blob: 997e972e0ad45a06cc1f9617d72c07ee2d7fa700 [file] [log] [blame]
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gc
import (
"bytes"
"fmt"
"html"
"os"
"strings"
"cmd/compile/internal/ssa"
"cmd/internal/obj"
"cmd/internal/sys"
)
var ssaEnabled = true
var ssaConfig *ssa.Config
var ssaExp ssaExport
func initssa() *ssa.Config {
ssaExp.unimplemented = false
ssaExp.mustImplement = true
if ssaConfig == nil {
ssaConfig = ssa.NewConfig(Thearch.LinkArch.Name, &ssaExp, Ctxt, Debug['N'] == 0)
if Thearch.LinkArch.Name == "386" {
ssaConfig.Set387(Thearch.Use387)
}
}
return ssaConfig
}
func shouldssa(fn *Node) bool {
switch Thearch.LinkArch.Name {
default:
// Only available for testing.
if os.Getenv("SSATEST") == "" {
return false
}
case "amd64", "amd64p32", "arm", "386", "arm64":
// Generally available.
}
if !ssaEnabled {
return false
}
// Environment variable control of SSA CG
// 1. IF GOSSAFUNC == current function name THEN
// compile this function with SSA and log output to ssa.html
// 2. IF GOSSAHASH == "" THEN
// compile this function (and everything else) with SSA
// 3. IF GOSSAHASH == "n" or "N"
// IF GOSSAPKG == current package name THEN
// compile this function (and everything in this package) with SSA
// ELSE
// use the old back end for this function.
// This is for compatibility with existing test harness and should go away.
// 4. IF GOSSAHASH is a suffix of the binary-rendered SHA1 hash of the function name THEN
// compile this function with SSA
// ELSE
// compile this function with the old back end.
// Plan is for 3 to be removed when the tests are revised.
// SSA is now default, and is disabled by setting
// GOSSAHASH to n or N, or selectively with strings of
// 0 and 1.
name := fn.Func.Nname.Sym.Name
funcname := os.Getenv("GOSSAFUNC")
if funcname != "" {
// If GOSSAFUNC is set, compile only that function.
return name == funcname
}
pkg := os.Getenv("GOSSAPKG")
if pkg != "" {
// If GOSSAPKG is set, compile only that package.
return localpkg.Name == pkg
}
return initssa().DebugHashMatch("GOSSAHASH", name)
}
// buildssa builds an SSA function.
func buildssa(fn *Node) *ssa.Func {
name := fn.Func.Nname.Sym.Name
printssa := name == os.Getenv("GOSSAFUNC")
if printssa {
fmt.Println("generating SSA for", name)
dumplist("buildssa-enter", fn.Func.Enter)
dumplist("buildssa-body", fn.Nbody)
dumplist("buildssa-exit", fn.Func.Exit)
}
var s state
s.pushLine(fn.Lineno)
defer s.popLine()
if fn.Func.Pragma&CgoUnsafeArgs != 0 {
s.cgoUnsafeArgs = true
}
if fn.Func.Pragma&Nowritebarrier != 0 {
s.noWB = true
}
defer func() {
if s.WBLineno != 0 {
fn.Func.WBLineno = s.WBLineno
}
}()
// TODO(khr): build config just once at the start of the compiler binary
ssaExp.log = printssa
s.config = initssa()
s.f = s.config.NewFunc()
s.f.Name = name
s.exitCode = fn.Func.Exit
s.panics = map[funcLine]*ssa.Block{}
if name == os.Getenv("GOSSAFUNC") {
// TODO: tempfile? it is handy to have the location
// of this file be stable, so you can just reload in the browser.
s.config.HTML = ssa.NewHTMLWriter("ssa.html", s.config, name)
// TODO: generate and print a mapping from nodes to values and blocks
}
defer func() {
if !printssa {
s.config.HTML.Close()
}
}()
// Allocate starting block
s.f.Entry = s.f.NewBlock(ssa.BlockPlain)
// Allocate starting values
s.labels = map[string]*ssaLabel{}
s.labeledNodes = map[*Node]*ssaLabel{}
s.startmem = s.entryNewValue0(ssa.OpInitMem, ssa.TypeMem)
s.sp = s.entryNewValue0(ssa.OpSP, Types[TUINTPTR]) // TODO: use generic pointer type (unsafe.Pointer?) instead
s.sb = s.entryNewValue0(ssa.OpSB, Types[TUINTPTR])
s.startBlock(s.f.Entry)
s.vars[&memVar] = s.startmem
s.varsyms = map[*Node]interface{}{}
// Generate addresses of local declarations
s.decladdrs = map[*Node]*ssa.Value{}
for _, n := range fn.Func.Dcl {
switch n.Class {
case PPARAM, PPARAMOUT:
aux := s.lookupSymbol(n, &ssa.ArgSymbol{Typ: n.Type, Node: n})
s.decladdrs[n] = s.entryNewValue1A(ssa.OpAddr, Ptrto(n.Type), aux, s.sp)
if n.Class == PPARAMOUT && s.canSSA(n) {
// Save ssa-able PPARAMOUT variables so we can
// store them back to the stack at the end of
// the function.
s.returns = append(s.returns, n)
}
if n.Class == PPARAM && s.canSSA(n) && n.Type.IsPtrShaped() {
s.ptrargs = append(s.ptrargs, n)
n.SetNotLiveAtEnd(true) // SSA takes care of this explicitly
}
case PAUTO:
// processed at each use, to prevent Addr coming
// before the decl.
case PAUTOHEAP:
// moved to heap - already handled by frontend
case PFUNC:
// local function - already handled by frontend
default:
s.Unimplementedf("local variable with class %s unimplemented", classnames[n.Class])
}
}
// Convert the AST-based IR to the SSA-based IR
s.stmts(fn.Func.Enter)
s.stmts(fn.Nbody)
// fallthrough to exit
if s.curBlock != nil {
s.pushLine(fn.Func.Endlineno)
s.exit()
s.popLine()
}
// Check that we used all labels
for name, lab := range s.labels {
if !lab.used() && !lab.reported {
yyerrorl(lab.defNode.Lineno, "label %v defined and not used", name)
lab.reported = true
}
if lab.used() && !lab.defined() && !lab.reported {
yyerrorl(lab.useNode.Lineno, "label %v not defined", name)
lab.reported = true
}
}
// Check any forward gotos. Non-forward gotos have already been checked.
for _, n := range s.fwdGotos {
lab := s.labels[n.Left.Sym.Name]
// If the label is undefined, we have already have printed an error.
if lab.defined() {
s.checkgoto(n, lab.defNode)
}
}
if nerrors > 0 {
s.f.Free()
return nil
}
prelinkNumvars := s.f.NumValues()
sparseDefState := s.locatePotentialPhiFunctions(fn)
// Link up variable uses to variable definitions
s.linkForwardReferences(sparseDefState)
if ssa.BuildStats > 0 {
s.f.LogStat("build", s.f.NumBlocks(), "blocks", prelinkNumvars, "vars_before",
s.f.NumValues(), "vars_after", prelinkNumvars*s.f.NumBlocks(), "ssa_phi_loc_cutoff_score")
}
// Don't carry reference this around longer than necessary
s.exitCode = Nodes{}
// Main call to ssa package to compile function
ssa.Compile(s.f)
return s.f
}
type state struct {
// configuration (arch) information
config *ssa.Config
// function we're building
f *ssa.Func
// labels and labeled control flow nodes (OFOR, OSWITCH, OSELECT) in f
labels map[string]*ssaLabel
labeledNodes map[*Node]*ssaLabel
// gotos that jump forward; required for deferred checkgoto calls
fwdGotos []*Node
// Code that must precede any return
// (e.g., copying value of heap-escaped paramout back to true paramout)
exitCode Nodes
// unlabeled break and continue statement tracking
breakTo *ssa.Block // current target for plain break statement
continueTo *ssa.Block // current target for plain continue statement
// current location where we're interpreting the AST
curBlock *ssa.Block
// variable assignments in the current block (map from variable symbol to ssa value)
// *Node is the unique identifier (an ONAME Node) for the variable.
vars map[*Node]*ssa.Value
// all defined variables at the end of each block. Indexed by block ID.
defvars []map[*Node]*ssa.Value
// addresses of PPARAM and PPARAMOUT variables.
decladdrs map[*Node]*ssa.Value
// symbols for PEXTERN, PAUTO and PPARAMOUT variables so they can be reused.
varsyms map[*Node]interface{}
// starting values. Memory, stack pointer, and globals pointer
startmem *ssa.Value
sp *ssa.Value
sb *ssa.Value
// line number stack. The current line number is top of stack
line []int32
// list of panic calls by function name and line number.
// Used to deduplicate panic calls.
panics map[funcLine]*ssa.Block
// list of FwdRef values.
fwdRefs []*ssa.Value
// list of PPARAMOUT (return) variables.
returns []*Node
// list of PPARAM SSA-able pointer-shaped args. We ensure these are live
// throughout the function to help users avoid premature finalizers.
ptrargs []*Node
cgoUnsafeArgs bool
noWB bool
WBLineno int32 // line number of first write barrier. 0=no write barriers
}
type funcLine struct {
f *Node
line int32
}
type ssaLabel struct {
target *ssa.Block // block identified by this label
breakTarget *ssa.Block // block to break to in control flow node identified by this label
continueTarget *ssa.Block // block to continue to in control flow node identified by this label
defNode *Node // label definition Node (OLABEL)
// Label use Node (OGOTO, OBREAK, OCONTINUE).
// Used only for error detection and reporting.
// There might be multiple uses, but we only need to track one.
useNode *Node
reported bool // reported indicates whether an error has already been reported for this label
}
// defined reports whether the label has a definition (OLABEL node).
func (l *ssaLabel) defined() bool { return l.defNode != nil }
// used reports whether the label has a use (OGOTO, OBREAK, or OCONTINUE node).
func (l *ssaLabel) used() bool { return l.useNode != nil }
// label returns the label associated with sym, creating it if necessary.
func (s *state) label(sym *Sym) *ssaLabel {
lab := s.labels[sym.Name]
if lab == nil {
lab = new(ssaLabel)
s.labels[sym.Name] = lab
}
return lab
}
func (s *state) Logf(msg string, args ...interface{}) { s.config.Logf(msg, args...) }
func (s *state) Log() bool { return s.config.Log() }
func (s *state) Fatalf(msg string, args ...interface{}) { s.config.Fatalf(s.peekLine(), msg, args...) }
func (s *state) Unimplementedf(msg string, args ...interface{}) {
s.config.Unimplementedf(s.peekLine(), msg, args...)
}
func (s *state) Warnl(line int32, msg string, args ...interface{}) { s.config.Warnl(line, msg, args...) }
func (s *state) Debug_checknil() bool { return s.config.Debug_checknil() }
var (
// dummy node for the memory variable
memVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "mem"}}
// dummy nodes for temporary variables
ptrVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "ptr"}}
lenVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "len"}}
newlenVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "newlen"}}
capVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "cap"}}
typVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "typ"}}
idataVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "idata"}}
okVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "ok"}}
deltaVar = Node{Op: ONAME, Class: Pxxx, Sym: &Sym{Name: "delta"}}
)
// startBlock sets the current block we're generating code in to b.
func (s *state) startBlock(b *ssa.Block) {
if s.curBlock != nil {
s.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
}
s.curBlock = b
s.vars = map[*Node]*ssa.Value{}
}
// endBlock marks the end of generating code for the current block.
// Returns the (former) current block. Returns nil if there is no current
// block, i.e. if no code flows to the current execution point.
func (s *state) endBlock() *ssa.Block {
b := s.curBlock
if b == nil {
return nil
}
for len(s.defvars) <= int(b.ID) {
s.defvars = append(s.defvars, nil)
}
s.defvars[b.ID] = s.vars
s.curBlock = nil
s.vars = nil
b.Line = s.peekLine()
return b
}
// pushLine pushes a line number on the line number stack.
func (s *state) pushLine(line int32) {
if line == 0 {
// the frontend may emit node with line number missing,
// use the parent line number in this case.
line = s.peekLine()
if Debug['K'] != 0 {
Warn("buildssa: line 0")
}
}
s.line = append(s.line, line)
}
// popLine pops the top of the line number stack.
func (s *state) popLine() {
s.line = s.line[:len(s.line)-1]
}
// peekLine peek the top of the line number stack.
func (s *state) peekLine() int32 {
return s.line[len(s.line)-1]
}
func (s *state) Error(msg string, args ...interface{}) {
yyerrorl(s.peekLine(), msg, args...)
}
// newValue0 adds a new value with no arguments to the current block.
func (s *state) newValue0(op ssa.Op, t ssa.Type) *ssa.Value {
return s.curBlock.NewValue0(s.peekLine(), op, t)
}
// newValue0A adds a new value with no arguments and an aux value to the current block.
func (s *state) newValue0A(op ssa.Op, t ssa.Type, aux interface{}) *ssa.Value {
return s.curBlock.NewValue0A(s.peekLine(), op, t, aux)
}
// newValue0I adds a new value with no arguments and an auxint value to the current block.
func (s *state) newValue0I(op ssa.Op, t ssa.Type, auxint int64) *ssa.Value {
return s.curBlock.NewValue0I(s.peekLine(), op, t, auxint)
}
// newValue1 adds a new value with one argument to the current block.
func (s *state) newValue1(op ssa.Op, t ssa.Type, arg *ssa.Value) *ssa.Value {
return s.curBlock.NewValue1(s.peekLine(), op, t, arg)
}
// newValue1A adds a new value with one argument and an aux value to the current block.
func (s *state) newValue1A(op ssa.Op, t ssa.Type, aux interface{}, arg *ssa.Value) *ssa.Value {
return s.curBlock.NewValue1A(s.peekLine(), op, t, aux, arg)
}
// newValue1I adds a new value with one argument and an auxint value to the current block.
func (s *state) newValue1I(op ssa.Op, t ssa.Type, aux int64, arg *ssa.Value) *ssa.Value {
return s.curBlock.NewValue1I(s.peekLine(), op, t, aux, arg)
}
// newValue2 adds a new value with two arguments to the current block.
func (s *state) newValue2(op ssa.Op, t ssa.Type, arg0, arg1 *ssa.Value) *ssa.Value {
return s.curBlock.NewValue2(s.peekLine(), op, t, arg0, arg1)
}
// newValue2I adds a new value with two arguments and an auxint value to the current block.
func (s *state) newValue2I(op ssa.Op, t ssa.Type, aux int64, arg0, arg1 *ssa.Value) *ssa.Value {
return s.curBlock.NewValue2I(s.peekLine(), op, t, aux, arg0, arg1)
}
// newValue3 adds a new value with three arguments to the current block.
func (s *state) newValue3(op ssa.Op, t ssa.Type, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
return s.curBlock.NewValue3(s.peekLine(), op, t, arg0, arg1, arg2)
}
// newValue3I adds a new value with three arguments and an auxint value to the current block.
func (s *state) newValue3I(op ssa.Op, t ssa.Type, aux int64, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
return s.curBlock.NewValue3I(s.peekLine(), op, t, aux, arg0, arg1, arg2)
}
// entryNewValue0 adds a new value with no arguments to the entry block.
func (s *state) entryNewValue0(op ssa.Op, t ssa.Type) *ssa.Value {
return s.f.Entry.NewValue0(s.peekLine(), op, t)
}
// entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
func (s *state) entryNewValue0A(op ssa.Op, t ssa.Type, aux interface{}) *ssa.Value {
return s.f.Entry.NewValue0A(s.peekLine(), op, t, aux)
}
// entryNewValue0I adds a new value with no arguments and an auxint value to the entry block.
func (s *state) entryNewValue0I(op ssa.Op, t ssa.Type, auxint int64) *ssa.Value {
return s.f.Entry.NewValue0I(s.peekLine(), op, t, auxint)
}
// entryNewValue1 adds a new value with one argument to the entry block.
func (s *state) entryNewValue1(op ssa.Op, t ssa.Type, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1(s.peekLine(), op, t, arg)
}
// entryNewValue1 adds a new value with one argument and an auxint value to the entry block.
func (s *state) entryNewValue1I(op ssa.Op, t ssa.Type, auxint int64, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1I(s.peekLine(), op, t, auxint, arg)
}
// entryNewValue1A adds a new value with one argument and an aux value to the entry block.
func (s *state) entryNewValue1A(op ssa.Op, t ssa.Type, aux interface{}, arg *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue1A(s.peekLine(), op, t, aux, arg)
}
// entryNewValue2 adds a new value with two arguments to the entry block.
func (s *state) entryNewValue2(op ssa.Op, t ssa.Type, arg0, arg1 *ssa.Value) *ssa.Value {
return s.f.Entry.NewValue2(s.peekLine(), op, t, arg0, arg1)
}
// const* routines add a new const value to the entry block.
func (s *state) constSlice(t ssa.Type) *ssa.Value { return s.f.ConstSlice(s.peekLine(), t) }
func (s *state) constInterface(t ssa.Type) *ssa.Value { return s.f.ConstInterface(s.peekLine(), t) }
func (s *state) constNil(t ssa.Type) *ssa.Value { return s.f.ConstNil(s.peekLine(), t) }
func (s *state) constEmptyString(t ssa.Type) *ssa.Value { return s.f.ConstEmptyString(s.peekLine(), t) }
func (s *state) constBool(c bool) *ssa.Value {
return s.f.ConstBool(s.peekLine(), Types[TBOOL], c)
}
func (s *state) constInt8(t ssa.Type, c int8) *ssa.Value {
return s.f.ConstInt8(s.peekLine(), t, c)
}
func (s *state) constInt16(t ssa.Type, c int16) *ssa.Value {
return s.f.ConstInt16(s.peekLine(), t, c)
}
func (s *state) constInt32(t ssa.Type, c int32) *ssa.Value {
return s.f.ConstInt32(s.peekLine(), t, c)
}
func (s *state) constInt64(t ssa.Type, c int64) *ssa.Value {
return s.f.ConstInt64(s.peekLine(), t, c)
}
func (s *state) constFloat32(t ssa.Type, c float64) *ssa.Value {
return s.f.ConstFloat32(s.peekLine(), t, c)
}
func (s *state) constFloat64(t ssa.Type, c float64) *ssa.Value {
return s.f.ConstFloat64(s.peekLine(), t, c)
}
func (s *state) constInt(t ssa.Type, c int64) *ssa.Value {
if s.config.IntSize == 8 {
return s.constInt64(t, c)
}
if int64(int32(c)) != c {
s.Fatalf("integer constant too big %d", c)
}
return s.constInt32(t, int32(c))
}
func (s *state) stmts(a Nodes) {
for _, x := range a.Slice() {
s.stmt(x)
}
}
// ssaStmtList converts the statement n to SSA and adds it to s.
func (s *state) stmtList(l Nodes) {
for _, n := range l.Slice() {
s.stmt(n)
}
}
// ssaStmt converts the statement n to SSA and adds it to s.
func (s *state) stmt(n *Node) {
s.pushLine(n.Lineno)
defer s.popLine()
// If s.curBlock is nil, then we're about to generate dead code.
// We can't just short-circuit here, though,
// because we check labels and gotos as part of SSA generation.
// Provide a block for the dead code so that we don't have
// to add special cases everywhere else.
if s.curBlock == nil {
dead := s.f.NewBlock(ssa.BlockPlain)
s.startBlock(dead)
}
s.stmtList(n.Ninit)
switch n.Op {
case OBLOCK:
s.stmtList(n.List)
// No-ops
case OEMPTY, ODCLCONST, ODCLTYPE, OFALL:
// Expression statements
case OCALLFUNC, OCALLMETH, OCALLINTER:
s.call(n, callNormal)
if n.Op == OCALLFUNC && n.Left.Op == ONAME && n.Left.Class == PFUNC &&
(compiling_runtime && n.Left.Sym.Name == "throw" ||
n.Left.Sym.Pkg == Runtimepkg && (n.Left.Sym.Name == "gopanic" || n.Left.Sym.Name == "selectgo" || n.Left.Sym.Name == "block")) {
m := s.mem()
b := s.endBlock()
b.Kind = ssa.BlockExit
b.SetControl(m)
// TODO: never rewrite OPANIC to OCALLFUNC in the
// first place. Need to wait until all backends
// go through SSA.
}
case ODEFER:
s.call(n.Left, callDefer)
case OPROC:
s.call(n.Left, callGo)
case OAS2DOTTYPE:
res, resok := s.dottype(n.Rlist.First(), true)
s.assign(n.List.First(), res, needwritebarrier(n.List.First(), n.Rlist.First()), false, n.Lineno, 0, false)
s.assign(n.List.Second(), resok, false, false, n.Lineno, 0, false)
return
case ODCL:
if n.Left.Class == PAUTOHEAP {
Fatalf("DCL %v", n)
}
case OLABEL:
sym := n.Left.Sym
if isblanksym(sym) {
// Empty identifier is valid but useless.
// See issues 11589, 11593.
return
}
lab := s.label(sym)
// Associate label with its control flow node, if any
if ctl := n.Name.Defn; ctl != nil {
switch ctl.Op {
case OFOR, OSWITCH, OSELECT:
s.labeledNodes[ctl] = lab
}
}
if !lab.defined() {
lab.defNode = n
} else {
s.Error("label %v already defined at %v", sym, linestr(lab.defNode.Lineno))
lab.reported = true
}
// The label might already have a target block via a goto.
if lab.target == nil {
lab.target = s.f.NewBlock(ssa.BlockPlain)
}
// go to that label (we pretend "label:" is preceded by "goto label")
b := s.endBlock()
b.AddEdgeTo(lab.target)
s.startBlock(lab.target)
case OGOTO:
sym := n.Left.Sym
lab := s.label(sym)
if lab.target == nil {
lab.target = s.f.NewBlock(ssa.BlockPlain)
}
if !lab.used() {
lab.useNode = n
}
if lab.defined() {
s.checkgoto(n, lab.defNode)
} else {
s.fwdGotos = append(s.fwdGotos, n)
}
b := s.endBlock()
b.AddEdgeTo(lab.target)
case OAS, OASWB:
// Check whether we can generate static data rather than code.
// If so, ignore n and defer data generation until codegen.
// Failure to do this causes writes to readonly symbols.
if gen_as_init(n, true) {
var data []*Node
if s.f.StaticData != nil {
data = s.f.StaticData.([]*Node)
}
s.f.StaticData = append(data, n)
return
}
if n.Left == n.Right && n.Left.Op == ONAME {
// An x=x assignment. No point in doing anything
// here. In addition, skipping this assignment
// prevents generating:
// VARDEF x
// COPY x -> x
// which is bad because x is incorrectly considered
// dead before the vardef. See issue #14904.
return
}
var t *Type
if n.Right != nil {
t = n.Right.Type
} else {
t = n.Left.Type
}
// Evaluate RHS.
rhs := n.Right
if rhs != nil {
switch rhs.Op {
case OSTRUCTLIT, OARRAYLIT:
// All literals with nonzero fields have already been
// rewritten during walk. Any that remain are just T{}
// or equivalents. Use the zero value.
if !iszero(rhs) {
Fatalf("literal with nonzero value in SSA: %v", rhs)
}
rhs = nil
case OAPPEND:
// If we're writing the result of an append back to the same slice,
// handle it specially to avoid write barriers on the fast (non-growth) path.
// If the slice can be SSA'd, it'll be on the stack,
// so there will be no write barriers,
// so there's no need to attempt to prevent them.
if samesafeexpr(n.Left, rhs.List.First()) && !s.canSSA(n.Left) {
s.append(rhs, true)
return
}
}
}
var r *ssa.Value
var isVolatile bool
needwb := n.Op == OASWB && rhs != nil
deref := !canSSAType(t)
if deref {
if rhs == nil {
r = nil // Signal assign to use OpZero.
} else {
r, isVolatile = s.addr(rhs, false)
}
} else {
if rhs == nil {
r = s.zeroVal(t)
} else {
r = s.expr(rhs)
}
}
if rhs != nil && rhs.Op == OAPPEND {
// The frontend gets rid of the write barrier to enable the special OAPPEND
// handling above, but since this is not a special case, we need it.
// TODO: just add a ptr graying to the end of growslice?
// TODO: check whether we need to provide special handling and a write barrier
// for ODOTTYPE and ORECV also.
// They get similar wb-removal treatment in walk.go:OAS.
needwb = true
}
var skip skipMask
if rhs != nil && (rhs.Op == OSLICE || rhs.Op == OSLICE3 || rhs.Op == OSLICESTR) && samesafeexpr(rhs.Left, n.Left) {
// We're assigning a slicing operation back to its source.
// Don't write back fields we aren't changing. See issue #14855.
i, j, k := rhs.SliceBounds()
if i != nil && (i.Op == OLITERAL && i.Val().Ctype() == CTINT && i.Int64() == 0) {
// [0:...] is the same as [:...]
i = nil
}
// TODO: detect defaults for len/cap also.
// Currently doesn't really work because (*p)[:len(*p)] appears here as:
// tmp = len(*p)
// (*p)[:tmp]
//if j != nil && (j.Op == OLEN && samesafeexpr(j.Left, n.Left)) {
// j = nil
//}
//if k != nil && (k.Op == OCAP && samesafeexpr(k.Left, n.Left)) {
// k = nil
//}
if i == nil {
skip |= skipPtr
if j == nil {
skip |= skipLen
}
if k == nil {
skip |= skipCap
}
}
}
s.assign(n.Left, r, needwb, deref, n.Lineno, skip, isVolatile)
case OIF:
bThen := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
var bElse *ssa.Block
if n.Rlist.Len() != 0 {
bElse = s.f.NewBlock(ssa.BlockPlain)
s.condBranch(n.Left, bThen, bElse, n.Likely)
} else {
s.condBranch(n.Left, bThen, bEnd, n.Likely)
}
s.startBlock(bThen)
s.stmts(n.Nbody)
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bEnd)
}
if n.Rlist.Len() != 0 {
s.startBlock(bElse)
s.stmtList(n.Rlist)
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bEnd)
}
}
s.startBlock(bEnd)
case ORETURN:
s.stmtList(n.List)
s.exit()
case ORETJMP:
s.stmtList(n.List)
b := s.exit()
b.Kind = ssa.BlockRetJmp // override BlockRet
b.Aux = n.Left.Sym
case OCONTINUE, OBREAK:
var op string
var to *ssa.Block
switch n.Op {
case OCONTINUE:
op = "continue"
to = s.continueTo
case OBREAK:
op = "break"
to = s.breakTo
}
if n.Left == nil {
// plain break/continue
if to == nil {
s.Error("%s is not in a loop", op)
return
}
// nothing to do; "to" is already the correct target
} else {
// labeled break/continue; look up the target
sym := n.Left.Sym
lab := s.label(sym)
if !lab.used() {
lab.useNode = n.Left
}
if !lab.defined() {
s.Error("%s label not defined: %v", op, sym)
lab.reported = true
return
}
switch n.Op {
case OCONTINUE:
to = lab.continueTarget
case OBREAK:
to = lab.breakTarget
}
if to == nil {
// Valid label but not usable with a break/continue here, e.g.:
// for {
// continue abc
// }
// abc:
// for {}
s.Error("invalid %s label %v", op, sym)
lab.reported = true
return
}
}
b := s.endBlock()
b.AddEdgeTo(to)
case OFOR:
// OFOR: for Ninit; Left; Right { Nbody }
bCond := s.f.NewBlock(ssa.BlockPlain)
bBody := s.f.NewBlock(ssa.BlockPlain)
bIncr := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
// first, jump to condition test
b := s.endBlock()
b.AddEdgeTo(bCond)
// generate code to test condition
s.startBlock(bCond)
if n.Left != nil {
s.condBranch(n.Left, bBody, bEnd, 1)
} else {
b := s.endBlock()
b.Kind = ssa.BlockPlain
b.AddEdgeTo(bBody)
}
// set up for continue/break in body
prevContinue := s.continueTo
prevBreak := s.breakTo
s.continueTo = bIncr
s.breakTo = bEnd
lab := s.labeledNodes[n]
if lab != nil {
// labeled for loop
lab.continueTarget = bIncr
lab.breakTarget = bEnd
}
// generate body
s.startBlock(bBody)
s.stmts(n.Nbody)
// tear down continue/break
s.continueTo = prevContinue
s.breakTo = prevBreak
if lab != nil {
lab.continueTarget = nil
lab.breakTarget = nil
}
// done with body, goto incr
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bIncr)
}
// generate incr
s.startBlock(bIncr)
if n.Right != nil {
s.stmt(n.Right)
}
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bCond)
}
s.startBlock(bEnd)
case OSWITCH, OSELECT:
// These have been mostly rewritten by the front end into their Nbody fields.
// Our main task is to correctly hook up any break statements.
bEnd := s.f.NewBlock(ssa.BlockPlain)
prevBreak := s.breakTo
s.breakTo = bEnd
lab := s.labeledNodes[n]
if lab != nil {
// labeled
lab.breakTarget = bEnd
}
// generate body code
s.stmts(n.Nbody)
s.breakTo = prevBreak
if lab != nil {
lab.breakTarget = nil
}
// OSWITCH never falls through (s.curBlock == nil here).
// OSELECT does not fall through if we're calling selectgo.
// OSELECT does fall through if we're calling selectnb{send,recv}[2].
// In those latter cases, go to the code after the select.
if b := s.endBlock(); b != nil {
b.AddEdgeTo(bEnd)
}
s.startBlock(bEnd)
case OVARKILL:
// Insert a varkill op to record that a variable is no longer live.
// We only care about liveness info at call sites, so putting the
// varkill in the store chain is enough to keep it correctly ordered
// with respect to call ops.
if !s.canSSA(n.Left) {
s.vars[&memVar] = s.newValue1A(ssa.OpVarKill, ssa.TypeMem, n.Left, s.mem())
}
case OVARLIVE:
// Insert a varlive op to record that a variable is still live.
if !n.Left.Addrtaken {
s.Fatalf("VARLIVE variable %s must have Addrtaken set", n.Left)
}
s.vars[&memVar] = s.newValue1A(ssa.OpVarLive, ssa.TypeMem, n.Left, s.mem())
case OCHECKNIL:
p := s.expr(n.Left)
s.nilCheck(p)
default:
s.Unimplementedf("unhandled stmt %s", n.Op)
}
}
// exit processes any code that needs to be generated just before returning.
// It returns a BlockRet block that ends the control flow. Its control value
// will be set to the final memory state.
func (s *state) exit() *ssa.Block {
if hasdefer {
s.rtcall(Deferreturn, true, nil)
}
// Run exit code. Typically, this code copies heap-allocated PPARAMOUT
// variables back to the stack.
s.stmts(s.exitCode)
// Store SSAable PPARAMOUT variables back to stack locations.
for _, n := range s.returns {
addr := s.decladdrs[n]
val := s.variable(n, n.Type)
s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, n, s.mem())
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, n.Type.Size(), addr, val, s.mem())
// TODO: if val is ever spilled, we'd like to use the
// PPARAMOUT slot for spilling it. That won't happen
// currently.
}
// Keep input pointer args live until the return. This is a bandaid
// fix for 1.7 for what will become in 1.8 explicit runtime.KeepAlive calls.
// For <= 1.7 we guarantee that pointer input arguments live to the end of
// the function to prevent premature (from the user's point of view)
// execution of finalizers. See issue 15277.
// TODO: remove for 1.8?
for _, n := range s.ptrargs {
s.vars[&memVar] = s.newValue2(ssa.OpKeepAlive, ssa.TypeMem, s.variable(n, n.Type), s.mem())
}
// Do actual return.
m := s.mem()
b := s.endBlock()
b.Kind = ssa.BlockRet
b.SetControl(m)
return b
}
type opAndType struct {
op Op
etype EType
}
var opToSSA = map[opAndType]ssa.Op{
opAndType{OADD, TINT8}: ssa.OpAdd8,
opAndType{OADD, TUINT8}: ssa.OpAdd8,
opAndType{OADD, TINT16}: ssa.OpAdd16,
opAndType{OADD, TUINT16}: ssa.OpAdd16,
opAndType{OADD, TINT32}: ssa.OpAdd32,
opAndType{OADD, TUINT32}: ssa.OpAdd32,
opAndType{OADD, TPTR32}: ssa.OpAdd32,
opAndType{OADD, TINT64}: ssa.OpAdd64,
opAndType{OADD, TUINT64}: ssa.OpAdd64,
opAndType{OADD, TPTR64}: ssa.OpAdd64,
opAndType{OADD, TFLOAT32}: ssa.OpAdd32F,
opAndType{OADD, TFLOAT64}: ssa.OpAdd64F,
opAndType{OSUB, TINT8}: ssa.OpSub8,
opAndType{OSUB, TUINT8}: ssa.OpSub8,
opAndType{OSUB, TINT16}: ssa.OpSub16,
opAndType{OSUB, TUINT16}: ssa.OpSub16,
opAndType{OSUB, TINT32}: ssa.OpSub32,
opAndType{OSUB, TUINT32}: ssa.OpSub32,
opAndType{OSUB, TINT64}: ssa.OpSub64,
opAndType{OSUB, TUINT64}: ssa.OpSub64,
opAndType{OSUB, TFLOAT32}: ssa.OpSub32F,
opAndType{OSUB, TFLOAT64}: ssa.OpSub64F,
opAndType{ONOT, TBOOL}: ssa.OpNot,
opAndType{OMINUS, TINT8}: ssa.OpNeg8,
opAndType{OMINUS, TUINT8}: ssa.OpNeg8,
opAndType{OMINUS, TINT16}: ssa.OpNeg16,
opAndType{OMINUS, TUINT16}: ssa.OpNeg16,
opAndType{OMINUS, TINT32}: ssa.OpNeg32,
opAndType{OMINUS, TUINT32}: ssa.OpNeg32,
opAndType{OMINUS, TINT64}: ssa.OpNeg64,
opAndType{OMINUS, TUINT64}: ssa.OpNeg64,
opAndType{OMINUS, TFLOAT32}: ssa.OpNeg32F,
opAndType{OMINUS, TFLOAT64}: ssa.OpNeg64F,
opAndType{OCOM, TINT8}: ssa.OpCom8,
opAndType{OCOM, TUINT8}: ssa.OpCom8,
opAndType{OCOM, TINT16}: ssa.OpCom16,
opAndType{OCOM, TUINT16}: ssa.OpCom16,
opAndType{OCOM, TINT32}: ssa.OpCom32,
opAndType{OCOM, TUINT32}: ssa.OpCom32,
opAndType{OCOM, TINT64}: ssa.OpCom64,
opAndType{OCOM, TUINT64}: ssa.OpCom64,
opAndType{OIMAG, TCOMPLEX64}: ssa.OpComplexImag,
opAndType{OIMAG, TCOMPLEX128}: ssa.OpComplexImag,
opAndType{OREAL, TCOMPLEX64}: ssa.OpComplexReal,
opAndType{OREAL, TCOMPLEX128}: ssa.OpComplexReal,
opAndType{OMUL, TINT8}: ssa.OpMul8,
opAndType{OMUL, TUINT8}: ssa.OpMul8,
opAndType{OMUL, TINT16}: ssa.OpMul16,
opAndType{OMUL, TUINT16}: ssa.OpMul16,
opAndType{OMUL, TINT32}: ssa.OpMul32,
opAndType{OMUL, TUINT32}: ssa.OpMul32,
opAndType{OMUL, TINT64}: ssa.OpMul64,
opAndType{OMUL, TUINT64}: ssa.OpMul64,
opAndType{OMUL, TFLOAT32}: ssa.OpMul32F,
opAndType{OMUL, TFLOAT64}: ssa.OpMul64F,
opAndType{ODIV, TFLOAT32}: ssa.OpDiv32F,
opAndType{ODIV, TFLOAT64}: ssa.OpDiv64F,
opAndType{OHMUL, TINT8}: ssa.OpHmul8,
opAndType{OHMUL, TUINT8}: ssa.OpHmul8u,
opAndType{OHMUL, TINT16}: ssa.OpHmul16,
opAndType{OHMUL, TUINT16}: ssa.OpHmul16u,
opAndType{OHMUL, TINT32}: ssa.OpHmul32,
opAndType{OHMUL, TUINT32}: ssa.OpHmul32u,
opAndType{ODIV, TINT8}: ssa.OpDiv8,
opAndType{ODIV, TUINT8}: ssa.OpDiv8u,
opAndType{ODIV, TINT16}: ssa.OpDiv16,
opAndType{ODIV, TUINT16}: ssa.OpDiv16u,
opAndType{ODIV, TINT32}: ssa.OpDiv32,
opAndType{ODIV, TUINT32}: ssa.OpDiv32u,
opAndType{ODIV, TINT64}: ssa.OpDiv64,
opAndType{ODIV, TUINT64}: ssa.OpDiv64u,
opAndType{OMOD, TINT8}: ssa.OpMod8,
opAndType{OMOD, TUINT8}: ssa.OpMod8u,
opAndType{OMOD, TINT16}: ssa.OpMod16,
opAndType{OMOD, TUINT16}: ssa.OpMod16u,
opAndType{OMOD, TINT32}: ssa.OpMod32,
opAndType{OMOD, TUINT32}: ssa.OpMod32u,
opAndType{OMOD, TINT64}: ssa.OpMod64,
opAndType{OMOD, TUINT64}: ssa.OpMod64u,
opAndType{OAND, TINT8}: ssa.OpAnd8,
opAndType{OAND, TUINT8}: ssa.OpAnd8,
opAndType{OAND, TINT16}: ssa.OpAnd16,
opAndType{OAND, TUINT16}: ssa.OpAnd16,
opAndType{OAND, TINT32}: ssa.OpAnd32,
opAndType{OAND, TUINT32}: ssa.OpAnd32,
opAndType{OAND, TINT64}: ssa.OpAnd64,
opAndType{OAND, TUINT64}: ssa.OpAnd64,
opAndType{OOR, TINT8}: ssa.OpOr8,
opAndType{OOR, TUINT8}: ssa.OpOr8,
opAndType{OOR, TINT16}: ssa.OpOr16,
opAndType{OOR, TUINT16}: ssa.OpOr16,
opAndType{OOR, TINT32}: ssa.OpOr32,
opAndType{OOR, TUINT32}: ssa.OpOr32,
opAndType{OOR, TINT64}: ssa.OpOr64,
opAndType{OOR, TUINT64}: ssa.OpOr64,
opAndType{OXOR, TINT8}: ssa.OpXor8,
opAndType{OXOR, TUINT8}: ssa.OpXor8,
opAndType{OXOR, TINT16}: ssa.OpXor16,
opAndType{OXOR, TUINT16}: ssa.OpXor16,
opAndType{OXOR, TINT32}: ssa.OpXor32,
opAndType{OXOR, TUINT32}: ssa.OpXor32,
opAndType{OXOR, TINT64}: ssa.OpXor64,
opAndType{OXOR, TUINT64}: ssa.OpXor64,
opAndType{OEQ, TBOOL}: ssa.OpEqB,
opAndType{OEQ, TINT8}: ssa.OpEq8,
opAndType{OEQ, TUINT8}: ssa.OpEq8,
opAndType{OEQ, TINT16}: ssa.OpEq16,
opAndType{OEQ, TUINT16}: ssa.OpEq16,
opAndType{OEQ, TINT32}: ssa.OpEq32,
opAndType{OEQ, TUINT32}: ssa.OpEq32,
opAndType{OEQ, TINT64}: ssa.OpEq64,
opAndType{OEQ, TUINT64}: ssa.OpEq64,
opAndType{OEQ, TINTER}: ssa.OpEqInter,
opAndType{OEQ, TSLICE}: ssa.OpEqSlice,
opAndType{OEQ, TFUNC}: ssa.OpEqPtr,
opAndType{OEQ, TMAP}: ssa.OpEqPtr,
opAndType{OEQ, TCHAN}: ssa.OpEqPtr,
opAndType{OEQ, TPTR32}: ssa.OpEqPtr,
opAndType{OEQ, TPTR64}: ssa.OpEqPtr,
opAndType{OEQ, TUINTPTR}: ssa.OpEqPtr,
opAndType{OEQ, TUNSAFEPTR}: ssa.OpEqPtr,
opAndType{OEQ, TFLOAT64}: ssa.OpEq64F,
opAndType{OEQ, TFLOAT32}: ssa.OpEq32F,
opAndType{ONE, TBOOL}: ssa.OpNeqB,
opAndType{ONE, TINT8}: ssa.OpNeq8,
opAndType{ONE, TUINT8}: ssa.OpNeq8,
opAndType{ONE, TINT16}: ssa.OpNeq16,
opAndType{ONE, TUINT16}: ssa.OpNeq16,
opAndType{ONE, TINT32}: ssa.OpNeq32,
opAndType{ONE, TUINT32}: ssa.OpNeq32,
opAndType{ONE, TINT64}: ssa.OpNeq64,
opAndType{ONE, TUINT64}: ssa.OpNeq64,
opAndType{ONE, TINTER}: ssa.OpNeqInter,
opAndType{ONE, TSLICE}: ssa.OpNeqSlice,
opAndType{ONE, TFUNC}: ssa.OpNeqPtr,
opAndType{ONE, TMAP}: ssa.OpNeqPtr,
opAndType{ONE, TCHAN}: ssa.OpNeqPtr,
opAndType{ONE, TPTR32}: ssa.OpNeqPtr,
opAndType{ONE, TPTR64}: ssa.OpNeqPtr,
opAndType{ONE, TUINTPTR}: ssa.OpNeqPtr,
opAndType{ONE, TUNSAFEPTR}: ssa.OpNeqPtr,
opAndType{ONE, TFLOAT64}: ssa.OpNeq64F,
opAndType{ONE, TFLOAT32}: ssa.OpNeq32F,
opAndType{OLT, TINT8}: ssa.OpLess8,
opAndType{OLT, TUINT8}: ssa.OpLess8U,
opAndType{OLT, TINT16}: ssa.OpLess16,
opAndType{OLT, TUINT16}: ssa.OpLess16U,
opAndType{OLT, TINT32}: ssa.OpLess32,
opAndType{OLT, TUINT32}: ssa.OpLess32U,
opAndType{OLT, TINT64}: ssa.OpLess64,
opAndType{OLT, TUINT64}: ssa.OpLess64U,
opAndType{OLT, TFLOAT64}: ssa.OpLess64F,
opAndType{OLT, TFLOAT32}: ssa.OpLess32F,
opAndType{OGT, TINT8}: ssa.OpGreater8,
opAndType{OGT, TUINT8}: ssa.OpGreater8U,
opAndType{OGT, TINT16}: ssa.OpGreater16,
opAndType{OGT, TUINT16}: ssa.OpGreater16U,
opAndType{OGT, TINT32}: ssa.OpGreater32,
opAndType{OGT, TUINT32}: ssa.OpGreater32U,
opAndType{OGT, TINT64}: ssa.OpGreater64,
opAndType{OGT, TUINT64}: ssa.OpGreater64U,
opAndType{OGT, TFLOAT64}: ssa.OpGreater64F,
opAndType{OGT, TFLOAT32}: ssa.OpGreater32F,
opAndType{OLE, TINT8}: ssa.OpLeq8,
opAndType{OLE, TUINT8}: ssa.OpLeq8U,
opAndType{OLE, TINT16}: ssa.OpLeq16,
opAndType{OLE, TUINT16}: ssa.OpLeq16U,
opAndType{OLE, TINT32}: ssa.OpLeq32,
opAndType{OLE, TUINT32}: ssa.OpLeq32U,
opAndType{OLE, TINT64}: ssa.OpLeq64,
opAndType{OLE, TUINT64}: ssa.OpLeq64U,
opAndType{OLE, TFLOAT64}: ssa.OpLeq64F,
opAndType{OLE, TFLOAT32}: ssa.OpLeq32F,
opAndType{OGE, TINT8}: ssa.OpGeq8,
opAndType{OGE, TUINT8}: ssa.OpGeq8U,
opAndType{OGE, TINT16}: ssa.OpGeq16,
opAndType{OGE, TUINT16}: ssa.OpGeq16U,
opAndType{OGE, TINT32}: ssa.OpGeq32,
opAndType{OGE, TUINT32}: ssa.OpGeq32U,
opAndType{OGE, TINT64}: ssa.OpGeq64,
opAndType{OGE, TUINT64}: ssa.OpGeq64U,
opAndType{OGE, TFLOAT64}: ssa.OpGeq64F,
opAndType{OGE, TFLOAT32}: ssa.OpGeq32F,
opAndType{OLROT, TUINT8}: ssa.OpLrot8,
opAndType{OLROT, TUINT16}: ssa.OpLrot16,
opAndType{OLROT, TUINT32}: ssa.OpLrot32,
opAndType{OLROT, TUINT64}: ssa.OpLrot64,
opAndType{OSQRT, TFLOAT64}: ssa.OpSqrt,
}
func (s *state) concreteEtype(t *Type) EType {
e := t.Etype
switch e {
default:
return e
case TINT:
if s.config.IntSize == 8 {
return TINT64
}
return TINT32
case TUINT:
if s.config.IntSize == 8 {
return TUINT64
}
return TUINT32
case TUINTPTR:
if s.config.PtrSize == 8 {
return TUINT64
}
return TUINT32
}
}
func (s *state) ssaOp(op Op, t *Type) ssa.Op {
etype := s.concreteEtype(t)
x, ok := opToSSA[opAndType{op, etype}]
if !ok {
s.Unimplementedf("unhandled binary op %s %s", op, etype)
}
return x
}
func floatForComplex(t *Type) *Type {
if t.Size() == 8 {
return Types[TFLOAT32]
} else {
return Types[TFLOAT64]
}
}
type opAndTwoTypes struct {
op Op
etype1 EType
etype2 EType
}
type twoTypes struct {
etype1 EType
etype2 EType
}
type twoOpsAndType struct {
op1 ssa.Op
op2 ssa.Op
intermediateType EType
}
var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
twoTypes{TINT8, TFLOAT32}: twoOpsAndType{ssa.OpSignExt8to32, ssa.OpCvt32to32F, TINT32},
twoTypes{TINT16, TFLOAT32}: twoOpsAndType{ssa.OpSignExt16to32, ssa.OpCvt32to32F, TINT32},
twoTypes{TINT32, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32to32F, TINT32},
twoTypes{TINT64, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt64to32F, TINT64},
twoTypes{TINT8, TFLOAT64}: twoOpsAndType{ssa.OpSignExt8to32, ssa.OpCvt32to64F, TINT32},
twoTypes{TINT16, TFLOAT64}: twoOpsAndType{ssa.OpSignExt16to32, ssa.OpCvt32to64F, TINT32},
twoTypes{TINT32, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32to64F, TINT32},
twoTypes{TINT64, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt64to64F, TINT64},
twoTypes{TFLOAT32, TINT8}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to8, TINT32},
twoTypes{TFLOAT32, TINT16}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to16, TINT32},
twoTypes{TFLOAT32, TINT32}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpCopy, TINT32},
twoTypes{TFLOAT32, TINT64}: twoOpsAndType{ssa.OpCvt32Fto64, ssa.OpCopy, TINT64},
twoTypes{TFLOAT64, TINT8}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to8, TINT32},
twoTypes{TFLOAT64, TINT16}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to16, TINT32},
twoTypes{TFLOAT64, TINT32}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpCopy, TINT32},
twoTypes{TFLOAT64, TINT64}: twoOpsAndType{ssa.OpCvt64Fto64, ssa.OpCopy, TINT64},
// unsigned
twoTypes{TUINT8, TFLOAT32}: twoOpsAndType{ssa.OpZeroExt8to32, ssa.OpCvt32to32F, TINT32},
twoTypes{TUINT16, TFLOAT32}: twoOpsAndType{ssa.OpZeroExt16to32, ssa.OpCvt32to32F, TINT32},
twoTypes{TUINT32, TFLOAT32}: twoOpsAndType{ssa.OpZeroExt32to64, ssa.OpCvt64to32F, TINT64}, // go wide to dodge unsigned
twoTypes{TUINT64, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpInvalid, TUINT64}, // Cvt64Uto32F, branchy code expansion instead
twoTypes{TUINT8, TFLOAT64}: twoOpsAndType{ssa.OpZeroExt8to32, ssa.OpCvt32to64F, TINT32},
twoTypes{TUINT16, TFLOAT64}: twoOpsAndType{ssa.OpZeroExt16to32, ssa.OpCvt32to64F, TINT32},
twoTypes{TUINT32, TFLOAT64}: twoOpsAndType{ssa.OpZeroExt32to64, ssa.OpCvt64to64F, TINT64}, // go wide to dodge unsigned
twoTypes{TUINT64, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpInvalid, TUINT64}, // Cvt64Uto64F, branchy code expansion instead
twoTypes{TFLOAT32, TUINT8}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to8, TINT32},
twoTypes{TFLOAT32, TUINT16}: twoOpsAndType{ssa.OpCvt32Fto32, ssa.OpTrunc32to16, TINT32},
twoTypes{TFLOAT32, TUINT32}: twoOpsAndType{ssa.OpCvt32Fto64, ssa.OpTrunc64to32, TINT64}, // go wide to dodge unsigned
twoTypes{TFLOAT32, TUINT64}: twoOpsAndType{ssa.OpInvalid, ssa.OpCopy, TUINT64}, // Cvt32Fto64U, branchy code expansion instead
twoTypes{TFLOAT64, TUINT8}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to8, TINT32},
twoTypes{TFLOAT64, TUINT16}: twoOpsAndType{ssa.OpCvt64Fto32, ssa.OpTrunc32to16, TINT32},
twoTypes{TFLOAT64, TUINT32}: twoOpsAndType{ssa.OpCvt64Fto64, ssa.OpTrunc64to32, TINT64}, // go wide to dodge unsigned
twoTypes{TFLOAT64, TUINT64}: twoOpsAndType{ssa.OpInvalid, ssa.OpCopy, TUINT64}, // Cvt64Fto64U, branchy code expansion instead
// float
twoTypes{TFLOAT64, TFLOAT32}: twoOpsAndType{ssa.OpCvt64Fto32F, ssa.OpCopy, TFLOAT32},
twoTypes{TFLOAT64, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCopy, TFLOAT64},
twoTypes{TFLOAT32, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCopy, TFLOAT32},
twoTypes{TFLOAT32, TFLOAT64}: twoOpsAndType{ssa.OpCvt32Fto64F, ssa.OpCopy, TFLOAT64},
}
// this map is used only for 32-bit arch, and only includes the difference
// on 32-bit arch, don't use int64<->float conversion for uint32
var fpConvOpToSSA32 = map[twoTypes]twoOpsAndType{
twoTypes{TUINT32, TFLOAT32}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32Uto32F, TUINT32},
twoTypes{TUINT32, TFLOAT64}: twoOpsAndType{ssa.OpCopy, ssa.OpCvt32Uto64F, TUINT32},
twoTypes{TFLOAT32, TUINT32}: twoOpsAndType{ssa.OpCvt32Fto32U, ssa.OpCopy, TUINT32},
twoTypes{TFLOAT64, TUINT32}: twoOpsAndType{ssa.OpCvt64Fto32U, ssa.OpCopy, TUINT32},
}
var shiftOpToSSA = map[opAndTwoTypes]ssa.Op{
opAndTwoTypes{OLSH, TINT8, TUINT8}: ssa.OpLsh8x8,
opAndTwoTypes{OLSH, TUINT8, TUINT8}: ssa.OpLsh8x8,
opAndTwoTypes{OLSH, TINT8, TUINT16}: ssa.OpLsh8x16,
opAndTwoTypes{OLSH, TUINT8, TUINT16}: ssa.OpLsh8x16,
opAndTwoTypes{OLSH, TINT8, TUINT32}: ssa.OpLsh8x32,
opAndTwoTypes{OLSH, TUINT8, TUINT32}: ssa.OpLsh8x32,
opAndTwoTypes{OLSH, TINT8, TUINT64}: ssa.OpLsh8x64,
opAndTwoTypes{OLSH, TUINT8, TUINT64}: ssa.OpLsh8x64,
opAndTwoTypes{OLSH, TINT16, TUINT8}: ssa.OpLsh16x8,
opAndTwoTypes{OLSH, TUINT16, TUINT8}: ssa.OpLsh16x8,
opAndTwoTypes{OLSH, TINT16, TUINT16}: ssa.OpLsh16x16,
opAndTwoTypes{OLSH, TUINT16, TUINT16}: ssa.OpLsh16x16,
opAndTwoTypes{OLSH, TINT16, TUINT32}: ssa.OpLsh16x32,
opAndTwoTypes{OLSH, TUINT16, TUINT32}: ssa.OpLsh16x32,
opAndTwoTypes{OLSH, TINT16, TUINT64}: ssa.OpLsh16x64,
opAndTwoTypes{OLSH, TUINT16, TUINT64}: ssa.OpLsh16x64,
opAndTwoTypes{OLSH, TINT32, TUINT8}: ssa.OpLsh32x8,
opAndTwoTypes{OLSH, TUINT32, TUINT8}: ssa.OpLsh32x8,
opAndTwoTypes{OLSH, TINT32, TUINT16}: ssa.OpLsh32x16,
opAndTwoTypes{OLSH, TUINT32, TUINT16}: ssa.OpLsh32x16,
opAndTwoTypes{OLSH, TINT32, TUINT32}: ssa.OpLsh32x32,
opAndTwoTypes{OLSH, TUINT32, TUINT32}: ssa.OpLsh32x32,
opAndTwoTypes{OLSH, TINT32, TUINT64}: ssa.OpLsh32x64,
opAndTwoTypes{OLSH, TUINT32, TUINT64}: ssa.OpLsh32x64,
opAndTwoTypes{OLSH, TINT64, TUINT8}: ssa.OpLsh64x8,
opAndTwoTypes{OLSH, TUINT64, TUINT8}: ssa.OpLsh64x8,
opAndTwoTypes{OLSH, TINT64, TUINT16}: ssa.OpLsh64x16,
opAndTwoTypes{OLSH, TUINT64, TUINT16}: ssa.OpLsh64x16,
opAndTwoTypes{OLSH, TINT64, TUINT32}: ssa.OpLsh64x32,
opAndTwoTypes{OLSH, TUINT64, TUINT32}: ssa.OpLsh64x32,
opAndTwoTypes{OLSH, TINT64, TUINT64}: ssa.OpLsh64x64,
opAndTwoTypes{OLSH, TUINT64, TUINT64}: ssa.OpLsh64x64,
opAndTwoTypes{ORSH, TINT8, TUINT8}: ssa.OpRsh8x8,
opAndTwoTypes{ORSH, TUINT8, TUINT8}: ssa.OpRsh8Ux8,
opAndTwoTypes{ORSH, TINT8, TUINT16}: ssa.OpRsh8x16,
opAndTwoTypes{ORSH, TUINT8, TUINT16}: ssa.OpRsh8Ux16,
opAndTwoTypes{ORSH, TINT8, TUINT32}: ssa.OpRsh8x32,
opAndTwoTypes{ORSH, TUINT8, TUINT32}: ssa.OpRsh8Ux32,
opAndTwoTypes{ORSH, TINT8, TUINT64}: ssa.OpRsh8x64,
opAndTwoTypes{ORSH, TUINT8, TUINT64}: ssa.OpRsh8Ux64,
opAndTwoTypes{ORSH, TINT16, TUINT8}: ssa.OpRsh16x8,
opAndTwoTypes{ORSH, TUINT16, TUINT8}: ssa.OpRsh16Ux8,
opAndTwoTypes{ORSH, TINT16, TUINT16}: ssa.OpRsh16x16,
opAndTwoTypes{ORSH, TUINT16, TUINT16}: ssa.OpRsh16Ux16,
opAndTwoTypes{ORSH, TINT16, TUINT32}: ssa.OpRsh16x32,
opAndTwoTypes{ORSH, TUINT16, TUINT32}: ssa.OpRsh16Ux32,
opAndTwoTypes{ORSH, TINT16, TUINT64}: ssa.OpRsh16x64,
opAndTwoTypes{ORSH, TUINT16, TUINT64}: ssa.OpRsh16Ux64,
opAndTwoTypes{ORSH, TINT32, TUINT8}: ssa.OpRsh32x8,
opAndTwoTypes{ORSH, TUINT32, TUINT8}: ssa.OpRsh32Ux8,
opAndTwoTypes{ORSH, TINT32, TUINT16}: ssa.OpRsh32x16,
opAndTwoTypes{ORSH, TUINT32, TUINT16}: ssa.OpRsh32Ux16,
opAndTwoTypes{ORSH, TINT32, TUINT32}: ssa.OpRsh32x32,
opAndTwoTypes{ORSH, TUINT32, TUINT32}: ssa.OpRsh32Ux32,
opAndTwoTypes{ORSH, TINT32, TUINT64}: ssa.OpRsh32x64,
opAndTwoTypes{ORSH, TUINT32, TUINT64}: ssa.OpRsh32Ux64,
opAndTwoTypes{ORSH, TINT64, TUINT8}: ssa.OpRsh64x8,
opAndTwoTypes{ORSH, TUINT64, TUINT8}: ssa.OpRsh64Ux8,
opAndTwoTypes{ORSH, TINT64, TUINT16}: ssa.OpRsh64x16,
opAndTwoTypes{ORSH, TUINT64, TUINT16}: ssa.OpRsh64Ux16,
opAndTwoTypes{ORSH, TINT64, TUINT32}: ssa.OpRsh64x32,
opAndTwoTypes{ORSH, TUINT64, TUINT32}: ssa.OpRsh64Ux32,
opAndTwoTypes{ORSH, TINT64, TUINT64}: ssa.OpRsh64x64,
opAndTwoTypes{ORSH, TUINT64, TUINT64}: ssa.OpRsh64Ux64,
}
func (s *state) ssaShiftOp(op Op, t *Type, u *Type) ssa.Op {
etype1 := s.concreteEtype(t)
etype2 := s.concreteEtype(u)
x, ok := shiftOpToSSA[opAndTwoTypes{op, etype1, etype2}]
if !ok {
s.Unimplementedf("unhandled shift op %s etype=%s/%s", op, etype1, etype2)
}
return x
}
func (s *state) ssaRotateOp(op Op, t *Type) ssa.Op {
etype1 := s.concreteEtype(t)
x, ok := opToSSA[opAndType{op, etype1}]
if !ok {
s.Unimplementedf("unhandled rotate op %s etype=%s", op, etype1)
}
return x
}
// expr converts the expression n to ssa, adds it to s and returns the ssa result.
func (s *state) expr(n *Node) *ssa.Value {
if !(n.Op == ONAME || n.Op == OLITERAL && n.Sym != nil) {
// ONAMEs and named OLITERALs have the line number
// of the decl, not the use. See issue 14742.
s.pushLine(n.Lineno)
defer s.popLine()
}
s.stmtList(n.Ninit)
switch n.Op {
case OCFUNC:
aux := s.lookupSymbol(n, &ssa.ExternSymbol{Typ: n.Type, Sym: n.Left.Sym})
return s.entryNewValue1A(ssa.OpAddr, n.Type, aux, s.sb)
case ONAME:
if n.Class == PFUNC {
// "value" of a function is the address of the function's closure
sym := funcsym(n.Sym)
aux := &ssa.ExternSymbol{Typ: n.Type, Sym: sym}
return s.entryNewValue1A(ssa.OpAddr, Ptrto(n.Type), aux, s.sb)
}
if s.canSSA(n) {
return s.variable(n, n.Type)
}
addr, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Type, addr, s.mem())
case OCLOSUREVAR:
addr, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Type, addr, s.mem())
case OLITERAL:
switch u := n.Val().U.(type) {
case *Mpint:
i := u.Int64()
switch n.Type.Size() {
case 1:
return s.constInt8(n.Type, int8(i))
case 2:
return s.constInt16(n.Type, int16(i))
case 4:
return s.constInt32(n.Type, int32(i))
case 8:
return s.constInt64(n.Type, i)
default:
s.Fatalf("bad integer size %d", n.Type.Size())
return nil
}
case string:
if u == "" {
return s.constEmptyString(n.Type)
}
return s.entryNewValue0A(ssa.OpConstString, n.Type, u)
case bool:
return s.constBool(u)
case *NilVal:
t := n.Type
switch {
case t.IsSlice():
return s.constSlice(t)
case t.IsInterface():
return s.constInterface(t)
default:
return s.constNil(t)
}
case *Mpflt:
switch n.Type.Size() {
case 4:
return s.constFloat32(n.Type, u.Float32())
case 8:
return s.constFloat64(n.Type, u.Float64())
default:
s.Fatalf("bad float size %d", n.Type.Size())
return nil
}
case *Mpcplx:
r := &u.Real
i := &u.Imag
switch n.Type.Size() {
case 8:
pt := Types[TFLOAT32]
return s.newValue2(ssa.OpComplexMake, n.Type,
s.constFloat32(pt, r.Float32()),
s.constFloat32(pt, i.Float32()))
case 16:
pt := Types[TFLOAT64]
return s.newValue2(ssa.OpComplexMake, n.Type,
s.constFloat64(pt, r.Float64()),
s.constFloat64(pt, i.Float64()))
default:
s.Fatalf("bad float size %d", n.Type.Size())
return nil
}
default:
s.Unimplementedf("unhandled OLITERAL %v", n.Val().Ctype())
return nil
}
case OCONVNOP:
to := n.Type
from := n.Left.Type
// Assume everything will work out, so set up our return value.
// Anything interesting that happens from here is a fatal.
x := s.expr(n.Left)
// Special case for not confusing GC and liveness.
// We don't want pointers accidentally classified
// as not-pointers or vice-versa because of copy
// elision.
if to.IsPtrShaped() != from.IsPtrShaped() {
return s.newValue2(ssa.OpConvert, to, x, s.mem())
}
v := s.newValue1(ssa.OpCopy, to, x) // ensure that v has the right type
// CONVNOP closure
if to.Etype == TFUNC && from.IsPtrShaped() {
return v
}
// named <--> unnamed type or typed <--> untyped const
if from.Etype == to.Etype {
return v
}
// unsafe.Pointer <--> *T
if to.Etype == TUNSAFEPTR && from.IsPtr() || from.Etype == TUNSAFEPTR && to.IsPtr() {
return v
}
dowidth(from)
dowidth(to)
if from.Width != to.Width {
s.Fatalf("CONVNOP width mismatch %v (%d) -> %v (%d)\n", from, from.Width, to, to.Width)
return nil
}
if etypesign(from.Etype) != etypesign(to.Etype) {
s.Fatalf("CONVNOP sign mismatch %v (%s) -> %v (%s)\n", from, from.Etype, to, to.Etype)
return nil
}
if instrumenting {
// These appear to be fine, but they fail the
// integer constraint below, so okay them here.
// Sample non-integer conversion: map[string]string -> *uint8
return v
}
if etypesign(from.Etype) == 0 {
s.Fatalf("CONVNOP unrecognized non-integer %v -> %v\n", from, to)
return nil
}
// integer, same width, same sign
return v
case OCONV:
x := s.expr(n.Left)
ft := n.Left.Type // from type
tt := n.Type // to type
if ft.IsInteger() && tt.IsInteger() {
var op ssa.Op
if tt.Size() == ft.Size() {
op = ssa.OpCopy
} else if tt.Size() < ft.Size() {
// truncation
switch 10*ft.Size() + tt.Size() {
case 21:
op = ssa.OpTrunc16to8
case 41:
op = ssa.OpTrunc32to8
case 42:
op = ssa.OpTrunc32to16
case 81:
op = ssa.OpTrunc64to8
case 82:
op = ssa.OpTrunc64to16
case 84:
op = ssa.OpTrunc64to32
default:
s.Fatalf("weird integer truncation %s -> %s", ft, tt)
}
} else if ft.IsSigned() {
// sign extension
switch 10*ft.Size() + tt.Size() {
case 12:
op = ssa.OpSignExt8to16
case 14:
op = ssa.OpSignExt8to32
case 18:
op = ssa.OpSignExt8to64
case 24:
op = ssa.OpSignExt16to32
case 28:
op = ssa.OpSignExt16to64
case 48:
op = ssa.OpSignExt32to64
default:
s.Fatalf("bad integer sign extension %s -> %s", ft, tt)
}
} else {
// zero extension
switch 10*ft.Size() + tt.Size() {
case 12:
op = ssa.OpZeroExt8to16
case 14:
op = ssa.OpZeroExt8to32
case 18:
op = ssa.OpZeroExt8to64
case 24:
op = ssa.OpZeroExt16to32
case 28:
op = ssa.OpZeroExt16to64
case 48:
op = ssa.OpZeroExt32to64
default:
s.Fatalf("weird integer sign extension %s -> %s", ft, tt)
}
}
return s.newValue1(op, n.Type, x)
}
if ft.IsFloat() || tt.IsFloat() {
conv, ok := fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]
if s.config.IntSize == 4 && Thearch.LinkArch.Name != "amd64p32" {
if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
conv = conv1
}
}
if !ok {
s.Fatalf("weird float conversion %s -> %s", ft, tt)
}
op1, op2, it := conv.op1, conv.op2, conv.intermediateType
if op1 != ssa.OpInvalid && op2 != ssa.OpInvalid {
// normal case, not tripping over unsigned 64
if op1 == ssa.OpCopy {
if op2 == ssa.OpCopy {
return x
}
return s.newValue1(op2, n.Type, x)
}
if op2 == ssa.OpCopy {
return s.newValue1(op1, n.Type, x)
}
return s.newValue1(op2, n.Type, s.newValue1(op1, Types[it], x))
}
// Tricky 64-bit unsigned cases.
if ft.IsInteger() {
// therefore tt is float32 or float64, and ft is also unsigned
if tt.Size() == 4 {
return s.uint64Tofloat32(n, x, ft, tt)
}
if tt.Size() == 8 {
return s.uint64Tofloat64(n, x, ft, tt)
}
s.Fatalf("weird unsigned integer to float conversion %s -> %s", ft, tt)
}
// therefore ft is float32 or float64, and tt is unsigned integer
if ft.Size() == 4 {
return s.float32ToUint64(n, x, ft, tt)
}
if ft.Size() == 8 {
return s.float64ToUint64(n, x, ft, tt)
}
s.Fatalf("weird float to unsigned integer conversion %s -> %s", ft, tt)
return nil
}
if ft.IsComplex() && tt.IsComplex() {
var op ssa.Op
if ft.Size() == tt.Size() {
op = ssa.OpCopy
} else if ft.Size() == 8 && tt.Size() == 16 {
op = ssa.OpCvt32Fto64F
} else if ft.Size() == 16 && tt.Size() == 8 {
op = ssa.OpCvt64Fto32F
} else {
s.Fatalf("weird complex conversion %s -> %s", ft, tt)
}
ftp := floatForComplex(ft)
ttp := floatForComplex(tt)
return s.newValue2(ssa.OpComplexMake, tt,
s.newValue1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, x)),
s.newValue1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, x)))
}
s.Unimplementedf("unhandled OCONV %s -> %s", n.Left.Type.Etype, n.Type.Etype)
return nil
case ODOTTYPE:
res, _ := s.dottype(n, false)
return res
// binary ops
case OLT, OEQ, ONE, OLE, OGE, OGT:
a := s.expr(n.Left)
b := s.expr(n.Right)
if n.Left.Type.IsComplex() {
pt := floatForComplex(n.Left.Type)
op := s.ssaOp(OEQ, pt)
r := s.newValue2(op, Types[TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
i := s.newValue2(op, Types[TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
c := s.newValue2(ssa.OpAnd8, Types[TBOOL], r, i)
switch n.Op {
case OEQ:
return c
case ONE:
return s.newValue1(ssa.OpNot, Types[TBOOL], c)
default:
s.Fatalf("ordered complex compare %s", n.Op)
}
}
return s.newValue2(s.ssaOp(n.Op, n.Left.Type), Types[TBOOL], a, b)
case OMUL:
a := s.expr(n.Left)
b := s.expr(n.Right)
if n.Type.IsComplex() {
mulop := ssa.OpMul64F
addop := ssa.OpAdd64F
subop := ssa.OpSub64F
pt := floatForComplex(n.Type) // Could be Float32 or Float64
wt := Types[TFLOAT64] // Compute in Float64 to minimize cancelation error
areal := s.newValue1(ssa.OpComplexReal, pt, a)
breal := s.newValue1(ssa.OpComplexReal, pt, b)
aimag := s.newValue1(ssa.OpComplexImag, pt, a)
bimag := s.newValue1(ssa.OpComplexImag, pt, b)
if pt != wt { // Widen for calculation
areal = s.newValue1(ssa.OpCvt32Fto64F, wt, areal)
breal = s.newValue1(ssa.OpCvt32Fto64F, wt, breal)
aimag = s.newValue1(ssa.OpCvt32Fto64F, wt, aimag)
bimag = s.newValue1(ssa.OpCvt32Fto64F, wt, bimag)
}
xreal := s.newValue2(subop, wt, s.newValue2(mulop, wt, areal, breal), s.newValue2(mulop, wt, aimag, bimag))
ximag := s.newValue2(addop, wt, s.newValue2(mulop, wt, areal, bimag), s.newValue2(mulop, wt, aimag, breal))
if pt != wt { // Narrow to store back
xreal = s.newValue1(ssa.OpCvt64Fto32F, pt, xreal)
ximag = s.newValue1(ssa.OpCvt64Fto32F, pt, ximag)
}
return s.newValue2(ssa.OpComplexMake, n.Type, xreal, ximag)
}
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case ODIV:
a := s.expr(n.Left)
b := s.expr(n.Right)
if n.Type.IsComplex() {
// TODO this is not executed because the front-end substitutes a runtime call.
// That probably ought to change; with modest optimization the widen/narrow
// conversions could all be elided in larger expression trees.
mulop := ssa.OpMul64F
addop := ssa.OpAdd64F
subop := ssa.OpSub64F
divop := ssa.OpDiv64F
pt := floatForComplex(n.Type) // Could be Float32 or Float64
wt := Types[TFLOAT64] // Compute in Float64 to minimize cancelation error
areal := s.newValue1(ssa.OpComplexReal, pt, a)
breal := s.newValue1(ssa.OpComplexReal, pt, b)
aimag := s.newValue1(ssa.OpComplexImag, pt, a)
bimag := s.newValue1(ssa.OpComplexImag, pt, b)
if pt != wt { // Widen for calculation
areal = s.newValue1(ssa.OpCvt32Fto64F, wt, areal)
breal = s.newValue1(ssa.OpCvt32Fto64F, wt, breal)
aimag = s.newValue1(ssa.OpCvt32Fto64F, wt, aimag)
bimag = s.newValue1(ssa.OpCvt32Fto64F, wt, bimag)
}
denom := s.newValue2(addop, wt, s.newValue2(mulop, wt, breal, breal), s.newValue2(mulop, wt, bimag, bimag))
xreal := s.newValue2(addop, wt, s.newValue2(mulop, wt, areal, breal), s.newValue2(mulop, wt, aimag, bimag))
ximag := s.newValue2(subop, wt, s.newValue2(mulop, wt, aimag, breal), s.newValue2(mulop, wt, areal, bimag))
// TODO not sure if this is best done in wide precision or narrow
// Double-rounding might be an issue.
// Note that the pre-SSA implementation does the entire calculation
// in wide format, so wide is compatible.
xreal = s.newValue2(divop, wt, xreal, denom)
ximag = s.newValue2(divop, wt, ximag, denom)
if pt != wt { // Narrow to store back
xreal = s.newValue1(ssa.OpCvt64Fto32F, pt, xreal)
ximag = s.newValue1(ssa.OpCvt64Fto32F, pt, ximag)
}
return s.newValue2(ssa.OpComplexMake, n.Type, xreal, ximag)
}
if n.Type.IsFloat() {
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
} else {
// do a size-appropriate check for zero
cmp := s.newValue2(s.ssaOp(ONE, n.Type), Types[TBOOL], b, s.zeroVal(n.Type))
s.check(cmp, panicdivide)
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
}
case OMOD:
a := s.expr(n.Left)
b := s.expr(n.Right)
// do a size-appropriate check for zero
cmp := s.newValue2(s.ssaOp(ONE, n.Type), Types[TBOOL], b, s.zeroVal(n.Type))
s.check(cmp, panicdivide)
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case OADD, OSUB:
a := s.expr(n.Left)
b := s.expr(n.Right)
if n.Type.IsComplex() {
pt := floatForComplex(n.Type)
op := s.ssaOp(n.Op, pt)
return s.newValue2(ssa.OpComplexMake, n.Type,
s.newValue2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
s.newValue2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
}
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case OAND, OOR, OHMUL, OXOR:
a := s.expr(n.Left)
b := s.expr(n.Right)
return s.newValue2(s.ssaOp(n.Op, n.Type), a.Type, a, b)
case OLSH, ORSH:
a := s.expr(n.Left)
b := s.expr(n.Right)
return s.newValue2(s.ssaShiftOp(n.Op, n.Type, n.Right.Type), a.Type, a, b)
case OLROT:
a := s.expr(n.Left)
i := n.Right.Int64()
if i <= 0 || i >= n.Type.Size()*8 {
s.Fatalf("Wrong rotate distance for LROT, expected 1 through %d, saw %d", n.Type.Size()*8-1, i)
}
return s.newValue1I(s.ssaRotateOp(n.Op, n.Type), a.Type, i, a)
case OANDAND, OOROR:
// To implement OANDAND (and OOROR), we introduce a
// new temporary variable to hold the result. The
// variable is associated with the OANDAND node in the
// s.vars table (normally variables are only
// associated with ONAME nodes). We convert
// A && B
// to
// var = A
// if var {
// var = B
// }
// Using var in the subsequent block introduces the
// necessary phi variable.
el := s.expr(n.Left)
s.vars[n] = el
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(el)
// In theory, we should set b.Likely here based on context.
// However, gc only gives us likeliness hints
// in a single place, for plain OIF statements,
// and passing around context is finnicky, so don't bother for now.
bRight := s.f.NewBlock(ssa.BlockPlain)
bResult := s.f.NewBlock(ssa.BlockPlain)
if n.Op == OANDAND {
b.AddEdgeTo(bRight)
b.AddEdgeTo(bResult)
} else if n.Op == OOROR {
b.AddEdgeTo(bResult)
b.AddEdgeTo(bRight)
}
s.startBlock(bRight)
er := s.expr(n.Right)
s.vars[n] = er
b = s.endBlock()
b.AddEdgeTo(bResult)
s.startBlock(bResult)
return s.variable(n, Types[TBOOL])
case OCOMPLEX:
r := s.expr(n.Left)
i := s.expr(n.Right)
return s.newValue2(ssa.OpComplexMake, n.Type, r, i)
// unary ops
case OMINUS:
a := s.expr(n.Left)
if n.Type.IsComplex() {
tp := floatForComplex(n.Type)
negop := s.ssaOp(n.Op, tp)
return s.newValue2(ssa.OpComplexMake, n.Type,
s.newValue1(negop, tp, s.newValue1(ssa.OpComplexReal, tp, a)),
s.newValue1(negop, tp, s.newValue1(ssa.OpComplexImag, tp, a)))
}
return s.newValue1(s.ssaOp(n.Op, n.Type), a.Type, a)
case ONOT, OCOM, OSQRT:
a := s.expr(n.Left)
return s.newValue1(s.ssaOp(n.Op, n.Type), a.Type, a)
case OIMAG, OREAL:
a := s.expr(n.Left)
return s.newValue1(s.ssaOp(n.Op, n.Left.Type), n.Type, a)
case OPLUS:
return s.expr(n.Left)
case OADDR:
a, _ := s.addr(n.Left, n.Bounded)
// Note we know the volatile result is false because you can't write &f() in Go.
return a
case OINDREG:
if int(n.Reg) != Thearch.REGSP {
s.Unimplementedf("OINDREG of non-SP register %s in expr: %v", obj.Rconv(int(n.Reg)), n)
return nil
}
addr := s.entryNewValue1I(ssa.OpOffPtr, Ptrto(n.Type), n.Xoffset, s.sp)
return s.newValue2(ssa.OpLoad, n.Type, addr, s.mem())
case OIND:
p := s.exprPtr(n.Left, false, n.Lineno)
return s.newValue2(ssa.OpLoad, n.Type, p, s.mem())
case ODOT:
t := n.Left.Type
if canSSAType(t) {
v := s.expr(n.Left)
return s.newValue1I(ssa.OpStructSelect, n.Type, int64(fieldIdx(n)), v)
}
p, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Type, p, s.mem())
case ODOTPTR:
p := s.exprPtr(n.Left, false, n.Lineno)
p = s.newValue1I(ssa.OpOffPtr, p.Type, n.Xoffset, p)
return s.newValue2(ssa.OpLoad, n.Type, p, s.mem())
case OINDEX:
switch {
case n.Left.Type.IsString():
a := s.expr(n.Left)
i := s.expr(n.Right)
i = s.extendIndex(i, Panicindex)
if !n.Bounded {
len := s.newValue1(ssa.OpStringLen, Types[TINT], a)
s.boundsCheck(i, len)
}
ptrtyp := Ptrto(Types[TUINT8])
ptr := s.newValue1(ssa.OpStringPtr, ptrtyp, a)
if Isconst(n.Right, CTINT) {
ptr = s.newValue1I(ssa.OpOffPtr, ptrtyp, n.Right.Int64(), ptr)
} else {
ptr = s.newValue2(ssa.OpAddPtr, ptrtyp, ptr, i)
}
return s.newValue2(ssa.OpLoad, Types[TUINT8], ptr, s.mem())
case n.Left.Type.IsSlice():
p, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Left.Type.Elem(), p, s.mem())
case n.Left.Type.IsArray():
// TODO: fix when we can SSA arrays of length 1.
p, _ := s.addr(n, false)
return s.newValue2(ssa.OpLoad, n.Left.Type.Elem(), p, s.mem())
default:
s.Fatalf("bad type for index %v", n.Left.Type)
return nil
}
case OLEN, OCAP:
switch {
case n.Left.Type.IsSlice():
op := ssa.OpSliceLen
if n.Op == OCAP {
op = ssa.OpSliceCap
}
return s.newValue1(op, Types[TINT], s.expr(n.Left))
case n.Left.Type.IsString(): // string; not reachable for OCAP
return s.newValue1(ssa.OpStringLen, Types[TINT], s.expr(n.Left))
case n.Left.Type.IsMap(), n.Left.Type.IsChan():
return s.referenceTypeBuiltin(n, s.expr(n.Left))
default: // array
return s.constInt(Types[TINT], n.Left.Type.NumElem())
}
case OSPTR:
a := s.expr(n.Left)
if n.Left.Type.IsSlice() {
return s.newValue1(ssa.OpSlicePtr, n.Type, a)
} else {
return s.newValue1(ssa.OpStringPtr, n.Type, a)
}
case OITAB:
a := s.expr(n.Left)
return s.newValue1(ssa.OpITab, n.Type, a)
case OEFACE:
tab := s.expr(n.Left)
data := s.expr(n.Right)
// The frontend allows putting things like struct{*byte} in
// the data portion of an eface. But we don't want struct{*byte}
// as a register type because (among other reasons) the liveness
// analysis is confused by the "fat" variables that result from
// such types being spilled.
// So here we ensure that we are selecting the underlying pointer
// when we build an eface.
// TODO: get rid of this now that structs can be SSA'd?
for !data.Type.IsPtrShaped() {
switch {
case data.Type.IsArray():
data = s.newValue1I(ssa.OpArrayIndex, data.Type.ElemType(), 0, data)
case data.Type.IsStruct():
for i := data.Type.NumFields() - 1; i >= 0; i-- {
f := data.Type.FieldType(i)
if f.Size() == 0 {
// eface type could also be struct{p *byte; q [0]int}
continue
}
data = s.newValue1I(ssa.OpStructSelect, f, int64(i), data)
break
}
default:
s.Fatalf("type being put into an eface isn't a pointer")
}
}
return s.newValue2(ssa.OpIMake, n.Type, tab, data)
case OSLICE, OSLICEARR, OSLICE3, OSLICE3ARR:
v := s.expr(n.Left)
var i, j, k *ssa.Value
low, high, max := n.SliceBounds()
if low != nil {
i = s.extendIndex(s.expr(low), panicslice)
}
if high != nil {
j = s.extendIndex(s.expr(high), panicslice)
}
if max != nil {
k = s.extendIndex(s.expr(max), panicslice)
}
p, l, c := s.slice(n.Left.Type, v, i, j, k)
return s.newValue3(ssa.OpSliceMake, n.Type, p, l, c)
case OSLICESTR:
v := s.expr(n.Left)
var i, j *ssa.Value
low, high, _ := n.SliceBounds()
if low != nil {
i = s.extendIndex(s.expr(low), panicslice)
}
if high != nil {
j = s.extendIndex(s.expr(high), panicslice)
}
p, l, _ := s.slice(n.Left.Type, v, i, j, nil)
return s.newValue2(ssa.OpStringMake, n.Type, p, l)
case OCALLFUNC:
if isIntrinsicCall1(n) {
return s.intrinsicCall1(n)
}
fallthrough
case OCALLINTER, OCALLMETH:
a := s.call(n, callNormal)
return s.newValue2(ssa.OpLoad, n.Type, a, s.mem())
case OGETG:
return s.newValue1(ssa.OpGetG, n.Type, s.mem())
case OAPPEND:
return s.append(n, false)
default:
s.Unimplementedf("unhandled expr %s", n.Op)
return nil
}
}
// append converts an OAPPEND node to SSA.
// If inplace is false, it converts the OAPPEND expression n to an ssa.Value,
// adds it to s, and returns the Value.
// If inplace is true, it writes the result of the OAPPEND expression n
// back to the slice being appended to, and returns nil.
// inplace MUST be set to false if the slice can be SSA'd.
func (s *state) append(n *Node, inplace bool) *ssa.Value {
// If inplace is false, process as expression "append(s, e1, e2, e3)":
//
// ptr, len, cap := s
// newlen := len + 3
// if newlen > cap {
// ptr, len, cap = growslice(s, newlen)
// newlen = len + 3 // recalculate to avoid a spill
// }
// // with write barriers, if needed:
// *(ptr+len) = e1
// *(ptr+len+1) = e2
// *(ptr+len+2) = e3
// return makeslice(ptr, newlen, cap)
//
//
// If inplace is true, process as statement "s = append(s, e1, e2, e3)":
//
// a := &s
// ptr, len, cap := s
// newlen := len + 3
// if newlen > cap {
// newptr, len, newcap = growslice(ptr, len, cap, newlen)
// vardef(a) // if necessary, advise liveness we are writing a new a
// *a.cap = newcap // write before ptr to avoid a spill
// *a.ptr = newptr // with write barrier
// }
// newlen = len + 3 // recalculate to avoid a spill
// *a.len = newlen
// // with write barriers, if needed:
// *(ptr+len) = e1
// *(ptr+len+1) = e2
// *(ptr+len+2) = e3
et := n.Type.Elem()
pt := Ptrto(et)
// Evaluate slice
sn := n.List.First() // the slice node is the first in the list
var slice, addr *ssa.Value
if inplace {
addr, _ = s.addr(sn, false)
slice = s.newValue2(ssa.OpLoad, n.Type, addr, s.mem())
} else {
slice = s.expr(sn)
}
// Allocate new blocks
grow := s.f.NewBlock(ssa.BlockPlain)
assign := s.f.NewBlock(ssa.BlockPlain)
// Decide if we need to grow
nargs := int64(n.List.Len() - 1)
p := s.newValue1(ssa.OpSlicePtr, pt, slice)
l := s.newValue1(ssa.OpSliceLen, Types[TINT], slice)
c := s.newValue1(ssa.OpSliceCap, Types[TINT], slice)
nl := s.newValue2(s.ssaOp(OADD, Types[TINT]), Types[TINT], l, s.constInt(Types[TINT], nargs))
cmp := s.newValue2(s.ssaOp(OGT, Types[TINT]), Types[TBOOL], nl, c)
s.vars[&ptrVar] = p
if !inplace {
s.vars[&newlenVar] = nl
s.vars[&capVar] = c
} else {
s.vars[&lenVar] = l
}
b := s.endBlock()
b.Kind = ssa.BlockIf
b.Likely = ssa.BranchUnlikely
b.SetControl(cmp)
b.AddEdgeTo(grow)
b.AddEdgeTo(assign)
// Call growslice
s.startBlock(grow)
taddr := s.newValue1A(ssa.OpAddr, Types[TUINTPTR], &ssa.ExternSymbol{Typ: Types[TUINTPTR], Sym: typenamesym(n.Type.Elem())}, s.sb)
r := s.rtcall(growslice, true, []*Type{pt, Types[TINT], Types[TINT]}, taddr, p, l, c, nl)
if inplace {
if sn.Op == ONAME {
// Tell liveness we're about to build a new slice
s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, sn, s.mem())
}
capaddr := s.newValue1I(ssa.OpOffPtr, pt, int64(Array_cap), addr)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, capaddr, r[2], s.mem())
s.insertWBstore(pt, addr, r[0], n.Lineno, 0)
// load the value we just stored to avoid having to spill it
s.vars[&ptrVar] = s.newValue2(ssa.OpLoad, pt, addr, s.mem())
s.vars[&lenVar] = r[1] // avoid a spill in the fast path
} else {
s.vars[&ptrVar] = r[0]
s.vars[&newlenVar] = s.newValue2(s.ssaOp(OADD, Types[TINT]), Types[TINT], r[1], s.constInt(Types[TINT], nargs))
s.vars[&capVar] = r[2]
}
b = s.endBlock()
b.AddEdgeTo(assign)
// assign new elements to slots
s.startBlock(assign)
if inplace {
l = s.variable(&lenVar, Types[TINT]) // generates phi for len
nl = s.newValue2(s.ssaOp(OADD, Types[TINT]), Types[TINT], l, s.constInt(Types[TINT], nargs))
lenaddr := s.newValue1I(ssa.OpOffPtr, pt, int64(Array_nel), addr)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, lenaddr, nl, s.mem())
}
// Evaluate args
type argRec struct {
// if store is true, we're appending the value v. If false, we're appending the
// value at *v. If store==false, isVolatile reports whether the source
// is in the outargs section of the stack frame.
v *ssa.Value
store bool
isVolatile bool
}
args := make([]argRec, 0, nargs)
for _, n := range n.List.Slice()[1:] {
if canSSAType(n.Type) {
args = append(args, argRec{v: s.expr(n), store: true})
} else {
v, isVolatile := s.addr(n, false)
args = append(args, argRec{v: v, isVolatile: isVolatile})
}
}
p = s.variable(&ptrVar, pt) // generates phi for ptr
if !inplace {
nl = s.variable(&newlenVar, Types[TINT]) // generates phi for nl
c = s.variable(&capVar, Types[TINT]) // generates phi for cap
}
p2 := s.newValue2(ssa.OpPtrIndex, pt, p, l)
// TODO: just one write barrier call for all of these writes?
// TODO: maybe just one writeBarrier.enabled check?
for i, arg := range args {
addr := s.newValue2(ssa.OpPtrIndex, pt, p2, s.constInt(Types[TINT], int64(i)))
if arg.store {
if haspointers(et) {
s.insertWBstore(et, addr, arg.v, n.Lineno, 0)
} else {
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, et.Size(), addr, arg.v, s.mem())
}
} else {
if haspointers(et) {
s.insertWBmove(et, addr, arg.v, n.Lineno, arg.isVolatile)
} else {
s.vars[&memVar] = s.newValue3I(ssa.OpMove, ssa.TypeMem, SizeAlignAuxInt(et), addr, arg.v, s.mem())
}
}
}
delete(s.vars, &ptrVar)
if inplace {
delete(s.vars, &lenVar)
return nil
}
delete(s.vars, &newlenVar)
delete(s.vars, &capVar)
// make result
return s.newValue3(ssa.OpSliceMake, n.Type, p, nl, c)
}
// condBranch evaluates the boolean expression cond and branches to yes
// if cond is true and no if cond is false.
// This function is intended to handle && and || better than just calling
// s.expr(cond) and branching on the result.
func (s *state) condBranch(cond *Node, yes, no *ssa.Block, likely int8) {
if cond.Op == OANDAND {
mid := s.f.NewBlock(ssa.BlockPlain)
s.stmtList(cond.Ninit)
s.condBranch(cond.Left, mid, no, max8(likely, 0))
s.startBlock(mid)
s.condBranch(cond.Right, yes, no, likely)
return
// Note: if likely==1, then both recursive calls pass 1.
// If likely==-1, then we don't have enough information to decide
// whether the first branch is likely or not. So we pass 0 for
// the likeliness of the first branch.
// TODO: have the frontend give us branch prediction hints for
// OANDAND and OOROR nodes (if it ever has such info).
}
if cond.Op == OOROR {
mid := s.f.NewBlock(ssa.BlockPlain)
s.stmtList(cond.Ninit)
s.condBranch(cond.Left, yes, mid, min8(likely, 0))
s.startBlock(mid)
s.condBranch(cond.Right, yes, no, likely)
return
// Note: if likely==-1, then both recursive calls pass -1.
// If likely==1, then we don't have enough info to decide
// the likelihood of the first branch.
}
if cond.Op == ONOT {
s.stmtList(cond.Ninit)
s.condBranch(cond.Left, no, yes, -likely)
return
}
c := s.expr(cond)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(c)
b.Likely = ssa.BranchPrediction(likely) // gc and ssa both use -1/0/+1 for likeliness
b.AddEdgeTo(yes)
b.AddEdgeTo(no)
}
type skipMask uint8
const (
skipPtr skipMask = 1 << iota
skipLen
skipCap
)
// assign does left = right.
// Right has already been evaluated to ssa, left has not.
// If deref is true, then we do left = *right instead (and right has already been nil-checked).
// If deref is true and right == nil, just do left = 0.
// If deref is true, rightIsVolatile reports whether right points to volatile (clobbered by a call) storage.
// Include a write barrier if wb is true.
// skip indicates assignments (at the top level) that can be avoided.
func (s *state) assign(left *Node, right *ssa.Value, wb, deref bool, line int32, skip skipMask, rightIsVolatile bool) {
if left.Op == ONAME && isblank(left) {
return
}
t := left.Type
dowidth(t)
if s.canSSA(left) {
if deref {
s.Fatalf("can SSA LHS %s but not RHS %s", left, right)
}
if left.Op == ODOT {
// We're assigning to a field of an ssa-able value.
// We need to build a new structure with the new value for the
// field we're assigning and the old values for the other fields.
// For instance:
// type T struct {a, b, c int}
// var T x
// x.b = 5
// For the x.b = 5 assignment we want to generate x = T{x.a, 5, x.c}
// Grab information about the structure type.
t := left.Left.Type
nf := t.NumFields()
idx := fieldIdx(left)
// Grab old value of structure.
old := s.expr(left.Left)
// Make new structure.
new := s.newValue0(ssa.StructMakeOp(t.NumFields()), t)
// Add fields as args.
for i := 0; i < nf; i++ {
if i == idx {
new.AddArg(right)
} else {
new.AddArg(s.newValue1I(ssa.OpStructSelect, t.FieldType(i), int64(i), old))
}
}
// Recursively assign the new value we've made to the base of the dot op.
s.assign(left.Left, new, false, false, line, 0, rightIsVolatile)
// TODO: do we need to update named values here?
return
}
// Update variable assignment.
s.vars[left] = right
s.addNamedValue(left, right)
return
}
// Left is not ssa-able. Compute its address.
addr, _ := s.addr(left, false)
if left.Op == ONAME && skip == 0 {
s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, left, s.mem())
}
if deref {
// Treat as a mem->mem move.
if right == nil {
s.vars[&memVar] = s.newValue2I(ssa.OpZero, ssa.TypeMem, SizeAlignAuxInt(t), addr, s.mem())
return
}
if wb {
s.insertWBmove(t, addr, right, line, rightIsVolatile)
return
}
s.vars[&memVar] = s.newValue3I(ssa.OpMove, ssa.TypeMem, SizeAlignAuxInt(t), addr, right, s.mem())
return
}
// Treat as a store.
if wb {
if skip&skipPtr != 0 {
// Special case: if we don't write back the pointers, don't bother
// doing the write barrier check.
s.storeTypeScalars(t, addr, right, skip)
return
}
s.insertWBstore(t, addr, right, line, skip)
return
}
if skip != 0 {
if skip&skipPtr == 0 {
s.storeTypePtrs(t, addr, right)
}
s.storeTypeScalars(t, addr, right, skip)
return
}
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, t.Size(), addr, right, s.mem())
}
// zeroVal returns the zero value for type t.
func (s *state) zeroVal(t *Type) *ssa.Value {
switch {
case t.IsInteger():
switch t.Size() {
case 1:
return s.constInt8(t, 0)
case 2:
return s.constInt16(t, 0)
case 4:
return s.constInt32(t, 0)
case 8:
return s.constInt64(t, 0)
default:
s.Fatalf("bad sized integer type %s", t)
}
case t.IsFloat():
switch t.Size() {
case 4:
return s.constFloat32(t, 0)
case 8:
return s.constFloat64(t, 0)
default:
s.Fatalf("bad sized float type %s", t)
}
case t.IsComplex():
switch t.Size() {
case 8:
z := s.constFloat32(Types[TFLOAT32], 0)
return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
case 16:
z := s.constFloat64(Types[TFLOAT64], 0)
return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
default:
s.Fatalf("bad sized complex type %s", t)
}
case t.IsString():
return s.constEmptyString(t)
case t.IsPtrShaped():
return s.constNil(t)
case t.IsBoolean():
return s.constBool(false)
case t.IsInterface():
return s.constInterface(t)
case t.IsSlice():
return s.constSlice(t)
case t.IsStruct():
n := t.NumFields()
v := s.entryNewValue0(ssa.StructMakeOp(t.NumFields()), t)
for i := 0; i < n; i++ {
v.AddArg(s.zeroVal(t.FieldType(i).(*Type)))
}
return v
}
s.Unimplementedf("zero for type %v not implemented", t)
return nil
}
type callKind int8
const (
callNormal callKind = iota
callDefer
callGo
)
// isSSAIntrinsic1 returns true if n is a call to a recognized 1-arg intrinsic
// that can be handled by the SSA backend.
// SSA uses this, but so does the front end to see if should not
// inline a function because it is a candidate for intrinsic
// substitution.
func isSSAIntrinsic1(s *Sym) bool {
// The test below is not quite accurate -- in the event that
// a function is disabled on a per-function basis, for example
// because of hash-keyed binary failure search, SSA might be
// disabled for that function but it would not be noted here,
// and thus an inlining would not occur (in practice, inlining
// so far has only been noticed for Bswap32 and the 16-bit count
// leading/trailing instructions, but heuristics might change
// in the future or on different architectures).
if !ssaEnabled || ssa.IntrinsicsDisable || Thearch.LinkArch.Family != sys.AMD64 {
return false
}
if s != nil && s.Pkg != nil && s.Pkg.Path == "runtime/internal/sys" {
switch s.Name {
case
"Ctz64", "Ctz32", "Ctz16",
"Bswap64", "Bswap32":
return true
}
}
return false
}
func isIntrinsicCall1(n *Node) bool {
if n == nil || n.Left == nil {
return false
}
return isSSAIntrinsic1(n.Left.Sym)
}
// intrinsicFirstArg extracts arg from n.List and eval
func (s *state) intrinsicFirstArg(n *Node) *ssa.Value {
x := n.List.First()
if x.Op == OAS {
x = x.Right
}
return s.expr(x)
}
// intrinsicCall1 converts a call to a recognized 1-arg intrinsic
// into the intrinsic
func (s *state) intrinsicCall1(n *Node) *ssa.Value {
var result *ssa.Value
switch n.Left.Sym.Name {
case "Ctz64":
result = s.newValue1(ssa.OpCtz64, Types[TUINT64], s.intrinsicFirstArg(n))
case "Ctz32":
result = s.newValue1(ssa.OpCtz32, Types[TUINT32], s.intrinsicFirstArg(n))
case "Ctz16":
result = s.newValue1(ssa.OpCtz16, Types[TUINT16], s.intrinsicFirstArg(n))
case "Bswap64":
result = s.newValue1(ssa.OpBswap64, Types[TUINT64], s.intrinsicFirstArg(n))
case "Bswap32":
result = s.newValue1(ssa.OpBswap32, Types[TUINT32], s.intrinsicFirstArg(n))
}
if result == nil {
Fatalf("Unknown special call: %v", n.Left.Sym)
}
if ssa.IntrinsicsDebug > 0 {
Warnl(n.Lineno, "intrinsic substitution for %v with %s", n.Left.Sym.Name, result.LongString())
}
return result
}
// Calls the function n using the specified call type.
// Returns the address of the return value (or nil if none).
func (s *state) call(n *Node, k callKind) *ssa.Value {
var sym *Sym // target symbol (if static)
var closure *ssa.Value // ptr to closure to run (if dynamic)
var codeptr *ssa.Value // ptr to target code (if dynamic)
var rcvr *ssa.Value // receiver to set
fn := n.Left
switch n.Op {
case OCALLFUNC:
if k == callNormal && fn.Op == ONAME && fn.Class == PFUNC {
sym = fn.Sym
break
}
closure = s.expr(fn)
case OCALLMETH:
if fn.Op != ODOTMETH {
Fatalf("OCALLMETH: n.Left not an ODOTMETH: %v", fn)
}
if k == callNormal {
sym = fn.Sym
break
}
n2 := newname(fn.Sym)
n2.Class = PFUNC
n2.Lineno = fn.Lineno
closure = s.expr(n2)
// Note: receiver is already assigned in n.List, so we don't
// want to set it here.
case OCALLINTER:
if fn.Op != ODOTINTER {
Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op)
}
i := s.expr(fn.Left)
itab := s.newValue1(ssa.OpITab, Types[TUINTPTR], i)
if k != callNormal {
s.nilCheck(itab)
}
itabidx := fn.Xoffset + 3*int64(Widthptr) + 8 // offset of fun field in runtime.itab
itab = s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TUINTPTR]), itabidx, itab)
if k == callNormal {
codeptr = s.newValue2(ssa.OpLoad, Types[TUINTPTR], itab, s.mem())
} else {
closure = itab
}
rcvr = s.newValue1(ssa.OpIData, Types[TUINTPTR], i)
}
dowidth(fn.Type)
stksize := fn.Type.ArgWidth() // includes receiver
// Run all argument assignments. The arg slots have already
// been offset by the appropriate amount (+2*widthptr for go/defer,
// +widthptr for interface calls).
// For OCALLMETH, the receiver is set in these statements.
s.stmtList(n.List)
// Set receiver (for interface calls)
if rcvr != nil {
argStart := Ctxt.FixedFrameSize()
if k != callNormal {
argStart += int64(2 * Widthptr)
}
addr := s.entryNewValue1I(ssa.OpOffPtr, Ptrto(Types[TUINTPTR]), argStart, s.sp)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, int64(Widthptr), addr, rcvr, s.mem())
}
// Defer/go args
if k != callNormal {
// Write argsize and closure (args to Newproc/Deferproc).
argStart := Ctxt.FixedFrameSize()
argsize := s.constInt32(Types[TUINT32], int32(stksize))
addr := s.entryNewValue1I(ssa.OpOffPtr, Ptrto(Types[TUINT32]), argStart, s.sp)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, 4, addr, argsize, s.mem())
addr = s.entryNewValue1I(ssa.OpOffPtr, Ptrto(Types[TUINTPTR]), argStart+int64(Widthptr), s.sp)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, int64(Widthptr), addr, closure, s.mem())
stksize += 2 * int64(Widthptr)
}
// call target
bNext := s.f.NewBlock(ssa.BlockPlain)
var call *ssa.Value
switch {
case k == callDefer:
call = s.newValue1(ssa.OpDeferCall, ssa.TypeMem, s.mem())
case k == callGo:
call = s.newValue1(ssa.OpGoCall, ssa.TypeMem, s.mem())
case closure != nil:
codeptr = s.newValue2(ssa.OpLoad, Types[TUINTPTR], closure, s.mem())
call = s.newValue3(ssa.OpClosureCall, ssa.TypeMem, codeptr, closure, s.mem())
case codeptr != nil:
call = s.newValue2(ssa.OpInterCall, ssa.TypeMem, codeptr, s.mem())
case sym != nil:
call = s.newValue1A(ssa.OpStaticCall, ssa.TypeMem, sym, s.mem())
default:
Fatalf("bad call type %s %v", n.Op, n)
}
call.AuxInt = stksize // Call operations carry the argsize of the callee along with them
// Finish call block
s.vars[&memVar] = call
b := s.endBlock()
b.Kind = ssa.BlockCall
b.SetControl(call)
b.AddEdgeTo(bNext)
if k == callDefer {
// Add recover edge to exit code.
b.Kind = ssa.BlockDefer
r := s.f.NewBlock(ssa.BlockPlain)
s.startBlock(r)
s.exit()
b.AddEdgeTo(r)
b.Likely = ssa.BranchLikely
}
// Start exit block, find address of result.
s.startBlock(bNext)
// Keep input pointer args live across calls. This is a bandaid until 1.8.
for _, n := range s.ptrargs {
s.vars[&memVar] = s.newValue2(ssa.OpKeepAlive, ssa.TypeMem, s.variable(n, n.Type), s.mem())
}
res := n.Left.Type.Results()
if res.NumFields() == 0 || k != callNormal {
// call has no return value. Continue with the next statement.
return nil
}
fp := res.Field(0)
return s.entryNewValue1I(ssa.OpOffPtr, Ptrto(fp.Type), fp.Offset+Ctxt.FixedFrameSize(), s.sp)
}
// etypesign returns the signed-ness of e, for integer/pointer etypes.
// -1 means signed, +1 means unsigned, 0 means non-integer/non-pointer.
func etypesign(e EType) int8 {
switch e {
case TINT8, TINT16, TINT32, TINT64, TINT:
return -1
case TUINT8, TUINT16, TUINT32, TUINT64, TUINT, TUINTPTR, TUNSAFEPTR:
return +1
}
return 0
}
// lookupSymbol is used to retrieve the symbol (Extern, Arg or Auto) used for a particular node.
// This improves the effectiveness of cse by using the same Aux values for the
// same symbols.
func (s *state) lookupSymbol(n *Node, sym interface{}) interface{} {
switch sym.(type) {
default:
s.Fatalf("sym %v is of uknown type %T", sym, sym)
case *ssa.ExternSymbol, *ssa.ArgSymbol, *ssa.AutoSymbol:
// these are the only valid types
}
if lsym, ok := s.varsyms[n]; ok {
return lsym
} else {
s.varsyms[n] = sym
return sym
}
}
// addr converts the address of the expression n to SSA, adds it to s and returns the SSA result.
// Also returns a bool reporting whether the returned value is "volatile", that is it
// points to the outargs section and thus the referent will be clobbered by any call.
// The value that the returned Value represents is guaranteed to be non-nil.
// If bounded is true then this address does not require a nil check for its operand
// even if that would otherwise be implied.
func (s *state) addr(n *Node, bounded bool) (*ssa.Value, bool) {
t := Ptrto(n.Type)
switch n.Op {
case ONAME:
switch n.Class {
case PEXTERN:
// global variable
aux := s.lookupSymbol(n, &ssa.ExternSymbol{Typ: n.Type, Sym: n.Sym})
v := s.entryNewValue1A(ssa.OpAddr, t, aux, s.sb)
// TODO: Make OpAddr use AuxInt as well as Aux.
if n.Xoffset != 0 {
v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, n.Xoffset, v)
}
return v, false
case PPARAM:
// parameter slot
v := s.decladdrs[n]
if v != nil {
return v, false
}
if n.String() == ".fp" {
// Special arg that points to the frame pointer.
// (Used by the race detector, others?)
aux := s.lookupSymbol(n, &ssa.ArgSymbol{Typ: n.Type, Node: n})
return s.entryNewValue1A(ssa.OpAddr, t, aux, s.sp), false
}
s.Fatalf("addr of undeclared ONAME %v. declared: %v", n, s.decladdrs)
return nil, false
case PAUTO:
aux := s.lookupSymbol(n, &ssa.AutoSymbol{Typ: n.Type, Node: n})
return s.newValue1A(ssa.OpAddr, t, aux, s.sp), false
case PPARAMOUT: // Same as PAUTO -- cannot generate LEA early.
// ensure that we reuse symbols for out parameters so
// that cse works on their addresses
aux := s.lookupSymbol(n, &ssa.ArgSymbol{Typ: n.Type, Node: n})
return s.newValue1A(ssa.OpAddr, t, aux, s.sp), false
default:
s.Unimplementedf("variable address class %v not implemented", classnames[n.Class])
return nil, false
}
case OINDREG:
// indirect off a register
// used for storing/loading arguments/returns to/from callees
if int(n.Reg) != Thearch.REGSP {
s.Unimplementedf("OINDREG of non-SP register %s in addr: %v", obj.Rconv(int(n.Reg)), n)
return nil, false
}
return s.entryNewValue1I(ssa.OpOffPtr, t, n.Xoffset, s.sp), true
case OINDEX:
if n.Left.Type.IsSlice() {
a := s.expr(n.Left)
i := s.expr(n.Right)
i = s.extendIndex(i, Panicindex)
len := s.newValue1(ssa.OpSliceLen, Types[TINT], a)
if !n.Bounded {
s.boundsCheck(i, len)
}
p := s.newValue1(ssa.OpSlicePtr, t, a)
return s.newValue2(ssa.OpPtrIndex, t, p, i), false
} else { // array
a, isVolatile := s.addr(n.Left, bounded)
i := s.expr(n.Right)
i = s.extendIndex(i, Panicindex)
len := s.constInt(Types[TINT], n.Left.Type.NumElem())
if !n.Bounded {
s.boundsCheck(i, len)
}
return s.newValue2(ssa.OpPtrIndex, Ptrto(n.Left.Type.Elem()), a, i), isVolatile
}
case OIND:
return s.exprPtr(n.Left, bounded, n.Lineno), false
case ODOT:
p, isVolatile := s.addr(n.Left, bounded)
return s.newValue1I(ssa.OpOffPtr, t, n.Xoffset, p), isVolatile
case ODOTPTR:
p := s.exprPtr(n.Left, bounded, n.Lineno)
return s.newValue1I(ssa.OpOffPtr, t, n.Xoffset, p), false
case OCLOSUREVAR:
return s.newValue1I(ssa.OpOffPtr, t, n.Xoffset,
s.entryNewValue0(ssa.OpGetClosurePtr, Ptrto(Types[TUINT8]))), false
case OCONVNOP:
addr, isVolatile := s.addr(n.Left, bounded)
return s.newValue1(ssa.OpCopy, t, addr), isVolatile // ensure that addr has the right type
case OCALLFUNC, OCALLINTER, OCALLMETH:
return s.call(n, callNormal), true
default:
s.Unimplementedf("unhandled addr %v", n.Op)
return nil, false
}
}
// canSSA reports whether n is SSA-able.
// n must be an ONAME (or an ODOT sequence with an ONAME base).
func (s *state) canSSA(n *Node) bool {
if Debug['N'] != 0 {
return false
}
for n.Op == ODOT {
n = n.Left
}
if n.Op != ONAME {
return false
}
if n.Addrtaken {
return false
}
if n.isParamHeapCopy() {
return false
}
if n.Class == PAUTOHEAP {
Fatalf("canSSA of PAUTOHEAP %v", n)
}
switch n.Class {
case PEXTERN:
return false
case PPARAMOUT:
if hasdefer {
// TODO: handle this case? Named return values must be
// in memory so that the deferred function can see them.
// Maybe do: if !strings.HasPrefix(n.String(), "~") { return false }
return false
}
if s.cgoUnsafeArgs {
// Cgo effectively takes the address of all result args,
// but the compiler can't see that.
return false
}
}
if n.Class == PPARAM && n.String() == ".this" {
// wrappers generated by genwrapper need to update
// the .this pointer in place.
// TODO: treat as a PPARMOUT?
return false
}
return canSSAType(n.Type)
// TODO: try to make more variables SSAable?
}
// canSSA reports whether variables of type t are SSA-able.
func canSSAType(t *Type) bool {
dowidth(t)
if t.Width > int64(4*Widthptr) {
// 4*Widthptr is an arbitrary constant. We want it
// to be at least 3*Widthptr so slices can be registerized.
// Too big and we'll introduce too much register pressure.
return false
}
switch t.Etype {
case TARRAY:
// We can't do arrays because dynamic indexing is
// not supported on SSA variables.
// TODO: maybe allow if length is <=1? All indexes
// are constant? Might be good for the arrays
// introduced by the compiler for variadic functions.
return false
case TSTRUCT:
if t.NumFields() > ssa.MaxStruct {
return false
}
for _, t1 := range t.Fields().Slice() {
if !canSSAType(t1.Type) {
return false
}
}
return true
default:
return true
}
}
// exprPtr evaluates n to a pointer and nil-checks it.
func (s *state) exprPtr(n *Node, bounded bool, lineno int32) *ssa.Value {
p := s.expr(n)
if bounded || n.NonNil {
if s.f.Config.Debug_checknil() && lineno > 1 {
s.f.Config.Warnl(lineno, "removed nil check")
}
return p
}
s.nilCheck(p)
return p
}
// nilCheck generates nil pointer checking code.
// Starts a new block on return, unless nil checks are disabled.
// Used only for automatically inserted nil checks,
// not for user code like 'x != nil'.
func (s *state) nilCheck(ptr *ssa.Value) {
if Disable_checknil != 0 {
return
}
chk := s.newValue2(ssa.OpNilCheck, ssa.TypeVoid, ptr, s.mem())
b := s.endBlock()
b.Kind = ssa.BlockCheck
b.SetControl(chk)
bNext := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bNext)
s.startBlock(bNext)
}
// boundsCheck generates bounds checking code. Checks if 0 <= idx < len, branches to exit if not.
// Starts a new block on return.
// idx is already converted to full int width.
func (s *state) boundsCheck(idx, len *ssa.Value) {
if Debug['B'] != 0 {
return
}
// bounds check
cmp := s.newValue2(ssa.OpIsInBounds, Types[TBOOL], idx, len)
s.check(cmp, Panicindex)
}
// sliceBoundsCheck generates slice bounds checking code. Checks if 0 <= idx <= len, branches to exit if not.
// Starts a new block on return.
// idx and len are already converted to full int width.
func (s *state) sliceBoundsCheck(idx, len *ssa.Value) {
if Debug['B'] != 0 {
return
}
// bounds check
cmp := s.newValue2(ssa.OpIsSliceInBounds, Types[TBOOL], idx, len)
s.check(cmp, panicslice)
}
// If cmp (a bool) is false, panic using the given function.
func (s *state) check(cmp *ssa.Value, fn *Node) {
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cmp)
b.Likely = ssa.BranchLikely
bNext := s.f.NewBlock(ssa.BlockPlain)
line := s.peekLine()
bPanic := s.panics[funcLine{fn, line}]
if bPanic == nil {
bPanic = s.f.NewBlock(ssa.BlockPlain)
s.panics[funcLine{fn, line}] = bPanic
s.startBlock(bPanic)
// The panic call takes/returns memory to ensure that the right
// memory state is observed if the panic happens.
s.rtcall(fn, false, nil)
}
b.AddEdgeTo(bNext)
b.AddEdgeTo(bPanic)
s.startBlock(bNext)
}
// rtcall issues a call to the given runtime function fn with the listed args.
// Returns a slice of results of the given result types.
// The call is added to the end of the current block.
// If returns is false, the block is marked as an exit block.
// If returns is true, the block is marked as a call block. A new block
// is started to load the return values.
func (s *state) rtcall(fn *Node, returns bool, results []*Type, args ...*ssa.Value) []*ssa.Value {
// Write args to the stack
off := Ctxt.FixedFrameSize()
for _, arg := range args {
t := arg.Type
off = Rnd(off, t.Alignment())
ptr := s.sp
if off != 0 {
ptr = s.newValue1I(ssa.OpOffPtr, t.PtrTo(), off, s.sp)
}
size := t.Size()
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, size, ptr, arg, s.mem())
off += size
}
off = Rnd(off, int64(Widthptr))
if Thearch.LinkArch.Name == "amd64p32" {
// amd64p32 wants 8-byte alignment of the start of the return values.
off = Rnd(off, 8)
}
// Issue call
call := s.newValue1A(ssa.OpStaticCall, ssa.TypeMem, fn.Sym, s.mem())
s.vars[&memVar] = call
// Finish block
b := s.endBlock()
if !returns {
b.Kind = ssa.BlockExit
b.SetControl(call)
call.AuxInt = off - Ctxt.FixedFrameSize()
if len(results) > 0 {
Fatalf("panic call can't have results")
}
return nil
}
b.Kind = ssa.BlockCall
b.SetControl(call)
bNext := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bNext)
s.startBlock(bNext)
// Keep input pointer args live across calls. This is a bandaid until 1.8.
for _, n := range s.ptrargs {
s.vars[&memVar] = s.newValue2(ssa.OpKeepAlive, ssa.TypeMem, s.variable(n, n.Type), s.mem())
}
// Load results
res := make([]*ssa.Value, len(results))
for i, t := range results {
off = Rnd(off, t.Alignment())
ptr := s.sp
if off != 0 {
ptr = s.newValue1I(ssa.OpOffPtr, Ptrto(t), off, s.sp)
}
res[i] = s.newValue2(ssa.OpLoad, t, ptr, s.mem())
off += t.Size()
}
off = Rnd(off, int64(Widthptr))
// Remember how much callee stack space we needed.
call.AuxInt = off
return res
}
// insertWBmove inserts the assignment *left = *right including a write barrier.
// t is the type being assigned.
func (s *state) insertWBmove(t *Type, left, right *ssa.Value, line int32, rightIsVolatile bool) {
// if writeBarrier.enabled {
// typedmemmove(&t, left, right)
// } else {
// *left = *right
// }
if s.noWB {
s.Fatalf("write barrier prohibited")
}
if s.WBLineno == 0 {
s.WBLineno = left.Line
}
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
aux := &ssa.ExternSymbol{Typ: Types[TBOOL], Sym: syslook("writeBarrier").Sym}
flagaddr := s.newValue1A(ssa.OpAddr, Ptrto(Types[TUINT32]), aux, s.sb)
// Load word, test word, avoiding partial register write from load byte.
flag := s.newValue2(ssa.OpLoad, Types[TUINT32], flagaddr, s.mem())
flag = s.newValue2(ssa.OpNeq32, Types[TBOOL], flag, s.constInt32(Types[TUINT32], 0))
b := s.endBlock()
b.Kind = ssa.BlockIf
b.Likely = ssa.BranchUnlikely
b.SetControl(flag)
b.AddEdgeTo(bThen)
b.AddEdgeTo(bElse)
s.startBlock(bThen)
if !rightIsVolatile {
// Issue typedmemmove call.
taddr := s.newValue1A(ssa.OpAddr, Types[TUINTPTR], &ssa.ExternSymbol{Typ: Types[TUINTPTR], Sym: typenamesym(t)}, s.sb)
s.rtcall(typedmemmove, true, nil, taddr, left, right)
} else {
// Copy to temp location if the source is volatile (will be clobbered by
// a function call). Marshaling the args to typedmemmove might clobber the
// value we're trying to move.
tmp := temp(t)
s.vars[&memVar] = s.newValue1A(ssa.OpVarDef, ssa.TypeMem, tmp, s.mem())
tmpaddr, _ := s.addr(tmp, true)
s.vars[&memVar] = s.newValue3I(ssa.OpMove, ssa.TypeMem, SizeAlignAuxInt(t), tmpaddr, right, s.mem())
// Issue typedmemmove call.
taddr := s.newValue1A(ssa.OpAddr, Types[TUINTPTR], &ssa.ExternSymbol{Typ: Types[TUINTPTR], Sym: typenamesym(t)}, s.sb)
s.rtcall(typedmemmove, true, nil, taddr, left, tmpaddr)
// Mark temp as dead.
s.vars[&memVar] = s.newValue1A(ssa.OpVarKill, ssa.TypeMem, tmp, s.mem())
}
s.endBlock().AddEdgeTo(bEnd)
s.startBlock(bElse)
s.vars[&memVar] = s.newValue3I(ssa.OpMove, ssa.TypeMem, SizeAlignAuxInt(t), left, right, s.mem())
s.endBlock().AddEdgeTo(bEnd)
s.startBlock(bEnd)
if Debug_wb > 0 {
Warnl(line, "write barrier")
}
}
// insertWBstore inserts the assignment *left = right including a write barrier.
// t is the type being assigned.
func (s *state) insertWBstore(t *Type, left, right *ssa.Value, line int32, skip skipMask) {
// store scalar fields
// if writeBarrier.enabled {
// writebarrierptr for pointer fields
// } else {
// store pointer fields
// }
if s.noWB {
s.Fatalf("write barrier prohibited")
}
if s.WBLineno == 0 {
s.WBLineno = left.Line
}
s.storeTypeScalars(t, left, right, skip)
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
aux := &ssa.ExternSymbol{Typ: Types[TBOOL], Sym: syslook("writeBarrier").Sym}
flagaddr := s.newValue1A(ssa.OpAddr, Ptrto(Types[TUINT32]), aux, s.sb)
// Load word, test word, avoiding partial register write from load byte.
flag := s.newValue2(ssa.OpLoad, Types[TUINT32], flagaddr, s.mem())
flag = s.newValue2(ssa.OpNeq32, Types[TBOOL], flag, s.constInt32(Types[TUINT32], 0))
b := s.endBlock()
b.Kind = ssa.BlockIf
b.Likely = ssa.BranchUnlikely
b.SetControl(flag)
b.AddEdgeTo(bThen)
b.AddEdgeTo(bElse)
// Issue write barriers for pointer writes.
s.startBlock(bThen)
s.storeTypePtrsWB(t, left, right)
s.endBlock().AddEdgeTo(bEnd)
// Issue regular stores for pointer writes.
s.startBlock(bElse)
s.storeTypePtrs(t, left, right)
s.endBlock().AddEdgeTo(bEnd)
s.startBlock(bEnd)
if Debug_wb > 0 {
Warnl(line, "write barrier")
}
}
// do *left = right for all scalar (non-pointer) parts of t.
func (s *state) storeTypeScalars(t *Type, left, right *ssa.Value, skip skipMask) {
switch {
case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex():
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, t.Size(), left, right, s.mem())
case t.IsPtrShaped():
// no scalar fields.
case t.IsString():
if skip&skipLen != 0 {
return
}
len := s.newValue1(ssa.OpStringLen, Types[TINT], right)
lenAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TINT]), s.config.IntSize, left)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, lenAddr, len, s.mem())
case t.IsSlice():
if skip&skipLen == 0 {
len := s.newValue1(ssa.OpSliceLen, Types[TINT], right)
lenAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TINT]), s.config.IntSize, left)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, lenAddr, len, s.mem())
}
if skip&skipCap == 0 {
cap := s.newValue1(ssa.OpSliceCap, Types[TINT], right)
capAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TINT]), 2*s.config.IntSize, left)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, capAddr, cap, s.mem())
}
case t.IsInterface():
// itab field doesn't need a write barrier (even though it is a pointer).
itab := s.newValue1(ssa.OpITab, Ptrto(Types[TUINT8]), right)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.IntSize, left, itab, s.mem())
case t.IsStruct():
n := t.NumFields()
for i := 0; i < n; i++ {
ft := t.FieldType(i)
addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
s.storeTypeScalars(ft.(*Type), addr, val, 0)
}
default:
s.Fatalf("bad write barrier type %s", t)
}
}
// do *left = right for all pointer parts of t.
func (s *state) storeTypePtrs(t *Type, left, right *ssa.Value) {
switch {
case t.IsPtrShaped():
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.PtrSize, left, right, s.mem())
case t.IsString():
ptr := s.newValue1(ssa.OpStringPtr, Ptrto(Types[TUINT8]), right)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.PtrSize, left, ptr, s.mem())
case t.IsSlice():
ptr := s.newValue1(ssa.OpSlicePtr, Ptrto(Types[TUINT8]), right)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.PtrSize, left, ptr, s.mem())
case t.IsInterface():
// itab field is treated as a scalar.
idata := s.newValue1(ssa.OpIData, Ptrto(Types[TUINT8]), right)
idataAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TUINT8]), s.config.PtrSize, left)
s.vars[&memVar] = s.newValue3I(ssa.OpStore, ssa.TypeMem, s.config.PtrSize, idataAddr, idata, s.mem())
case t.IsStruct():
n := t.NumFields()
for i := 0; i < n; i++ {
ft := t.FieldType(i)
if !haspointers(ft.(*Type)) {
continue
}
addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
s.storeTypePtrs(ft.(*Type), addr, val)
}
default:
s.Fatalf("bad write barrier type %s", t)
}
}
// do *left = right with a write barrier for all pointer parts of t.
func (s *state) storeTypePtrsWB(t *Type, left, right *ssa.Value) {
switch {
case t.IsPtrShaped():
s.rtcall(writebarrierptr, true, nil, left, right)
case t.IsString():
ptr := s.newValue1(ssa.OpStringPtr, Ptrto(Types[TUINT8]), right)
s.rtcall(writebarrierptr, true, nil, left, ptr)
case t.IsSlice():
ptr := s.newValue1(ssa.OpSlicePtr, Ptrto(Types[TUINT8]), right)
s.rtcall(writebarrierptr, true, nil, left, ptr)
case t.IsInterface():
idata := s.newValue1(ssa.OpIData, Ptrto(Types[TUINT8]), right)
idataAddr := s.newValue1I(ssa.OpOffPtr, Ptrto(Types[TUINT8]), s.config.PtrSize, left)
s.rtcall(writebarrierptr, true, nil, idataAddr, idata)
case t.IsStruct():
n := t.NumFields()
for i := 0; i < n; i++ {
ft := t.FieldType(i)
if !haspointers(ft.(*Type)) {
continue
}
addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
s.storeTypePtrsWB(ft.(*Type), addr, val)
}
default:
s.Fatalf("bad write barrier type %s", t)
}
}
// slice computes the slice v[i:j:k] and returns ptr, len, and cap of result.
// i,j,k may be nil, in which case they are set to their default value.
// t is a slice, ptr to array, or string type.
func (s *state) slice(t *Type, v, i, j, k *ssa.Value) (p, l, c *ssa.Value) {
var elemtype *Type
var ptrtype *Type
var ptr *ssa.Value
var len *ssa.Value
var cap *ssa.Value
zero := s.constInt(Types[TINT], 0)
switch {
case t.IsSlice():
elemtype = t.Elem()
ptrtype = Ptrto(elemtype)
ptr = s.newValue1(ssa.OpSlicePtr, ptrtype, v)
len = s.newValue1(ssa.OpSliceLen, Types[TINT], v)
cap = s.newValue1(ssa.OpSliceCap, Types[TINT], v)
case t.IsString():
elemtype = Types[TUINT8]
ptrtype = Ptrto(elemtype)
ptr = s.newValue1(ssa.OpStringPtr, ptrtype, v)
len = s.newValue1(ssa.OpStringLen, Types[TINT], v)
cap = len
case t.IsPtr():
if !t.Elem().IsArray() {
s.Fatalf("bad ptr to array in slice %v\n", t)
}
elemtype = t.Elem().Elem()
ptrtype = Ptrto(elemtype)
s.nilCheck(v)
ptr = v
len = s.constInt(Types[TINT], t.Elem().NumElem())
cap = len
default:
s.Fatalf("bad type in slice %v\n", t)
}
// Set default values
if i == nil {
i = zero
}
if j == nil {
j = len
}
if k == nil {
k = cap
}
// Panic if slice indices are not in bounds.
s.sliceBoundsCheck(i, j)
if j != k {
s.sliceBoundsCheck(j, k)
}
if k != cap {
s.sliceBoundsCheck(k, cap)
}
// Generate the following code assuming that indexes are in bounds.
// The conditional is to make sure that we don't generate a slice
// that points to the next object in memory.
// rlen = j-i
// rcap = k-i
// delta = i*elemsize
// if rcap == 0 {
// delta = 0
// }
// rptr = p+delta
// result = (SliceMake rptr rlen rcap)
subOp := s.ssaOp(OSUB, Types[TINT])
eqOp := s.ssaOp(OEQ, Types[TINT])
mulOp := s.ssaOp(OMUL, Types[TINT])
rlen := s.newValue2(subOp, Types[TINT], j, i)
var rcap *ssa.Value
switch {
case t.IsString():
// Capacity of the result is unimportant. However, we use
// rcap to test if we've generated a zero-length slice.
// Use length of strings for that.
rcap = rlen
case j == k:
rcap = rlen
default:
rcap = s.newValue2(subOp, Types[TINT], k, i)
}
// delta = # of elements to offset pointer by.
s.vars[&deltaVar] = i
// Generate code to set delta=0 if the resulting capacity is zero.
if !((i.Op == ssa.OpConst64 && i.AuxInt == 0) ||
(i.Op == ssa.OpConst32 && int32(i.AuxInt) == 0)) {
cmp := s.newValue2(eqOp, Types[TBOOL], rcap, zero)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.Likely = ssa.BranchUnlikely
b.SetControl(cmp)
// Generate block which zeros the delta variable.
nz := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(nz)
s.startBlock(nz)
s.vars[&deltaVar] = zero
s.endBlock()
// All done.
merge := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(merge)
nz.AddEdgeTo(merge)
s.startBlock(merge)
// TODO: use conditional moves somehow?
}
// Compute rptr = ptr + delta * elemsize
rptr := s.newValue2(ssa.OpAddPtr, ptrtype, ptr, s.newValue2(mulOp, Types[TINT], s.variable(&deltaVar, Types[TINT]), s.constInt(Types[TINT], elemtype.Width)))
delete(s.vars, &deltaVar)
return rptr, rlen, rcap
}
type u2fcvtTab struct {
geq, cvt2F, and, rsh, or, add ssa.Op
one func(*state, ssa.Type, int64) *ssa.Value
}
var u64_f64 u2fcvtTab = u2fcvtTab{
geq: ssa.OpGeq64,
cvt2F: ssa.OpCvt64to64F,
and: ssa.OpAnd64,
rsh: ssa.OpRsh64Ux64,
or: ssa.OpOr64,
add: ssa.OpAdd64F,
one: (*state).constInt64,
}
var u64_f32 u2fcvtTab = u2fcvtTab{
geq: ssa.OpGeq64,
cvt2F: ssa.OpCvt64to32F,
and: ssa.OpAnd64,
rsh: ssa.OpRsh64Ux64,
or: ssa.OpOr64,
add: ssa.OpAdd32F,
one: (*state).constInt64,
}
// Excess generality on a machine with 64-bit integer registers.
// Not used on AMD64.
var u32_f32 u2fcvtTab = u2fcvtTab{
geq: ssa.OpGeq32,
cvt2F: ssa.OpCvt32to32F,
and: ssa.OpAnd32,
rsh: ssa.OpRsh32Ux32,
or: ssa.OpOr32,
add: ssa.OpAdd32F,
one: func(s *state, t ssa.Type, x int64) *ssa.Value {
return s.constInt32(t, int32(x))
},
}
func (s *state) uint64Tofloat64(n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
return s.uintTofloat(&u64_f64, n, x, ft, tt)
}
func (s *state) uint64Tofloat32(n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
return s.uintTofloat(&u64_f32, n, x, ft, tt)
}
func (s *state) uintTofloat(cvttab *u2fcvtTab, n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
// if x >= 0 {
// result = (floatY) x
// } else {
// y = uintX(x) ; y = x & 1
// z = uintX(x) ; z = z >> 1
// z = z >> 1
// z = z | y
// result = floatY(z)
// result = result + result
// }
//
// Code borrowed from old code generator.
// What's going on: large 64-bit "unsigned" looks like
// negative number to hardware's integer-to-float
// conversion. However, because the mantissa is only
// 63 bits, we don't need the LSB, so instead we do an
// unsigned right shift (divide by two), convert, and
// double. However, before we do that, we need to be
// sure that we do not lose a "1" if that made the
// difference in the resulting rounding. Therefore, we
// preserve it, and OR (not ADD) it back in. The case
// that matters is when the eleven discarded bits are
// equal to 10000000001; that rounds up, and the 1 cannot
// be lost else it would round down if the LSB of the
// candidate mantissa is 0.
cmp := s.newValue2(cvttab.geq, Types[TBOOL], x, s.zeroVal(ft))
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cmp)
b.Likely = ssa.BranchLikely
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bAfter := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bThen)
s.startBlock(bThen)
a0 := s.newValue1(cvttab.cvt2F, tt, x)
s.vars[n] = a0
s.endBlock()
bThen.AddEdgeTo(bAfter)
b.AddEdgeTo(bElse)
s.startBlock(bElse)
one := cvttab.one(s, ft, 1)
y := s.newValue2(cvttab.and, ft, x, one)
z := s.newValue2(cvttab.rsh, ft, x, one)
z = s.newValue2(cvttab.or, ft, z, y)
a := s.newValue1(cvttab.cvt2F, tt, z)
a1 := s.newValue2(cvttab.add, tt, a, a)
s.vars[n] = a1
s.endBlock()
bElse.AddEdgeTo(bAfter)
s.startBlock(bAfter)
return s.variable(n, n.Type)
}
// referenceTypeBuiltin generates code for the len/cap builtins for maps and channels.
func (s *state) referenceTypeBuiltin(n *Node, x *ssa.Value) *ssa.Value {
if !n.Left.Type.IsMap() && !n.Left.Type.IsChan() {
s.Fatalf("node must be a map or a channel")
}
// if n == nil {
// return 0
// } else {
// // len
// return *((*int)n)
// // cap
// return *(((*int)n)+1)
// }
lenType := n.Type
nilValue := s.constNil(Types[TUINTPTR])
cmp := s.newValue2(ssa.OpEqPtr, Types[TBOOL], x, nilValue)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cmp)
b.Likely = ssa.BranchUnlikely
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bAfter := s.f.NewBlock(ssa.BlockPlain)
// length/capacity of a nil map/chan is zero
b.AddEdgeTo(bThen)
s.startBlock(bThen)
s.vars[n] = s.zeroVal(lenType)
s.endBlock()
bThen.AddEdgeTo(bAfter)
b.AddEdgeTo(bElse)
s.startBlock(bElse)
if n.Op == OLEN {
// length is stored in the first word for map/chan
s.vars[n] = s.newValue2(ssa.OpLoad, lenType, x, s.mem())
} else if n.Op == OCAP {
// capacity is stored in the second word for chan
sw := s.newValue1I(ssa.OpOffPtr, lenType.PtrTo(), lenType.Width, x)
s.vars[n] = s.newValue2(ssa.OpLoad, lenType, sw, s.mem())
} else {
s.Fatalf("op must be OLEN or OCAP")
}
s.endBlock()
bElse.AddEdgeTo(bAfter)
s.startBlock(bAfter)
return s.variable(n, lenType)
}
type f2uCvtTab struct {
ltf, cvt2U, subf ssa.Op
value func(*state, ssa.Type, float64) *ssa.Value
}
var f32_u64 f2uCvtTab = f2uCvtTab{
ltf: ssa.OpLess32F,
cvt2U: ssa.OpCvt32Fto64,
subf: ssa.OpSub32F,
value: (*state).constFloat32,
}
var f64_u64 f2uCvtTab = f2uCvtTab{
ltf: ssa.OpLess64F,
cvt2U: ssa.OpCvt64Fto64,
subf: ssa.OpSub64F,
value: (*state).constFloat64,
}
func (s *state) float32ToUint64(n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
return s.floatToUint(&f32_u64, n, x, ft, tt)
}
func (s *state) float64ToUint64(n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
return s.floatToUint(&f64_u64, n, x, ft, tt)
}
func (s *state) floatToUint(cvttab *f2uCvtTab, n *Node, x *ssa.Value, ft, tt *Type) *ssa.Value {
// if x < 9223372036854775808.0 {
// result = uintY(x)
// } else {
// y = x - 9223372036854775808.0
// z = uintY(y)
// result = z | -9223372036854775808
// }
twoToThe63 := cvttab.value(s, ft, 9223372036854775808.0)
cmp := s.newValue2(cvttab.ltf, Types[TBOOL], x, twoToThe63)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cmp)
b.Likely = ssa.BranchLikely
bThen := s.f.NewBlock(ssa.BlockPlain)
bElse := s.f.NewBlock(ssa.BlockPlain)
bAfter := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bThen)
s.startBlock(bThen)
a0 := s.newValue1(cvttab.cvt2U, tt, x)
s.vars[n] = a0
s.endBlock()
bThen.AddEdgeTo(bAfter)
b.AddEdgeTo(bElse)
s.startBlock(bElse)
y := s.newValue2(cvttab.subf, ft, x, twoToThe63)
y = s.newValue1(cvttab.cvt2U, tt, y)
z := s.constInt64(tt, -9223372036854775808)
a1 := s.newValue2(ssa.OpOr64, tt, y, z)
s.vars[n] = a1
s.endBlock()
bElse.AddEdgeTo(bAfter)
s.startBlock(bAfter)
return s.variable(n, n.Type)
}
// ifaceType returns the value for the word containing the type.
// n is the node for the interface expression.
// v is the corresponding value.
func (s *state) ifaceType(n *Node, v *ssa.Value) *ssa.Value {
byteptr := Ptrto(Types[TUINT8]) // type used in runtime prototypes for runtime type (*byte)
if n.Type.IsEmptyInterface() {
// Have *eface. The type is the first word in the struct.
return s.newValue1(ssa.OpITab, byteptr, v)
}
// Have *iface.
// The first word in the struct is the *itab.
// If the *itab is nil, return 0.
// Otherwise, the second word in the *itab is the type.
tab := s.newValue1(ssa.OpITab, byteptr, v)
s.vars[&typVar] = tab
isnonnil := s.newValue2(ssa.OpNeqPtr, Types[TBOOL], tab, s.constNil(byteptr))
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(isnonnil)
b.Likely = ssa.BranchLikely
bLoad := s.f.NewBlock(ssa.BlockPlain)
bEnd := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bLoad)
b.AddEdgeTo(bEnd)
bLoad.AddEdgeTo(bEnd)
s.startBlock(bLoad)
off := s.newValue1I(ssa.OpOffPtr, byteptr, int64(Widthptr), tab)
s.vars[&typVar] = s.newValue2(ssa.OpLoad, byteptr, off, s.mem())
s.endBlock()
s.startBlock(bEnd)
typ := s.variable(&typVar, byteptr)
delete(s.vars, &typVar)
return typ
}
// dottype generates SSA for a type assertion node.
// commaok indicates whether to panic or return a bool.
// If commaok is false, resok will be nil.
func (s *state) dottype(n *Node, commaok bool) (res, resok *ssa.Value) {
iface := s.expr(n.Left)
typ := s.ifaceType(n.Left, iface) // actual concrete type
target := s.expr(typename(n.Type)) // target type
if !isdirectiface(n.Type) {
// walk rewrites ODOTTYPE/OAS2DOTTYPE into runtime calls except for this case.
Fatalf("dottype needs a direct iface type %s", n.Type)
}
if Debug_typeassert > 0 {
Warnl(n.Lineno, "type assertion inlined")
}
// TODO: If we have a nonempty interface and its itab field is nil,
// then this test is redundant and ifaceType should just branch directly to bFail.
cond := s.newValue2(ssa.OpEqPtr, Types[TBOOL], typ, target)
b := s.endBlock()
b.Kind = ssa.BlockIf
b.SetControl(cond)
b.Likely = ssa.BranchLikely
byteptr := Ptrto(Types[TUINT8])
bOk := s.f.NewBlock(ssa.BlockPlain)
bFail := s.f.NewBlock(ssa.BlockPlain)
b.AddEdgeTo(bOk)
b.AddEdgeTo(bFail)
if !commaok {
// on failure, panic by calling panicdottype
s.startBlock(bFail)
taddr := s.newValue1A(ssa.OpAddr, byteptr, &ssa.ExternSymbol{Typ: byteptr, Sym: typenamesym(n.Left.Type)}, s.sb)
s.rtcall(panicdottype, false, nil, typ, target, taddr)
// on success, return idata field
s.startBlock(bOk)
return s.newValue1(ssa.OpIData, n.Type, iface), nil
}
// commaok is the more complicated case because we have
// a control flow merge point.
bEnd := s.f.NewBlock(ssa.BlockPlain)
// type assertion succeeded
s.startBlock(bOk)
s.vars[&idataVar] = s.newValue1(ssa.OpIData, n.Type, iface)
s.vars[&okVar] = s.constBool(true)
s.endBlock()
bOk.AddEdgeTo(bEnd)
// type assertion failed
s.startBlock(bFail)
s.vars[&idataVar] = s.constNil(byteptr)
s.vars[&okVar] = s.constBool(false)
s.endBlock()
bFail.AddEdgeTo(bEnd)
// merge point
s.startBlock(bEnd)
res = s.variable(&idataVar, byteptr)
resok = s.variable(&okVar, Types[TBOOL])
delete(s.vars, &idataVar)
delete(s.vars, &okVar)
return res, resok
}
// checkgoto checks that a goto from from to to does not
// jump into a block or jump over variable declarations.