go.tools/ssa: small changes accumulated during gri's vacation. :)
Method sets:
- Simplify CallCommon.
Avoid the implicit copy when calling a T method on a *T
receiver. This simplifies clients. Instead we generate
"indirection wrapper" functions that do this (like gc does).
New invariant:
m's receiver type is exactly T for all m in MethodSet(T)
- MakeInterface no longer holds the concrete type's MethodSet.
We can defer its computation this way.
- ssa.Type now just wraps a types.TypeName object.
MethodSets are computed as needed, not eagerly.
Position info:
- new CanonicalPos utility maps ast.Expr to canonical
token.Pos, as returned by {Instruction,Value}.Pos() methods.
- Don't set posn for implicit operations (e.g. varargs array alloc)
- Set position info for ChangeInterface and Slice instructions.
Cosmetic:
- add Member.Token() method
- simplify isPointer
- Omit words "interface", "slice" when printing MakeInterface,
MakeSlice; the type is enough.
- Comments on PathEnclosingInterval.
- Remove Function.FullName() where implicit String() suffices.
Also:
- Exposed NewLiteral to clients.
- Added ssa.Instruction.Parent() *Function
Added ssa.BasicBlock.Parent() *Function.
Added Sanity checks for above.
R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/10166045
diff --git a/ssa/ssa.go b/ssa/ssa.go
index ad060f1..12d3eb8 100644
--- a/ssa/ssa.go
+++ b/ssa/ssa.go
@@ -17,15 +17,16 @@
// A Program is a partial or complete Go program converted to SSA form.
//
type Program struct {
- Files *token.FileSet // position information for the files of this Program [TODO: rename Fset]
- Packages map[string]*Package // all loaded Packages, keyed by import path [TODO rename packagesByPath]
- packages map[*types.Package]*Package // all loaded Packages, keyed by object [TODO rename Packages]
- Builtins map[types.Object]*Builtin // all built-in functions, keyed by typechecker objects.
+ Files *token.FileSet // position information for the files of this Program [TODO: rename Fset]
+ Packages map[string]*Package // all loaded Packages, keyed by import path [TODO rename packagesByPath]
+ packages map[*types.Package]*Package // all loaded Packages, keyed by object [TODO rename Packages]
+ Builtins map[types.Object]*Builtin // all built-in functions, keyed by typechecker objects.
+ concreteMethods map[*types.Func]*Function // maps named concrete methods to their code
+ mode BuilderMode // set of mode bits for SSA construction
- methodSets map[types.Type]MethodSet // concrete method sets for all needed types [TODO(adonovan): de-dup]
- methodSetsMu sync.Mutex // serializes all accesses to methodSets
- concreteMethods map[*types.Func]*Function // maps named concrete methods to their code
- mode BuilderMode // set of mode bits for SSA construction
+ methodSetsMu sync.Mutex // guards methodSets, indirectionWrappers
+ methodSets map[types.Type]MethodSet // concrete method sets for all needed types [TODO(adonovan): de-dup]
+ indirectionWrappers map[*Function]*Function // func(*T) wrappers for T-methods
}
// A Package is a single analyzed Go package containing Members for
@@ -51,10 +52,11 @@
// const, var, func and type declarations respectively.
//
type Member interface {
- Name() string // the declared name of the package member
- String() string // human-readable information about the value
- Pos() token.Pos // position of member's declaration, if known
- Type() types.Type // the type of the package member
+ Name() string // the declared name of the package member
+ String() string // human-readable information about the value
+ Pos() token.Pos // position of member's declaration, if known
+ Type() types.Type // the type of the package member
+ Token() token.Token // token.{VAR,FUNC,CONST,TYPE}
}
// An Id identifies the name of a field of a struct type, or the name
@@ -77,20 +79,21 @@
Name string
}
-// A MethodSet contains all the methods for a particular type.
+// A MethodSet contains all the methods for a particular type T.
// The method sets for T and *T are distinct entities.
-// The methods for a non-pointer type T all have receiver type T, but
-// the methods for pointer type *T may have receiver type *T or T.
+//
+// All methods in the method set for T have a receiver type of exactly
+// T. The method set of *T may contain synthetic indirection methods
+// that wrap methods whose receiver type is T.
//
type MethodSet map[Id]*Function
-// A Type is a Member of a Package representing the name, underlying
-// type and method set of a named type declared at package scope.
+// A Type is a Member of a Package representing a package-level named type.
+//
+// Type() returns a *types.Named.
//
type Type struct {
- NamedType *types.Named
- Methods MethodSet // concrete method set of N
- PtrMethods MethodSet // concrete method set of (*N)
+ Object *types.TypeName
}
// A Constant is a Member of Package representing a package-level
@@ -190,6 +193,10 @@
// memory 'local int' and a definition of a pointer y.)
String() string
+ // Parent returns the function to which this instruction
+ // belongs.
+ Parent() *Function
+
// Block returns the basic block to which this instruction
// belongs.
Block() *BasicBlock
@@ -299,7 +306,7 @@
type BasicBlock struct {
Index int // index of this block within Func.Blocks
Comment string // optional label; no semantic significance
- Func *Function // containing function
+ parent *Function // parent function
Instrs []Instruction // instructions in order
Preds, Succs []*BasicBlock // predecessors and successors
succs2 [2]*BasicBlock // initial space for Succs.
@@ -327,10 +334,10 @@
// belongs to an enclosing function.
//
type Capture struct {
- name string
- typ types.Type
- pos token.Pos
-
+ name string
+ typ types.Type
+ pos token.Pos
+ parent *Function
referrers []Instruction
// Transiently needed during building.
@@ -340,10 +347,10 @@
// A Parameter represents an input parameter of a function.
//
type Parameter struct {
- name string
- typ types.Type
- pos token.Pos
-
+ name string
+ typ types.Type
+ pos token.Pos
+ parent *Function
referrers []Instruction
}
@@ -584,8 +591,12 @@
// This operation cannot fail. Use TypeAssert for interface
// conversions that may fail dynamically.
//
-// Pos() returns the ast.CallExpr.Lparen, if the instruction arose
-// from an explicit conversion in the source.
+// Pos() returns the ast.CallExpr.Lparen if the instruction arose from
+// an explicit T(e) conversion; the ast.TypeAssertExpr.Lparen if the
+// instruction arose from an explicit e.(T) operation; or token.NoPos
+// otherwise.
+//
+// TODO(adonovan) what about the nil case of e = e.(E)? Test.
//
// Example printed form:
// t1 = change interface interface{} <- I (t0)
@@ -596,7 +607,9 @@
}
// MakeInterface constructs an instance of an interface type from a
-// value and its method-set.
+// value of a concrete type.
+//
+// Use Program.MethodSet(X.Type()) to find the method-set of X.
//
// To construct the zero value of an interface type T, use:
// &Literal{exact.MakeNil(), T}
@@ -605,12 +618,12 @@
// from an explicit conversion in the source.
//
// Example printed form:
-// t1 = make interface interface{} <- int (42:int)
+// t1 = make interface{} <- int (42:int)
+// t2 = make Stringer <- t0
//
type MakeInterface struct {
Register
- X Value
- Methods MethodSet // method set of (non-interface) X
+ X Value
}
// The MakeClosure instruction yields a closure value whose code is
@@ -641,6 +654,7 @@
//
// Example printed form:
// t1 = make map[string]int t0
+// t1 = make StringIntMap t0
//
type MakeMap struct {
Register
@@ -657,6 +671,7 @@
//
// Example printed form:
// t0 = make chan int 0
+// t0 = make IntChan 0
//
type MakeChan struct {
Register
@@ -677,7 +692,8 @@
// created it.
//
// Example printed form:
-// t1 = make slice []string 1:int t0
+// t1 = make []string 1:int t0
+// t1 = make StringSlice 1:int t0
//
type MakeSlice struct {
Register
@@ -905,6 +921,11 @@
// Type() reflects the actual type of the result, possibly a
// 2-types.Tuple; AssertedType is the asserted type.
//
+// Pos() returns the ast.CallExpr.Lparen if the instruction arose from
+// an explicit T(e) conversion; the ast.TypeAssertExpr.Lparen if the
+// instruction arose from an explicit e.(T) operation; or token.NoPos
+// otherwise.
+//
// Example printed form:
// t1 = typeassert t0.(int)
// t3 = typeassert,ok t2.(T)
@@ -1168,10 +1189,6 @@
// receiver but the first true argument. Func is not used in this
// mode.
//
-// If the called method's receiver has non-pointer type T, but the
-// receiver supplied by the interface value has type *T, an implicit
-// load (copy) operation is performed.
-//
// Example printed form:
// t1 = invoke t0.String()
// go invoke t3.Run(t2)
@@ -1244,21 +1261,25 @@
func (v *Capture) Name() string { return v.name }
func (v *Capture) Referrers() *[]Instruction { return &v.referrers }
func (v *Capture) Pos() token.Pos { return v.pos }
+func (v *Capture) Parent() *Function { return v.parent }
func (v *Global) Type() types.Type { return v.typ }
func (v *Global) Name() string { return v.name }
func (v *Global) Pos() token.Pos { return v.pos }
func (*Global) Referrers() *[]Instruction { return nil }
+func (v *Global) Token() token.Token { return token.VAR }
func (v *Function) Name() string { return v.name }
func (v *Function) Type() types.Type { return v.Signature }
func (v *Function) Pos() token.Pos { return v.pos }
func (*Function) Referrers() *[]Instruction { return nil }
+func (v *Function) Token() token.Token { return token.FUNC }
func (v *Parameter) Type() types.Type { return v.typ }
func (v *Parameter) Name() string { return v.name }
func (v *Parameter) Referrers() *[]Instruction { return &v.referrers }
func (v *Parameter) Pos() token.Pos { return v.pos }
+func (v *Parameter) Parent() *Function { return v.parent }
func (v *Alloc) Type() types.Type { return v.typ }
func (v *Alloc) Name() string { return v.name }
@@ -1274,18 +1295,21 @@
func (v *Register) Pos() token.Pos { return v.pos }
func (v *Register) setPos(pos token.Pos) { v.pos = pos }
+func (v *anInstruction) Parent() *Function { return v.block.parent }
func (v *anInstruction) Block() *BasicBlock { return v.block }
func (v *anInstruction) SetBlock(block *BasicBlock) { v.block = block }
-func (t *Type) Name() string { return t.NamedType.Obj().Name() }
-func (t *Type) Pos() token.Pos { return t.NamedType.Obj().Pos() }
-func (t *Type) String() string { return t.Name() }
-func (t *Type) Type() types.Type { return t.NamedType }
+func (t *Type) Name() string { return t.Object.Name() }
+func (t *Type) Pos() token.Pos { return t.Object.Pos() }
+func (t *Type) String() string { return t.Name() }
+func (t *Type) Type() types.Type { return t.Object.Type() }
+func (t *Type) Token() token.Token { return token.TYPE }
-func (c *Constant) Name() string { return c.name }
-func (c *Constant) Pos() token.Pos { return c.pos }
-func (c *Constant) String() string { return c.Name() }
-func (c *Constant) Type() types.Type { return c.Value.Type() }
+func (c *Constant) Name() string { return c.name }
+func (c *Constant) Pos() token.Pos { return c.pos }
+func (c *Constant) String() string { return c.Name() }
+func (c *Constant) Type() types.Type { return c.Value.Type() }
+func (c *Constant) Token() token.Token { return token.CONST }
// Func returns the package-level function of the specified name,
// or nil if not found.
@@ -1335,7 +1359,8 @@
}
// Package returns the SSA package corresponding to the specified
-// type-checker package object. It returns nil if not found.
+// type-checker package object.
+// It returns nil if no such SSA package has been created.
//
func (prog *Program) Package(pkg *types.Package) *Package {
return prog.packages[pkg]
