cast<llvm::ArrayType>(llt);
unsigned numElements = llat->getNumElements();
// frontend should be enforcing this
assert(indexes.size() == vals.size());
// Constant values?
if (valuesAreConstant(vals))
return makeConstCompositeExpr(array_btype, llat, numElements,
indexes, vals, location);
else
return makeDelayedCompositeExpr(array_btype, llat, numElements,
indexes, vals, location);
}
// Return an expression for the address of BASE[INDEX].
Bexpression *Llvm_backend::pointer_offset_expression(Bexpression *base,
Bexpression *index,
Location location) {
if (base == errorExpression() || index == errorExpression())
return errorExpression();
index = resolveVarContext(index);
// Construct an appropriate GEP
llvm::PointerType *llpt =
llvm::cast<llvm::PointerType>(base->btype()->type());
llvm::Value *gep =
makePointerOffsetGEP(llpt, index->value(), base->value());
// Wrap in a Bexpression
Bexpression *rval = nbuilder_.mkArrayIndex(base->btype(), gep, base,
index, location);
if (base->varExprPending())
rval->setVarExprPending(base->varContext());
std::string tag(base->tag());
tag += ".ptroff";
rval->setTag(tag);
// We're done
return rval;
}
// Return an expression representing ARRAY[INDEX]
Bexpression *Llvm_backend::array_index_expression(Bexpression *barray,
Bexpression *index,
Location location) {
if (barray == errorExpression() || index == errorExpression())
return errorExpression();
if (barray->compositeInitPending())
barray = resolveCompositeInit(barray, nullptr);
index = resolveVarContext(index);
// Construct an appropriate GEP
llvm::ArrayType *llat =
llvm::cast<llvm::ArrayType>(barray->btype()->type());
llvm::Value *aval = barray->value();
llvm::Value *ival = index->value();
llvm::Value *eval = nullptr;
bool pending = false;
if (barray->isConstant()) {
if (index->isConstant())
eval = llvm::cast<llvm::Constant>(aval)->getAggregateElement(llvm::cast<llvm::Constant>(ival));
else {
// Constant array with non-constant index. Put the array
// into a temp var and load from there.
llvm::Constant *cval = llvm::cast<llvm::Constant>(aval);
Bvariable *cv = genVarForConstant(cval, barray->btype());
aval = cv->value();
pending = true;
}
}
if (!eval)
eval = makeArrayIndexGEP(llat, ival, aval);
Btype *bet = elementTypeByIndex(barray->btype(), 0);
// Wrap in a Bexpression
Bexpression *rval = nbuilder_.mkArrayIndex(bet, eval, barray, index, location);
if (pending)
rval->setVarExprPending(false, 0);
if (barray->varExprPending())
rval->setVarExprPending(barray->varContext());
std::string tag(barray->tag());
tag += ".index";
rval->setTag(tag);
// We're done
return rval;
}
struct GenCallState {
CABIOracle oracle;
Binstructions instructions;
BinstructionsLIRBuilder builder;
std::vector<Bexpression *> resolvedArgs;
llvm::SmallVector<llvm::Value *, 16> llargs;
llvm::Value *chainVal;
llvm::Value *sretTemp;
BFunctionType *calleeFcnType;
Bfunction *callerFcn;
GenCallState(llvm::LLVMContext &context,
Bfunction *callerFunc,
BFunctionType *calleeFcnTyp,
TypeManager *tm)
: oracle(calleeFcnTyp, tm),
instructions(),
builder(context, &instructions),
chainVal(nullptr),
sretTemp(nullptr),
calleeFcnType(calleeFcnTyp),
callerFcn(callerFunc) { }
};
static bool needSretTemp(const CABIParamInfo &returnInfo,
BFunctionType *calleeFcnTyp)
{
if (returnInfo.disp() == ParmIgnore)
return false;
if (returnInfo.disp() == ParmIndirect)
return true;
if (returnInfo.abiType()->isAggregateType())
return true;
if (calleeFcnTyp->resultType()->type()->isAggregateType())
return true;
return false;
}
void Llvm_backend::genCallProlog(GenCallState &state)
{
const CABIParamInfo &returnInfo = state.oracle.returnInfo();
if (needSretTemp(returnInfo, state.calleeFcnType)) {
assert(state.sretTemp == nullptr);
std::string tname(namegen("sret.actual"));
Btype *resTyp = state.calleeFcnType->resultType();
assert(state.callerFcn);
state.sretTemp = state.callerFcn->createTemporary(resTyp, tname);
if (returnInfo.disp() == ParmIndirect)
state.llargs.push_back(state.sretTemp);
}
// Chain param if needed
const CABIParamInfo &chainInfo = state.oracle.chainInfo();
if (chainInfo.disp() != ParmIgnore) {
assert(chainInfo.disp() == ParmDirect);
llvm::Value *cval = state.chainVal;
if (cval == nullptr)
cval = llvm::UndefValue::get(llvmPtrType());
state.llargs.push_back(cval);
}
}
void
Llvm_backend::genCallMarshallArgs(const std::vector<Bexpression *> &fn_args,
GenCallState &state)
{
const std::vector<Btype *> &paramTypes = state.calleeFcnType->paramTypes();
for (unsigned idx = 0; idx < fn_args.size(); ++idx) {
const CABIParamInfo &paramInfo = state.oracle.paramInfo(idx);
if (paramInfo.attr() == AttrNest)
continue;
// For arguments not passed by value, no call to resolveVarContext
// (we want var address, not var value).
if (paramInfo.disp() == ParmIndirect) {
Bexpression *fnarg = fn_args[idx];
if (fnarg->compositeInitPending())
fnarg = resolveCompositeInit(fnarg, nullptr);
state.resolvedArgs.push_back(fnarg);
llvm::Value *val = fnarg->value();
assert(val);
// spill a constant arg to memory if needed
if (fnarg->isConstant()) {
llvm::Constant *cval = llvm::cast<llvm::Constant>(val);
Bvariable *cv = genVarForConstant(cval, fn_args[idx]->btype());
val = cv->value();
}
assert(val->getType()->isPointerTy());
state.llargs.push_back(val);
continue;
}
// Resolve argument
Varexpr_context ctx = varContextDisp(fn_args[idx]);
if (paramInfo.abiTypes().size() == 2)
ctx = VE_lvalue;
Bexpression *resarg = resolve(fn_args[idx], ctx);
state.resolvedArgs.push_back(resarg);
if (paramInfo.disp() == ParmIgnore)
continue;
// At this point we're passing an argument directly,
// as opposed to in memory.
assert(paramInfo.disp() == ParmDirect);
llvm::Value *val = resarg->value();
BinstructionsLIRBuilder &builder = state.builder;
if (paramInfo.abiTypes().size() == 1) {
if (ctx == VE_lvalue) {
// Passing single-eightbyte struct or array directly.
std::string castname(namegen("cast"));
llvm::Type *ptv = makeLLVMPointerType(paramInfo.abiType());
llvm::Value *bitcast = builder.CreateBitCast(val, ptv, castname);
std::string ltag(namegen("ld"));
llvm::Value *ld = builder.CreateLoad(bitcast, ltag);
state.llargs.push_back(ld);
continue;
}
// Passing a single 8-byte-or-less argument.
// Apply any necessary pointer type conversions.
Btype *paramTyp = paramTypes[idx];
if (val->getType()->isPointerTy() && ctx == VE_rvalue)
val = convertForAssignment(resarg, paramTyp->type());
// Apply any necessary sign-extensions or zero-extensions.
if (paramInfo.abiType()->isIntegerTy()) {
if (paramInfo.attr() == AttrZext)
val = builder.CreateZExt(val, paramInfo.abiType(), namegen("zext"));
else if (paramInfo.attr() == AttrSext)
val = builder.CreateZExt(val, paramInfo.abiType(), namegen("sext"));
}
state.llargs.push_back(val);
continue;
}
// This now corresponds to the case of passing the contents of
// a small structure via two pieces / pararms.
assert(paramInfo.abiTypes().size() == 2);
assert(paramInfo.attr() == AttrNone);
assert(ctx == VE_lvalue);
// Create a struct type of the appropriate shape
llvm::Type *llst = paramInfo.computeABIStructType(typeManager());
llvm::Type *ptst = makeLLVMPointerType(llst);
// If the value we're passing is a composite constant, we have to
// spill it to memory here in order for the casts below to work.
if (llvm::isa<llvm::Constant>(val) && val->getType()->isAggregateType()) {
llvm::Constant *cval = llvm::cast<llvm::Constant>(val);
Bvariable *cv = genVarForConstant(cval, resarg->btype());
val = cv->value();
}
// Cast the value to the struct type
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder.CreateBitCast(val, ptst, tag);
// Load up each field
std::string ftag0(namegen("field0"));
llvm::Value *field0gep =
builder.CreateConstInBoundsGEP2_32(llst, bitcast, 0, 0, ftag0);
std::string ltag0(namegen("ld"));
llvm::Value *ld0 = builder.CreateLoad(field0gep, ltag0);
state.llargs.push_back(ld0);
std::string ftag1(namegen("field1"));
llvm::Value *field1gep =
builder.CreateConstInBoundsGEP2_32(llst, bitcast, 0, 1, ftag1);
std::string ltag1(namegen("ld"));
llvm::Value *ld1 = builder.CreateLoad(field1gep, ltag1);
state.llargs.push_back(ld1);
}
}
void Llvm_backend::genCallAttributes(GenCallState &state, llvm::CallInst *call)
{
// Sret attribute if needed
const CABIParamInfo &returnInfo = state.oracle.returnInfo();
if (returnInfo.disp() == ParmIndirect)
call->addAttribute(1, llvm::Attribute::StructRet);
// Nest attribute if needed
const CABIParamInfo &chainInfo = state.oracle.chainInfo();
if (chainInfo.disp() != ParmIgnore)
call->addAttribute(chainInfo.sigOffset()+1, llvm::Attribute::Nest);
// Remainder of param attributes
const std::vector<Btype *> &paramTypes = state.calleeFcnType->paramTypes();
for (unsigned idx = 0; idx < paramTypes.size(); ++idx) {
const CABIParamInfo &paramInfo = state.oracle.paramInfo(idx);
if (paramInfo.disp() == ParmIgnore)
continue;
assert(paramInfo.attr() != AttrNest);
assert(paramInfo.attr() != AttrStructReturn);
unsigned off = paramInfo.sigOffset() + 1;
if (paramInfo.attr() == AttrByVal)
call->addAttribute(off, llvm::Attribute::ByVal);
else if (paramInfo.attr() == AttrZext)
call->addAttribute(off, llvm::Attribute::ZExt);
else if (paramInfo.attr() == AttrSext)
call->addAttribute(off, llvm::Attribute::SExt);
}
}
void Llvm_backend::genCallEpilog(GenCallState &state,
llvm::Instruction *callInst,
Bexpression *callExpr)
{
const CABIParamInfo &returnInfo = state.oracle.returnInfo();
if (needSretTemp(returnInfo, state.calleeFcnType)) {
assert(state.sretTemp);
assert(callExpr->value() == state.sretTemp);
callExpr->setVarExprPending(VE_rvalue, 0);
if (returnInfo.disp() == ParmDirect) {
// The call is returning something by value that doesn't match
// the expected abstract result type of the function. Cast the
// sret storage location to a pointer to the abi type and store
// the ABI return value into it.
BinstructionsLIRBuilder builder(context_, callExpr);
llvm::Type *rt = (returnInfo.abiTypes().size() == 1 ?
returnInfo.abiType() :
returnInfo.computeABIStructType(typeManager()));
llvm::Type *ptrt = makeLLVMPointerType(rt);
std::string castname(namegen("cast"));
llvm::Value *bitcast = builder.CreateBitCast(state.sretTemp,
ptrt, castname);
std::string stname(namegen("st"));
builder.CreateStore(callInst, bitcast);
}
}
}
// Create an expression for a call to FN_EXPR with FN_ARGS.
Bexpression *
Llvm_backend::call_expression(Bfunction *caller,
Bexpression *fn_expr,
const std::vector<Bexpression *> &fn_args,
Bexpression *chain_expr,
Location location) {
if (fn_expr == errorExpression() || exprVectorHasError(fn_args) ||
chain_expr == errorExpression())
return errorExpression();
// Resolve fcn. Expect pointer-to-function type here.
fn_expr = resolveVarContext(fn_expr);
assert(fn_expr->btype()->type()->isPointerTy());
Btype *rbtype = functionReturnType(fn_expr->btype());
// Collect function type and param types
BPointerType *bpft = fn_expr->btype()->castToBPointerType();
BFunctionType *calleeFcnTyp = bpft->toType()->castToBFunctionType();
assert(calleeFcnTyp);
GenCallState state(context_, caller, calleeFcnTyp, typeManager());
state.resolvedArgs.push_back(fn_expr);
// Static chain expression if applicable
if (chain_expr) {
chain_expr = resolveVarContext(chain_expr);
assert(chain_expr->btype()->type()->isPointerTy());
Btype *bpt = makeAuxType(llvmPtrType());
chain_expr = convert_expression(bpt, chain_expr, location);
state.resolvedArgs.push_back(chain_expr);
state.chainVal = chain_expr->value();
}
// Set up for call (including creation of return tmp if needed)
genCallProlog(state);
// Unpack / resolve / marshall arguments
genCallMarshallArgs(fn_args, state);
// Create the actual call instruction
llvm::FunctionType *llft =
llvm::cast<llvm::FunctionType>(calleeFcnTyp->type());
bool isvoid = llft->getReturnType()->isVoidTy();
std::string callname(isvoid ? "" : namegen("call"));
llvm::CallInst *call =
state.builder.CreateCall(llft, fn_expr->value(),
state.llargs, callname);
genCallAttributes(state, call);
llvm::Value *callValue = (state.sretTemp ? state.sretTemp : call);
Bexpression *rval =
nbuilder_.mkCall(rbtype, callValue, state.resolvedArgs,
state.instructions, location);
state.instructions.clear();
genCallEpilog(state, call, rval);
return rval;
}
// Return an expression that allocates SIZE bytes on the stack.
Bexpression *Llvm_backend::stack_allocation_expression(int64_t size,
Location location) {
assert(false && "Llvm_backend::stack_allocation_expression not yet impl");
return nullptr;
}
Bstatement *Llvm_backend::error_statement()
{
errorCount_++;
return errorStatement();
}
// An expression as a statement.
Bstatement *Llvm_backend::expression_statement(Bfunction *bfunction,
Bexpression *expr)
{
if (expr == errorExpression() || bfunction == errorFunction_.get())
return errorStatement();
Bstatement *es =
nbuilder_.mkExprStmt(bfunction, resolve(expr), expr->location());
return es;
}
// Variable initialization.
Bstatement *Llvm_backend::init_statement(Bfunction *bfunction,
Bvariable *var,
Bexpression *init)
{
if (var == errorVariable_.get() || init == errorExpression() ||
bfunction == errorFunction_.get())
return errorStatement();
return makeInitStatement(bfunction, var, init);
}
Bstatement *Llvm_backend::makeInitStatement(Bfunction *bfunction,
Bvariable *var,
Bexpression *init)
{
if (init) {
if (init->compositeInitPending()) {
init = resolveCompositeInit(init, var->value());
Bstatement *es = nbuilder_.mkExprStmt(bfunction, init,
init->location());
var->setInitializer(es->getExprStmtExpr()->value());
return es;
}
} else {
init = zero_expression(var->btype());
}
Bexpression *varexp = nbuilder_.mkVar(var, var->location());
Bstatement *st = makeAssignment(bfunction, var->value(),
varexp, init, Location());
llvm::Value *ival = st->getExprStmtExpr()->value();
if (! llvm::isa<llvm::UndefValue>(ival))
var->setInitializer(ival);
return st;
}
llvm::Value *
Llvm_backend::convertForAssignment(Bexpression *src,
llvm::Type *dstToType)
{
if (src->value()->getType() == dstToType)
return src->value();
llvm::Function *dummyFcn = errorFunction_->function();
BlockLIRBuilder builder(dummyFcn, this);
llvm::Value *val = convertForAssignment(src->btype(), src->value(),
dstToType, &builder);
src->appendInstructions(builder.instructions());
return val;
}
llvm::Value *
Llvm_backend::convertForAssignment(Btype *srcBType,
llvm::Value *srcVal,
llvm::Type *dstToType,
BlockLIRBuilder *builder)
{
llvm::Type *srcType = srcBType->type();
if (dstToType == srcType)
return srcVal;
// Case 1: handle discrepancies between representations of function
// descriptors. All front end function descriptor types are structs
// with a single field, however this field can sometimes be a pointer
// to function, and sometimes it can be of uintptr type.
bool srcPtrToFD = isPtrToFuncDescriptorType(srcType);
bool dstPtrToFD = isPtrToFuncDescriptorType(dstToType);
if (srcPtrToFD && dstPtrToFD) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
// Case 2: handle circular function pointer types.
bool dstCircPtr = isCircularPointerType(dstToType);
if (srcPtrToFD && dstCircPtr) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
// Case 3: handle raw function pointer assignment (frontend will
// sometimes take a function pointer and assign it to "void *" without
// an explicit conversion).
bool dstPtrToVoid = isPtrToVoidType(dstToType);
bool srcFuncPtr = isPtrToFuncType(srcType);
if (dstPtrToVoid && srcFuncPtr) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
// Case 4: in some cases when calling a function (for example, __gogo)
// the front end will pass a raw function vale in place of a function
// descriptor. Allow this case.
if (dstPtrToFD && srcFuncPtr) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
// Case 5: handle polymorphic nil pointer expressions-- these are
// generated without a type initially, so we need to convert them
// to the appropriate type if they appear in an assignment context.
if (srcVal == nil_pointer_expression()->value()) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
// Case 6: the code that creates interface values stores pointers of
// various flavors into i8*. Ideally it would be better to insert
// forced type conversions in the FE, but for now we allow this case.
bool srcPtrToIface = isPtrToIfaceStructType(srcType);
if (dstPtrToVoid && srcPtrToIface) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
// Case 7: when creating slice values it's common for the frontend
// to mix pointers and arrays, e.g. assign "[3 x i64]*" to "i64**".
// Allow this sort of conversion.
llvm::Type *elt =
(dstToType->isPointerTy() ?
llvm::cast<llvm::PointerType>(dstToType)->getElementType() : nullptr);
if (elt && isPtrToArrayOf(srcType, elt)) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
// Case 8: also when creating slice values it's common for the
// frontend to assign pointer-to-X to unsafe.Pointer (and vice versa)
// without an explicit cast. Allow this for now.
if ((dstToType == llvmPtrType() && llvm::isa<llvm::PointerType>(srcType)) ||
(srcType == llvmPtrType() && llvm::isa<llvm::PointerType>(dstToType))) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
// Case 9: related to case 1 above, interface value expressions can
// contain C function pointers stored as "void *" instead of
// concrete pointer-to-function values. For example, consider a
// value V1 of the form
//
// { { T1*, void* }, O* }
//
// where T1 is a type descriptor and O is an object; this value can
// sometimes be assigned to a location of type
//
// { { T1*, F* }, O* }
//
// where F is a concrete C pointer-to-function (as opposed to "void*").
// Allow conversions of this sort for now.
std::set<llvm::Type *> visited;
if (fcnPointerCompatible(dstToType, srcType, visited)) {
std::string tag(namegen("cast"));
llvm::Value *bitcast = builder->CreateBitCast(srcVal, dstToType, tag);
return bitcast;
}
return srcVal;
}
Bstatement *Llvm_backend::makeAssignment(Bfunction *function,
llvm::Value *lval, Bexpression *lhs,
Bexpression *rhs, Location location)
{
assert(lval->getType()->isPointerTy());
// This cases should have been handled in the caller
assert(!rhs->compositeInitPending());
// Invoke helper to create store or memcpy
Bexpression *stexp = genStore(function, rhs, lhs, location);
// Return wrapped in statement
return nbuilder_.mkExprStmt(function, stexp, location);
}
// Assignment.
Bstatement *Llvm_backend::assignment_statement(Bfunction *bfunction,
Bexpression *lhs,
Bexpression *rhs,
Location location) {
if (lhs == errorExpression() || rhs == errorExpression() ||
bfunction == errorFunction_.get())
return errorStatement();
Bexpression *lhs2 = resolveVarContext(lhs, VE_lvalue);
Bexpression *rhs2 = rhs;
if (rhs->compositeInitPending()) {
rhs2 = resolveCompositeInit(rhs, lhs2->value());
Bexpression *stexp =
nbuilder_.mkBinaryOp(OPERATOR_EQ, voidType(), lhs2->value(),
lhs2, rhs2, location);
Bstatement *es = nbuilder_.mkExprStmt(bfunction, stexp, location);
return es;
}
Bstatement *st = makeAssignment(bfunction, lhs->value(),
lhs2, rhs2, location);
return st;
}
Bstatement*
Llvm_backend::return_statement(Bfunction *bfunction,
const std::vector<Bexpression *> &vals,
Location location)
{
if (bfunction == errorFunction_.get() || exprVectorHasError(vals))
return errorStatement();
// Resolve arguments
std::vector<Bexpression *> resolvedVals;
for (auto &val : vals)
resolvedVals.push_back(resolve(val, varContextDisp(val)));
// Collect up the return value
Bexpression *toret = nullptr;
if (vals.size() == 0) {
// The return Bexpression node has a single child, so in the case
// of the void function, create a dummy return value (easier than
// making return a variadic node).
toret = nbuilder_.mkConst(voidType(),
llvm::UndefValue::get(llvmVoidType()));
} else if (vals.size() == 1) {
toret = resolvedVals[0];
} else {
Btype *rtyp = bfunction->fcnType()->resultType();
Bexpression *structVal =
constructor_expression(rtyp, resolvedVals, location);
if (structVal->compositeInitPending()) {
structVal = resolveCompositeInit(structVal, nullptr);
} else if (structVal->isConstant()) {
llvm::Constant *cval = llvm::cast<llvm::Constant>(structVal->value());
Bvariable *cv = genVarForConstant(cval, structVal->btype());
structVal = var_expression(cv, VE_rvalue, location);
structVal = address_expression(structVal, location);
}
toret = structVal;
}
Binstructions retInsns;
llvm::Value *rval = bfunction->genReturnSequence(toret, &retInsns, this);
llvm::ReturnInst *ri = llvm::ReturnInst::Create(context_, rval);
toret->appendInstructions(retInsns.instructions());
toret->appendInstruction(ri);
Bstatement *rst =
nbuilder_.mkReturn(bfunction, toret, location);
return rst;
}
// Create a statement that attempts to execute BSTAT and calls EXCEPT_STMT if an
// error occurs. EXCEPT_STMT may be NULL. FINALLY_STMT may be NULL and if not
// NULL, it will always be executed. This is used for handling defers in Go
// functions. In C++, the resulting code is of this form:
// try { BSTAT; } catch { EXCEPT_STMT; } finally { FINALLY_STMT; }
Bstatement *Llvm_backend::exception_handler_statement(Bstatement *bstat,
Bstatement *except_stmt,
Bstatement *finally_stmt,
Location location)
{
if (bstat == errorStatement() ||
except_stmt == errorStatement() ||
finally_stmt == errorStatement())
return errorStatement();
Bfunction *func = bstat->function();
assert(func == except_stmt->function());
assert(!finally_stmt || func == finally_stmt->function());
Bstatement *excepst = nbuilder_.mkExcepStmt(func, bstat,
except_stmt,
finally_stmt, location);
return excepst;
}
// If statement.
Bstatement *Llvm_backend::if_statement(Bfunction *bfunction,
Bexpression *condition,
Bblock *then_block, Bblock *else_block,
Location location) {
if (condition == errorExpression())
return errorStatement();
condition = resolve(condition);
assert(then_block);
Btype *bt = makeAuxType(llvmBoolType());
Bexpression *conv = convert_expression(bt, condition, location);
Bstatement *ifst = nbuilder_.mkIfStmt(bfunction, conv, then_block,
else_block, location);
return ifst;
}
// Switch.
Bstatement *Llvm_backend::switch_statement(Bfunction *bfunction,
Bexpression *value,
const std::vector<std::vector<Bexpression *>> &cases,
const std::vector<Bstatement *> &statements, Location switch_location)
{
// Error handling
if (value == errorExpression())
return errorStatement();
for (auto casev : cases)
if (exprVectorHasError(casev))
return errorStatement();
if (stmtVectorHasError(statements))
return errorStatement();
// Resolve value
value = resolve(value);
// Case expressions are expected to be constants for this flavor of switch
for (auto &bexpvec : cases)
for (auto &exp : bexpvec)
if (! llvm::cast<llvm::Constant>(exp->value()))
go_assert(false && "bad case value expression");
// Store results stmt
Bstatement *swst =
nbuilder_.mkSwitchStmt(bfunction, value, cases, statements,
switch_location);
return swst;
}
// Pair of statements.
Bstatement *Llvm_backend::compound_statement(Bstatement *s1, Bstatement *s2) {
if (s1 == errorStatement() || s2 == errorStatement())
return errorStatement();
assert(!s1->function() || !s2->function() ||
s1->function() == s2->function());
std::vector<Bstatement *> stvec;
stvec.push_back(s1);
stvec.push_back(s2);
return statement_list(stvec);
}
// List of statements.
Bstatement *
Llvm_backend::statement_list(const std::vector<Bstatement *> &statements) {
Bfunction *func = nullptr;
for (auto &st : statements) {
if (st == errorStatement())
return errorStatement();
if (st->function()) {
if (func)
assert(st->function() == func);
else
func = st->function();
}
}
std::vector<Bvariable *> novars;
Bblock *block = nbuilder_.mkBlock(func, novars, Location());
for (auto &st : statements)
nbuilder_.addStatementToBlock(block, st);
return block;
}
Bblock *Llvm_backend::block(Bfunction *function, Bblock *enclosing,
const std::vector<Bvariable *> &vars,
Location start_location, Location) {
assert(function);
// FIXME: record debug location
// Create new Bblock
Bblock *bb = nbuilder_.mkBlock(function, vars, start_location);
function->addBlock(bb);
// FIXME:
// Mark start and end of lifetime for each variable
// for (auto var : vars) {
// Not yet implemented
// }
return bb;
}
// Add statements to a block.
void Llvm_backend::block_add_statements(Bblock *bblock,
const std::vector<Bstatement *> &statements) {
for (auto st : statements)
if (st == errorStatement())
return;
assert(bblock);
for (auto st : statements)
nbuilder_.addStatementToBlock(bblock, st);
}
// Return a block as a statement.
Bstatement *Llvm_backend::block_statement(Bblock *bblock)
{
return bblock; // class Bblock inherits from Bstatement
}
// Helper routine for creating module-scope variables (static, global, etc).
Bvariable *
Llvm_backend::makeModuleVar(Btype *btype,
const std::string &name,
const std::string &asm_name,
Location location,
ModVarConstant isConstant,
ModVarSec inUniqueSection,
ModVarComdat inComdat,
ModVarVis isHiddenVisibility,
ModVarExtInit isExtInit,
llvm::GlobalValue::LinkageTypes linkage,
llvm::Constant *initializer,
unsigned alignment)
{
if (btype == errorType())
return errorVariable_.get();
#if 0
// FIXME: add code to insure non-zero size
assert(datalayout().getTypeSizeInBits(btype->type()) != 0);
#endif
// FIXME: at the moment the driver is enabling separate sections
// for all variables, since there doesn't seem to be an easily
// accessible hook for requesting a separate section for a single
// variable.
assert(inUniqueSection == MV_DefaultSection);
// FIXME: add DIGlobalVariable to debug info for this variable
llvm::Constant *init =
(isExtInit == MV_ExternallyInitialized ? nullptr :
llvm::Constant::getNullValue(btype->type()));
std::string gname(asm_name.empty() ? name : asm_name);
llvm::GlobalVariable *glob = new llvm::GlobalVariable(
module(), btype->type(), isConstant == MV_Constant,
linkage, init, gname);
if (isHiddenVisibility == MV_HiddenVisibility)
glob->setVisibility(llvm::GlobalValue::HiddenVisibility);
if (alignment)
glob->setAlignment(alignment);
if (initializer)
glob->setInitializer(initializer);
if (inComdat == MV_InComdat) {
assert(! gname.empty());
glob->setComdat(module().getOrInsertComdat(gname));
}
if (isExtInit == MV_ExternallyInitialized) {
assert(!init);
glob->setExternallyInitialized(true);
}
bool addressTaken = true; // for now
Bvariable *bv =
new Bvariable(btype, location, gname, GlobalVar, addressTaken, glob);
assert(valueVarMap_.find(bv->value()) == valueVarMap_.end());
valueVarMap_[bv->value()] = bv;
return bv;
}
// Make a global variable.
Bvariable *Llvm_backend::global_variable(const std::string &var_name,
const std::string &asm_name,
Btype *btype,
bool is_external,
bool is_hidden,
bool in_unique_section,
Location location)
{
llvm::GlobalValue::LinkageTypes linkage = llvm::GlobalValue::ExternalLinkage;
ModVarSec inUniqSec =
(in_unique_section ? MV_UniqueSection : MV_DefaultSection);
ModVarVis varVis =
(is_hidden ? MV_HiddenVisibility : MV_DefaultVisibility);
ModVarExtInit extInit =
(is_external ? MV_ExternallyInitialized : MV_NotExternallyInitialized);
Bvariable *gvar =
makeModuleVar(btype, var_name, asm_name, location,
MV_NonConstant, inUniqSec, MV_NotInComdat,
varVis, extInit, linkage, nullptr);
return gvar;
}
// Set the initial value of a global variable.
void Llvm_backend::global_variable_set_init(Bvariable *var, Bexpression *expr)
{
if (var == errorVariable_.get() || expr == errorExpression())
return;
assert(llvm::isa<llvm::GlobalVariable>(var->value()));
llvm::GlobalVariable *gvar = llvm::cast<llvm::GlobalVariable>(var->value());
if (expr->compositeInitPending())
expr = resolveCompositeInit(expr, gvar);
assert(llvm::isa<llvm::Constant>(expr->value()));
llvm::Constant *econ = llvm::cast<llvm::Constant>(expr->value());
gvar->setInitializer(econ);
}
Bvariable *Llvm_backend::error_variable()
{
errorCount_++;
return errorVariable_.get();
}
// Make a local variable.
Bvariable *Llvm_backend::local_variable(Bfunction *function,
const std::string &name,
Btype *btype,
bool is_address_taken,
Location location)
{
assert(function);
if (btype == errorType() || function == errorFunction_.get())
return errorVariable_.get();
return function->localVariable(name, btype, is_address_taken, location);
}
// Make a function parameter variable.
Bvariable *Llvm_backend::parameter_variable(Bfunction *function,
const std::string &name,
Btype *btype, bool is_address_taken,
Location location)
{
assert(function);
if (btype == errorType() || function == errorFunction_.get())
return errorVariable_.get();
return function->parameterVariable(name, btype,
is_address_taken, location);
}
// Make a static chain variable.
Bvariable *Llvm_backend::static_chain_variable(Bfunction *function,
const std::string &name,
Btype *btype,
Location location)
{
if (function == errorFunction_.get() || btype == errorType())
return errorVariable_.get();
return function->staticChainVariable(name, btype, location);
}
// Make a temporary variable.
Bvariable *Llvm_backend::temporary_variable(Bfunction *function,
Bblock *bblock,
Btype *btype,
Bexpression *binit,
bool is_address_taken,
Location location,
Bstatement **pstatement)
{
if (binit == errorExpression())
return errorVariable_.get();
std::string tname(namegen("tmpv"));
Bvariable *tvar = local_variable(function, tname, btype,
is_address_taken, location);
if (tvar == errorVariable_.get())
return tvar;
tvar->markAsTemporary();
Bstatement *is = init_statement(function, tvar, binit);
*pstatement = is;
return tvar;
}
// Create an implicit variable that is compiler-defined. This is used when
// generating GC root variables and storing the values of a slice initializer.
Bvariable *Llvm_backend::implicit_variable(const std::string &name,
const std::string &asm_name,
Btype *btype,
bool is_hidden,
bool is_constant,
bool is_common,
int64_t ialignment)
{
if (btype == errorType())
return errorVariable_.get();
// Vett alignment
assert(ialignment >= 0);
assert(ialignment < 1<<30);
unsigned alignment = static_cast<unsigned>(ialignment);
// Common + hidden makes no sense
assert(!(is_hidden && is_common));
llvm::GlobalValue::LinkageTypes linkage =
(is_hidden ? llvm::GlobalValue::InternalLinkage
: llvm::GlobalValue::ExternalLinkage);
ModVarComdat inComdat = (is_common ? MV_InComdat : MV_NotInComdat);
ModVarSec inUniqSec = MV_DefaultSection;
ModVarVis varVis = MV_DefaultVisibility;
ModVarConstant isConst = (is_constant ? MV_Constant : MV_NonConstant);
ModVarExtInit extInit = MV_NotExternallyInitialized;
Bvariable *gvar =
makeModuleVar(btype, name, asm_name, Location(),
isConst, inUniqSec, inComdat,
varVis, extInit, linkage, nullptr, alignment);
return gvar;
}
// Set the initalizer for a variable created by implicit_variable.
// This is where we finish compiling the variable.
void Llvm_backend::implicit_variable_set_init(Bvariable *var,
const std::string &,
Btype *type,
bool, bool, bool is_common,
Bexpression *init)
{
if (init != nullptr && init == errorExpression())
return;
if (var == errorVariable_.get())
return;
if (!init)
init = zero_expression(type);
global_variable_set_init(var, init);
}
// Return a reference to an implicit variable defined in another package.
Bvariable *Llvm_backend::implicit_variable_reference(const std::string &name,
const std::string &asmname,
Btype *btype)
{
assert(false && "Llvm_backend::implicit_variable_reference not yet impl");
return nullptr;
}
// Create a named immutable initialized data structure.
Bvariable *Llvm_backend::immutable_struct(const std::string &name,
const std::string &asm_name,
bool is_hidden,
bool is_common,
Btype *btype,
Location location)
{
if (btype == errorType())
return errorVariable_.get();
// Common + hidden makes no sense
assert(!(is_hidden && is_common));
llvm::GlobalValue::LinkageTypes linkage =
(is_hidden ? llvm::GlobalValue::InternalLinkage
: llvm::GlobalValue::ExternalLinkage);
ModVarSec inUniqueSec = MV_DefaultSection;
ModVarComdat inComdat = (is_common ? MV_InComdat : MV_NotInComdat);
ModVarVis varVis = MV_DefaultVisibility;
ModVarExtInit extInit = MV_NotExternallyInitialized;
Bvariable *gvar =
makeModuleVar(btype, name, asm_name, location,
MV_Constant, inUniqueSec, inComdat,
varVis, extInit, linkage, nullptr);
return gvar;
}
// Set the initializer for a variable created by immutable_struct.
// This is where we finish compiling the variable.
void Llvm_backend::immutable_struct_set_init(Bvariable *var,
const std::string &,
bool is_hidden,
bool is_common,
Btype *,
Location,
Bexpression *initializer)
{
if (var == errorVariable_.get() || initializer == errorExpression())
return;
assert(llvm::isa<llvm::GlobalVariable>(var->value()));
llvm::GlobalVariable *gvar = llvm::cast<llvm::GlobalVariable>(var->value());
assert(llvm::isa<llvm::Constant>(var->value()));
llvm::Constant *econ = llvm::cast<llvm::Constant>(initializer->value());
gvar->setInitializer(econ);
}
// Return a reference to an immutable initialized data structure
// defined in another package.
Bvariable *Llvm_backend::immutable_struct_reference(const std::string &name,
const std::string &asm_name,
Btype *btype,
Location location)
{
if (btype == errorType())
return errorVariable_.get();
// Seen this already?
std::string gname(asm_name.empty() ? name : asm_name);
auto it = immutableStructRefs_.find(gname);
if (it != immutableStructRefs_.end()) {
// type should agree
Bvariable *existing = it->second;
assert(btype->type() == existing->btype()->type());
return existing;
}
// Create new external global
llvm::GlobalValue::LinkageTypes linkage = llvm::GlobalValue::ExternalLinkage;
bool isConstant = true;
llvm::Constant *init = nullptr;
llvm::GlobalVariable *glob = new llvm::GlobalVariable(
module(), btype->type(), isConstant, linkage, init, gname);
Bvariable *bv =
new Bvariable(btype, location, name, GlobalVar, false, glob);
assert(valueVarMap_.find(bv->value()) == valueVarMap_.end());
valueVarMap_[bv->value()] = bv;
immutableStructRefs_[gname] = bv;
return bv;
}
// Make a label.
Blabel *Llvm_backend::label(Bfunction *function,
const std::string &name,
Location location)
{
assert(function);
return function->newLabel(location);
}
// Make a statement which defines a label.
Bstatement *Llvm_backend::label_definition_statement(Blabel *label)
{
Bfunction *function = label->function();
Bstatement *st = nbuilder_.mkLabelDefStmt(function, label, label->location());
function->registerLabelDefStatement(st, label);
return st;
}
// Make a goto statement.
Bstatement *Llvm_backend::goto_statement(Blabel *label, Location location)
{
Bfunction *function = label->function();
return nbuilder_.mkGotoStmt(function, label, location);
}
// Get the address of a label.
Bexpression *Llvm_backend::label_address(Blabel *label, Location location)
{
assert(label);
// Reuse existing placeholder (if address already taken for this label), or
// create new placeholder if needed.
llvm::Value *pval = nullptr;
if (label->placeholder()) {
pval = label->placeholder();
} else {
Bfunction *fcn = label->function();
pval = fcn->createLabelAddressPlaceholder(boolType());
label->setPlaceholder(pval);
}
// Note: the expression we're creating will eventually be replaced
// by an llvm::BlockAddress value, which will have type "i8*", so
// use that type here so as to avoid having to insert conversions.
Btype *ppt = pointerType(boolType());
return nbuilder_.mkLabelAddress(ppt, pval, label, location);
}
Bfunction *Llvm_backend::error_function()
{
errorCount_++;
return errorFunction_.get();
}
// Declare or define a new function.
Bfunction *Llvm_backend::function(Btype *fntype, const std::string &name,
const std::string &asm_name, bool is_visible,
bool is_declaration, bool is_inlinable,
bool disable_split_stack,
bool in_unique_section, Location location)
{
if (fntype == errorType())
return errorFunction_.get();
// If this is a declaration, then look to see if we already have an existing
// function with the same name, and reuse that if need be. Check to make
// sure that the function types agree if we see a hit in the cache.
std::string fns(!asm_name.empty() ? asm_name : name);
llvm::FunctionType *fty = llvm::cast<llvm::FunctionType>(fntype->type());
if (is_declaration) {
auto it = fcnNameMap_.find(fns);
if (it != fcnNameMap_.end()) {
Bfunction *found = it->second;
assert(found->fcnType()->type() == fty);
return found;
}
}
llvm::GlobalValue::LinkageTypes linkage = llvm::GlobalValue::ExternalLinkage;
llvm::Twine fn(fns);
llvm::Function *fcn = llvm::Function::Create(fty, linkage, fn, module_);
fcn->addFnAttr("disable-tail-calls", "true");
// visibility
if (!is_visible)
fcn->setVisibility(llvm::GlobalValue::HiddenVisibility);
// inline/noinline
if (!is_inlinable)
fcn->addFnAttr(llvm::Attribute::NoInline);
BFunctionType *fcnType = fntype->castToBFunctionType();
assert(fcnType);
Bfunction *bfunc = new Bfunction(fcn, fcnType, name, asm_name, location,
typeManager());
// split-stack or nosplit
if (! disable_split_stack)
fcn->addFnAttr("split-stack");
else
bfunc->setSplitStack(Bfunction::NoSplit);
// TODO: unique section support. llvm::GlobalObject has support for
// setting COMDAT groups and section names, but there doesn't seem
// to be an interface available to request a unique section on a
// per-function basis (only a translation-unit-wide default).
assert(!in_unique_section || is_declaration);
if (is_declaration)
fcnNameMap_[fns] = bfunc;
functions_.push_back(bfunc);
return bfunc;
}
// Create a statement that runs all deferred calls for FUNCTION. This should
// be a statement that looks like this in C++:
// finish:
// try { UNDEFER; } catch { CHECK_DEFER; goto finish; }
Bstatement *Llvm_backend::function_defer_statement(Bfunction *function,
Bexpression *undefer,
Bexpression *defer,
Location location)
{
if (function == errorFunction_.get() ||
undefer == errorExpression() ||
defer == errorExpression())
return errorStatement();
Bstatement *defst = nbuilder_.mkDeferStmt(function, undefer, defer,
location);
return defst;
}
// Record PARAM_VARS as the variables to use for the parameters of FUNCTION.
// This will only be called for a function definition.
bool Llvm_backend::function_set_parameters(
Bfunction *function, const std::vector<Bvariable *> &param_vars)
{
// At the moment this is a no-op.
return true;
}
//
// Helper class for assigning instructions to LLVM basic blocks
// and materializing control transfers.
//
// FIXME: convert to use new Bnode walk paradigm.
//
class GenBlocks {
public:
GenBlocks(llvm::LLVMContext &context, Llvm_backend *be,
Bfunction *function, Bnode *topNode, llvm::DIScope *scope,
bool createDebugMetadata, llvm::BasicBlock *entryBlock);
llvm::BasicBlock *walk(Bnode *node, llvm::BasicBlock *curblock);
void finishFunction(llvm::BasicBlock *entry);
Bfunction *function() { return function_; }
llvm::BasicBlock *genIf(Bstatement *ifst,
llvm::BasicBlock *curblock);
llvm::BasicBlock *genSwitch(Bstatement *swst,
llvm::BasicBlock *curblock);
llvm::BasicBlock *genDefer(Bstatement *defst,
llvm::BasicBlock *curblock);
llvm::BasicBlock *genReturn(Bstatement *rst,
llvm::BasicBlock *curblock);
llvm::BasicBlock *genExcep(Bstatement *excepst,
llvm::BasicBlock *curblock);
private:
llvm::BasicBlock *mkLLVMBlock(const std::string &name,
unsigned expl = Llvm_backend::ChooseVer);
llvm::BasicBlock *getBlockForLabel(Blabel *lab);
llvm::BasicBlock *walkExpr(llvm::BasicBlock *curblock, Bexpression *expr);
std::pair<llvm::Instruction*, llvm::BasicBlock *>
rewriteToMayThrowCall(llvm::CallInst *call,
llvm::BasicBlock *curblock);
std::pair<llvm::Instruction*, llvm::BasicBlock *>
postProcessInst(llvm::Instruction *inst,
llvm::BasicBlock *curblock);
llvm::DIBuilder &dibuilder() { return be_->dibuilder(); }
DIBuildHelper &dibuildhelper() { return *dibuildhelper_.get(); }
Llvm_linemap *linemap() { return be_->linemap(); }
private:
llvm::LLVMContext &context_;
Llvm_backend *be_;
Bfunction *function_;
std::unique_ptr<DIBuildHelper> dibuildhelper_;
std::map<LabelId, llvm::BasicBlock *> labelmap_;
std::vector<llvm::BasicBlock*> padBlockStack_;
std::set<llvm::AllocaInst *> temporariesDiscovered_;
llvm::BasicBlock* finallyBlock_;
Bstatement *cachedReturn_;
bool emitOrphanedCode_;
bool createDebugMetaData_;
};
GenBlocks::GenBlocks(llvm::LLVMContext &context,
Llvm_backend *be,
Bfunction *function,
Bnode *topNode,
llvm::DIScope *scope,
bool createDebugMetadata,
llvm::BasicBlock *entryBlock)
: context_(context), be_(be), function_(function),
dibuildhelper_(nullptr), finallyBlock_(nullptr),
cachedReturn_(nullptr), emitOrphanedCode_(false),
createDebugMetaData_(createDebugMetadata)
{
if (createDebugMetaData_) {
dibuildhelper_.reset(new DIBuildHelper(topNode,
be->typeManager(),
be->linemap(),
be->dibuilder(),
be->getDICompUnit(),
entryBlock));
dibuildhelper().beginFunction(scope, function);
}
}
void GenBlocks::finishFunction(llvm::BasicBlock *entry)
{
function_->fixupProlog(entry, temporariesDiscovered_);
if (createDebugMetaData_)
dibuildhelper().endFunction(function_);
}
llvm::BasicBlock *GenBlocks::mkLLVMBlock(const std::string &name,
unsigned expl)
{
std::string tname = be_->namegen(name, expl);
llvm::Function *func = function()->function();
return llvm::BasicBlock::Create(context_, tname, func);
}
llvm::BasicBlock *GenBlocks::getBlockForLabel(Blabel *lab) {
auto it = labelmap_.find(lab->label());
if (it != labelmap_.end())
return it->second;
llvm::BasicBlock *bb = mkLLVMBlock("label", lab->label());
labelmap_[lab->label()] = bb;
return bb;
}
// This helper routine takes a garden variety call instruction and
// rewrites it to an equivalent llvm::InvokeInst that may throw an
// exception (with associated explicit EH control flow). The helper is
// used to fix up calls that appear within the body or catch clauses
// of an EH statement (see Llvm_backend::exception_handler_statement).
// Redoing calls in this way (as opposed to creating the correct
// flavor of call from the get-go) is mildly hacky, but seems to be
// the most practical way to get the sort of call we need, given that
// at the point where Backend::call_expression is originally invoked
// we don't know whether the call will reside in a try block.
std::pair<llvm::Instruction*, llvm::BasicBlock *>
GenBlocks::rewriteToMayThrowCall(llvm::CallInst *call,
llvm::BasicBlock *curblock)
{
llvm::BasicBlock *padbb = padBlockStack_.back();
llvm::Function *func = function()->function();
// Create 'continue' block, where control will flow if
// the call to the function does not result in an exception.
llvm::BasicBlock *contbb =
llvm::BasicBlock::Create(context_, be_->namegen("cont"), func);
// Create a new InvokeInst that is equivalent (in terms of
// target, operands, etc) to the CallInst 'call', but uses a
// possibly-excepting call with landing pad.
llvm::SmallVector<llvm::Value *, 8> args(call->arg_begin(), call->arg_end());
llvm::InvokeInst *invcall =
llvm::InvokeInst::Create(call->getCalledValue(),
contbb, padbb, args,
call->getName());
// Rewrite uses of the original call's return value to be the new call's
// return value.
call->replaceAllUsesWith(invcall);
// New call needs same attributes
invcall->setAttributes(call->getAttributes());
// Old call longer needed
call->deleteValue();
return std::make_pair(invcall, contbb);
}
// Hook to post-process an LLVM instruction immediately before it
// is assigned to a block.
std::pair<llvm::Instruction*, llvm::BasicBlock *>
GenBlocks::postProcessInst(llvm::Instruction *inst,
llvm::BasicBlock *curblock)
{
for (llvm::Instruction::op_iterator oi = inst->op_begin(),
oe = inst->op_end(); oi != oe; ++oi) {
if (llvm::isa<llvm::AllocaInst>(*oi)) {
llvm::AllocaInst *ai = llvm::cast<llvm::AllocaInst>(*oi);
// If this alloca is associated with a temporary variable
// that was manufactured at some point during IR construction,
// then gather it up into a set to be inserted into the prolog
// block.
Bvariable *tvar = be_->nodeBuilder().adoptTemporaryVariable(ai);
if (tvar) {
temporariesDiscovered_.insert(ai);
delete tvar;
}
}
}
if (llvm::isa<llvm::CallInst>(inst) && !padBlockStack_.empty()) {
llvm::CallInst *call = llvm::cast<llvm::CallInst>(inst);
llvm::Function *func = call->getCalledFunction();
if (!func || !func->isIntrinsic())
return rewriteToMayThrowCall(call, curblock);
}
return std::make_pair(inst, curblock);
}
llvm::BasicBlock *GenBlocks::walkExpr(llvm::BasicBlock *curblock,
Bexpression *expr)
{
// Visit children first
const std::vector<Bnode *> &kids = expr->children();
for (auto &child : kids)
curblock = walk(child, curblock);
// Now visit instructions for this expr
for (auto originst : expr->instructions()) {
if (!curblock) {
originst->deleteValue();
continue;
}
auto pair = postProcessInst(originst, curblock);
auto inst = pair.first;
if (createDebugMetaData_)
dibuildhelper().processExprInst(expr, inst);
curblock->getInstList().push_back(inst);
curblock = pair.second;
}
return curblock;
}
llvm::BasicBlock *GenBlocks::genIf(Bstatement *ifst,
llvm::BasicBlock *curblock)
{
assert(ifst->flavor() == N_IfStmt);
Bexpression *cond = ifst->getIfStmtCondition();
Bstatement *trueStmt = ifst->getIfStmtTrueBlock();
Bstatement *falseStmt = ifst->getIfStmtFalseBlock();
// Walk condition first
curblock = walkExpr(curblock, cond);
// Create true block
llvm::BasicBlock *tblock = mkLLVMBlock("then");
// Push fallthrough block
llvm::BasicBlock *ft = mkLLVMBlock("fallthrough");
// Create false block if present
llvm::BasicBlock *fblock = ft;
if (falseStmt)
fblock = mkLLVMBlock("else");
// Insert conditional branch into current block
llvm::Value *cval = cond->value();
llvm::BranchInst::Create(tblock, fblock, cval, curblock);
// Visit true block
llvm::BasicBlock *tsucc = walk(trueStmt, tblock);
if (tsucc && ! tsucc->getTerminator())
llvm::BranchInst::Create(ft, tsucc);
// Walk false block if present
if (falseStmt) {
llvm::BasicBlock *fsucc = walk(falseStmt, fblock);
if (fsucc && ! fsucc->getTerminator())
llvm::BranchInst::Create(ft, fsucc);
}
return ft;
}
llvm::BasicBlock *GenBlocks::genSwitch(Bstatement *swst,
llvm::BasicBlock *curblock)
{
assert(swst->flavor() == N_SwitchStmt);
// Walk switch value first
Bexpression *swval = swst->getSwitchStmtValue();
curblock = walkExpr(curblock, swval);
// Unpack switch
unsigned ncases = swst->getSwitchStmtNumCases();
// No need to walk switch value expressions -- they should all be constants.
// Create blocks
llvm::BasicBlock *defBB = nullptr;
std::vector<llvm::BasicBlock *> blocks(ncases);
for (unsigned idx = 0; idx < ncases; ++idx) {
std::vector<Bexpression *> thiscase =
swst->getSwitchStmtNthCase(idx);
bool isDefault = (thiscase.size() == 0);
std::string bname(isDefault ? "default" : "case");
blocks[idx] = mkLLVMBlock(bname);
if (isDefault) {
assert(! defBB);
defBB = blocks[idx];
}
}
llvm::BasicBlock *epilogBB = mkLLVMBlock("epilog");
if (!defBB)
defBB = epilogBB;
LIRBuilder builder(context_, llvm::ConstantFolder());
// Walk statement/block
for (unsigned idx = 0; idx < ncases; ++idx) {
Bstatement *st = swst->getSwitchStmtNthStmt(idx);
walk(st, blocks[idx]);
if (! blocks[idx]->getTerminator()) {
builder.SetInsertPoint(blocks[idx]);
builder.CreateBr(epilogBB);
}
}
// Create switch
builder.SetInsertPoint(curblock);
llvm::SwitchInst *swinst = builder.CreateSwitch(swval->value(), defBB);
// Connect values with blocks
for (unsigned idx = 0; idx < blocks.size(); ++idx) {
std::vector<Bexpression *> thiscase =
swst->getSwitchStmtNthCase(idx);
for (auto &exp : thiscase) {
llvm::ConstantInt *ci = llvm::cast<llvm::ConstantInt>(exp->value());
swinst->addCase(ci, blocks[idx]);
}
}
return epilogBB;
}
// In most cases a return statement is handled in canonical way,
// that is, any associated expressions are added to the current block
// (including an llvm::ReturnInst) and the current block is closed out.
//
// Special handling is needed when the return appears within a
// try/catch block (see Llvm_backend::exception_handler_statement)
// with a "finally" clause. In such cases we have to rewrite each
// return instruction into a jump to the finally block.
//
// HACK: we're taking advantage of the fact that the front end always
// stores return values to a local variable as opposed to returning
// those values directly (hence evern return sequence should always
// look like "return X" where X is a load from an appropriately typed
// variable. This fact permits us to copy a return from one place in
// the program to another while getting the same semantics.
llvm::BasicBlock *GenBlocks::genReturn(Bstatement *rst,
llvm::BasicBlock *curblock)
{
assert(rst->flavor() == N_ReturnStmt);
Bexpression *re = rst->getReturnStmtExpr();
if (finallyBlock_) {
// Rewrite the return to a jump into the 'finally' block (see above).
// Here we also cache away a return statement so as to relocate
// it after the 'finally' block.
if (cachedReturn_ == nullptr) {
// Steal this return.
cachedReturn_ = rst;
} else {
Bnode::destroy(re, DelInstructions);
}
llvm::BranchInst::Create(finallyBlock_, curblock);
} else {
// Walk return expression
llvm::BasicBlock *bb = walkExpr(curblock, re);
assert(curblock == bb);
}
// A return terminates the current block
return nullptr;
}
llvm::BasicBlock *GenBlocks::genDefer(Bstatement *defst,
llvm::BasicBlock *curblock)
{
assert(defst->flavor() == N_DeferStmt);
// Insure that current function has personality routine set.
llvm::Function *func = function()->function();
if (! func->hasPersonalityFn())
func->setPersonalityFn(be_->personalityFunction());
Bexpression *defcallex = defst->getDeferStmtDeferCall();
Bexpression *undcallex = defst->getDeferStmtUndeferCall();
// Finish bb (see the comments for Llvm_backend::function_defer_statement
// as to why we use this name).
llvm::BasicBlock *finbb =
llvm::BasicBlock::Create(context_, be_->namegen("finish"), func);
// Landing pad to which control will be transferred if an exception
// is thrown when executing "undcallex".
llvm::BasicBlock *padbb =
llvm::BasicBlock::Create(context_, be_->namegen("pad"), func);
// Catch BB will contain checkdefer (defercall) code.
llvm::BasicBlock *catchbb =
llvm::BasicBlock::Create(context_, be_->namegen("catch"), func);
if (curblock)
llvm::BranchInst::Create(finbb, curblock);
curblock = finbb;
// Push pad block onto stack. This will be an indication that any call
// in the undcallex subtree should be converted into an invoke with
// suitable landing pad.
padBlockStack_.push_back(padbb);
// Walk the undcall expression.
curblock = walkExpr(curblock, undcallex);
// Pop the pad block stack.
padBlockStack_.pop_back();
// Emit landing pad into pad block, followed by branch to catch block.
llvm::LandingPadInst *padinst =
llvm::LandingPadInst::Create(be_->landingPadExceptionType(),
0, be_->namegen("ex"), padbb);
padinst->addClause(llvm::Constant::getNullValue(be_->llvmPtrType()));
llvm::BranchInst::Create(catchbb, padbb);
llvm::BasicBlock *contbb = curblock;
// Catch block containing defer call.
curblock = catchbb;
auto bb = walkExpr(curblock, defcallex);
assert(bb == curblock);
llvm::BranchInst::Create(finbb, catchbb);
// Continue bb is final bb.
return contbb;
}
llvm::BasicBlock *GenBlocks::genExcep(Bstatement *excepst,
llvm::BasicBlock *curblock)
{
assert(excepst->flavor() == N_ExcepStmt);
// Insure that current function has personality set.
llvm::Function *func = function()->function();
if (! func->hasPersonalityFn())
func->setPersonalityFn(be_->personalityFunction());
Bstatement *body = excepst->getExcepStmtBody();
assert(body);
Bstatement *ifexception = excepst->getExcepStmtOnException();
assert(ifexception);
Bstatement *finally = excepst->getExcepStmtFinally(); // may be null
// Create a landing pad block. This pad will be where control
// will arrive if an exception is thrown within the "body" code.
llvm::BasicBlock *padbb =
llvm::BasicBlock::Create(context_, be_->namegen("pad"), func);
// Create a "finally" BB, corresponding to where control will wind
// up once both the body and (possibly) the exception clause are
// complete. This will also be where we'll place any code in the
// "finally" statement above.
std::string cbbname(be_->namegen("finally"));
llvm::BasicBlock *contbb =
llvm::BasicBlock::Create(context_, cbbname, func);
// Not expecting to see nested exception statements, assert if
// this crops up.
assert(padBlockStack_.empty());
// If there is a finally block, then record the block for purposes
// of return handling.
finallyBlock_ = (finally ? contbb : nullptr);
assert(!cachedReturn_);
// Push first pad block onto stack. The presence of a non-empty pad
// block stack will be an indication that any call in the body
// subtree should be converted into an invoke using the pad.
padBlockStack_.push_back(padbb);
// Walk the body statement.
curblock = walk(body, curblock);
// Pop the pad block stack.
padBlockStack_.pop_back();
// If the body block ended without a return, then insert a jump
// to the continue / or finally clause.
if (curblock)
llvm::BranchInst::Create(contbb, curblock);
// Emit landing pad inst in pad block, followed by branch to catch bb.
llvm::LandingPadInst *padinst =
llvm::LandingPadInst::Create(be_->landingPadExceptionType(),
0, be_->namegen("ex"), padbb);
padinst->addClause(llvm::Constant::getNullValue(be_->llvmPtrType()));
llvm::BasicBlock *catchbb =
llvm::BasicBlock::Create(context_, be_->namegen("catch"), func);
llvm::BranchInst::Create(catchbb, padbb);
// Create second pad block. Here the idea is that if an exception
// is thrown as a result of any call within the catch ("ifexception" code)
// it will wind up at this pad.
llvm::BasicBlock *catchpadbb =
llvm::BasicBlock::Create(context_, be_->namegen("catchpad"), func);
// Push second pad, walk exception stmt, then pop the pad.
padBlockStack_.push_back(catchpadbb);
auto bb = walk(ifexception, catchbb);
if (bb)
llvm::BranchInst::Create(contbb, bb);
padBlockStack_.pop_back();
// Return handling now complete.
finallyBlock_ = nullptr;
// Fix up second pad block, followed by branch to continue block.
llvm::LandingPadInst *padinst2 =
llvm::LandingPadInst::Create(be_->landingPadExceptionType(),
0, be_->namegen("ex2"), catchpadbb);
padinst2->addClause(llvm::Constant::getNullValue(be_->llvmPtrType()));
llvm::BranchInst::Create(contbb, catchpadbb);
// Handle finally statement where applicable.
curblock = contbb;
if (finally != nullptr) {
curblock = walk(finally, curblock);
if (cachedReturn_ != nullptr) {
Bexpression *re = cachedReturn_->getReturnStmtExpr();
llvm::BasicBlock *bb = walkExpr(curblock, re);
assert(curblock == bb);
cachedReturn_ = nullptr;
}
}
return curblock;
}
llvm::BasicBlock *GenBlocks::walk(Bnode *node,
llvm::BasicBlock *curblock)
{
Bexpression *expr = node->castToBexpression();
if (expr)
return walkExpr(curblock, expr);
llvm::Function *func = function()->function();
Bstatement *stmt = node->castToBstatement();
assert(stmt);
switch (stmt->flavor()) {
case N_ExprStmt: {
curblock = walkExpr(curblock, stmt->getExprStmtExpr());
break;
}
case N_BlockStmt: {
Bblock *bblock = stmt->castToBblock();
if (createDebugMetaData_)
dibuildhelper().beginLexicalBlock(bblock);
for (auto &st : stmt->getChildStmts())
curblock = walk(st, curblock);
if (createDebugMetaData_)
dibuildhelper().endLexicalBlock(bblock);
break;
}
case N_IfStmt: {
curblock = genIf(stmt, curblock);
break;
}
case N_SwitchStmt: {
curblock = genSwitch(stmt, curblock);
break;
}
case N_ReturnStmt: {
curblock = genReturn(stmt, curblock);
break;
}
case N_DeferStmt: {
curblock = genDefer(stmt, curblock);
break;
}
case N_ExcepStmt: {
curblock = genExcep(stmt, curblock);
break;
}
case N_GotoStmt: {
llvm::BasicBlock *lbb = getBlockForLabel(stmt->getGotoStmtTargetLabel());
if (curblock && ! curblock->getTerminator())
llvm::BranchInst::Create(lbb, curblock);
if (emitOrphanedCode_) {
std::string n = be_->namegen("orphan");
llvm::BasicBlock *orphan =
llvm::BasicBlock::Create(context_, n, func, lbb);
curblock = orphan;
} else {
curblock = nullptr;
}
break;
}
case N_LabelStmt: {
Blabel *label = stmt->getLabelStmtDefinedLabel();
llvm::BasicBlock *lbb = getBlockForLabel(label);
if (label->placeholder())
function()->replaceLabelAddressPlaceholder(label->placeholder(), lbb);
if (curblock)
llvm::BranchInst::Create(lbb, curblock);
curblock = lbb;
break;
}
default:
assert(false && "not yet handled");
}
return curblock;
}
llvm::BasicBlock *Llvm_backend::genEntryBlock(Bfunction *bfunction) {
llvm::Function *func = bfunction->function();
llvm::BasicBlock *entry = llvm::BasicBlock::Create(context_, "entry", func);
// Spill parameters/arguments, insert allocas for local vars
bfunction->genProlog(entry);
return entry;
}
void Llvm_backend::fixupEpilogBlock(Bfunction *bfunction,
llvm::BasicBlock *epilog)
{
// Append a return instruction if the block does not end with
// a control transfer.
if (epilog->empty() || !epilog->back().isTerminator()) {
LIRBuilder builder(context_, llvm::ConstantFolder());
llvm::Function *func = bfunction->function();
llvm::Type *rtyp= func->getFunctionType()->getReturnType();
llvm::ReturnInst *ri = nullptr;
if (rtyp->isVoidTy()) {
ri = builder.CreateRetVoid();
} else {
llvm::Value *zv = llvm::Constant::getNullValue(rtyp);
ri = builder.CreateRet(zv);
}
epilog->getInstList().push_back(ri);
}
}
// Set the function body for FUNCTION using the code in CODE_BLOCK.
bool Llvm_backend::function_set_body(Bfunction *function,
Bstatement *code_stmt)
{
if (function == errorFunction_.get())
return true;
// debugging
if (traceLevel() > 1) {
std::cerr << "Statement tree dump:\n";
code_stmt->dump();
}
// Invoke the tree integrity checker. We do this even if
// checkIntegrity_ is false so to deal with any repairable
// sharing that the front end may have introduced.
enforceTreeIntegrity(code_stmt);
// Create and populate entry block
llvm::BasicBlock *entryBlock = genEntryBlock(function);
// Avoid debug meta-generation if errors seen
bool dodebug = (createDebugMetaData_ && errorCount_ == 0);
// Walk the code statements
GenBlocks gb(context_, this, function, code_stmt,
getDICompUnit(), dodebug, entryBlock);
llvm::BasicBlock *block = gb.walk(code_stmt, entryBlock);
gb.finishFunction(entryBlock);
// Fix up epilog block if needed
if (block)
fixupEpilogBlock(function, block);
// debugging
if (traceLevel() > 0) {
std::cerr << "LLVM function dump:\n";
function->function()->dump();
}
return true;
}
// Write the definitions for all TYPE_DECLS, CONSTANT_DECLS,
// FUNCTION_DECLS, and VARIABLE_DECLS declared globally, as well as
// emit early debugging information.
void Llvm_backend::write_global_definitions(
const std::vector<Btype *> &type_decls,
const std::vector<Bexpression *> &constant_decls,
const std::vector<Bfunction *> &function_decls,
const std::vector<Bvariable *> &variable_decls) {
finalizeExportData();
// At the moment there isn't anything to do here with the
// inputs we're being passed.
}
// Post-process export data to escape quotes, etc, writing bytes
// to the specified stringstream.
static void postProcessExportDataChunk(const char *bytes,
unsigned int size,
std::stringstream &ss)
{
std::map<char, std::string> rewrites = { { '\\', "\\\\" },
{ '\0', "\\000" },
{ '\n', "\\n" },
{ '"', "\\\"" } };
for (unsigned idx = 0; idx < size; ++idx) {
const char byte = bytes[idx];
auto it = rewrites.find(byte);
if (it != rewrites.end())
ss << it->second;
else
ss << byte;
}
}
// Finalize export data.
void Llvm_backend::finalizeExportData()
{
// Calling this here, for lack of a better spot
if (dibuilder_.get())
dibuilder_->finalize();
assert(! exportDataFinalized_);
exportDataFinalized_ = true;
module().appendModuleInlineAsm("\t.text\n");
if (traceLevel() > 1) {
std::cerr << "Export data emitted:\n";
std::cerr << module().getModuleInlineAsm();
}
}
// This is called by the Go frontend proper to add data to the
// section containing Go export data.
void Llvm_backend::write_export_data(const char *bytes, unsigned int size)
{
// FIXME: this is hacky and currently very ELF-specific. Better to
// add real support in MC object file layer.
assert(! exportDataFinalized_);
if (! exportDataStarted_) {
exportDataStarted_ = true;
const char *preamble = "\t.section \".go_export\",\"e\",@progbits";
module().appendModuleInlineAsm(preamble);
}
std::stringstream ss;
ss << "\t.ascii \"";
postProcessExportDataChunk(bytes, size, ss);
ss << "\"\n";
module().appendModuleInlineAsm(ss.str());
}
// Convert an identifier for use in an error message.
// TODO(tham): scan the identifier to determine if contains
// only ASCII or printable UTF-8, then perform character set
// conversions if needed.
const char *go_localize_identifier(const char *ident) { return ident; }
// Return a new backend generator.
Backend *go_get_backend(llvm::LLVMContext &context) {
return new Llvm_backend(context, nullptr, nullptr);
}