diff options
Diffstat (limited to 'vendor/golang.org/x/tools/go/ssa/emit.go')
| -rw-r--r-- | vendor/golang.org/x/tools/go/ssa/emit.go | 614 |
1 files changed, 0 insertions, 614 deletions
diff --git a/vendor/golang.org/x/tools/go/ssa/emit.go b/vendor/golang.org/x/tools/go/ssa/emit.go deleted file mode 100644 index c664ff8..0000000 --- a/vendor/golang.org/x/tools/go/ssa/emit.go +++ /dev/null @@ -1,614 +0,0 @@ -// Copyright 2013 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 ssa - -// Helpers for emitting SSA instructions. - -import ( - "fmt" - "go/ast" - "go/token" - "go/types" - - "golang.org/x/tools/internal/typeparams" -) - -// emitAlloc emits to f a new Alloc instruction allocating a variable -// of type typ. -// -// The caller must set Alloc.Heap=true (for an heap-allocated variable) -// or add the Alloc to f.Locals (for a frame-allocated variable). -// -// During building, a variable in f.Locals may have its Heap flag -// set when it is discovered that its address is taken. -// These Allocs are removed from f.Locals at the end. -// -// The builder should generally call one of the emit{New,Local,LocalVar} wrappers instead. -func emitAlloc(f *Function, typ types.Type, pos token.Pos, comment string) *Alloc { - v := &Alloc{Comment: comment} - v.setType(types.NewPointer(typ)) - v.setPos(pos) - f.emit(v) - return v -} - -// emitNew emits to f a new Alloc instruction heap-allocating a -// variable of type typ. pos is the optional source location. -func emitNew(f *Function, typ types.Type, pos token.Pos, comment string) *Alloc { - alloc := emitAlloc(f, typ, pos, comment) - alloc.Heap = true - return alloc -} - -// emitLocal creates a local var for (t, pos, comment) and -// emits an Alloc instruction for it. -// -// (Use this function or emitNew for synthetic variables; -// for source-level variables in the same function, use emitLocalVar.) -func emitLocal(f *Function, t types.Type, pos token.Pos, comment string) *Alloc { - local := emitAlloc(f, t, pos, comment) - f.Locals = append(f.Locals, local) - return local -} - -// emitLocalVar creates a local var for v and emits an Alloc instruction for it. -// Subsequent calls to f.lookup(v) return it. -// It applies the appropriate generic instantiation to the type. -func emitLocalVar(f *Function, v *types.Var) *Alloc { - alloc := emitLocal(f, f.typ(v.Type()), v.Pos(), v.Name()) - f.vars[v] = alloc - return alloc -} - -// emitLoad emits to f an instruction to load the address addr into a -// new temporary, and returns the value so defined. -func emitLoad(f *Function, addr Value) *UnOp { - v := &UnOp{Op: token.MUL, X: addr} - v.setType(typeparams.MustDeref(addr.Type())) - f.emit(v) - return v -} - -// emitDebugRef emits to f a DebugRef pseudo-instruction associating -// expression e with value v. -func emitDebugRef(f *Function, e ast.Expr, v Value, isAddr bool) { - if !f.debugInfo() { - return // debugging not enabled - } - if v == nil || e == nil { - panic("nil") - } - var obj types.Object - e = unparen(e) - if id, ok := e.(*ast.Ident); ok { - if isBlankIdent(id) { - return - } - obj = f.objectOf(id) - switch obj.(type) { - case *types.Nil, *types.Const, *types.Builtin: - return - } - } - f.emit(&DebugRef{ - X: v, - Expr: e, - IsAddr: isAddr, - object: obj, - }) -} - -// emitArith emits to f code to compute the binary operation op(x, y) -// where op is an eager shift, logical or arithmetic operation. -// (Use emitCompare() for comparisons and Builder.logicalBinop() for -// non-eager operations.) -func emitArith(f *Function, op token.Token, x, y Value, t types.Type, pos token.Pos) Value { - switch op { - case token.SHL, token.SHR: - x = emitConv(f, x, t) - // y may be signed or an 'untyped' constant. - - // There is a runtime panic if y is signed and <0. Instead of inserting a check for y<0 - // and converting to an unsigned value (like the compiler) leave y as is. - - if isUntyped(y.Type().Underlying()) { - // Untyped conversion: - // Spec https://go.dev/ref/spec#Operators: - // The right operand in a shift expression must have integer type or be an untyped constant - // representable by a value of type uint. - y = emitConv(f, y, types.Typ[types.Uint]) - } - - case token.ADD, token.SUB, token.MUL, token.QUO, token.REM, token.AND, token.OR, token.XOR, token.AND_NOT: - x = emitConv(f, x, t) - y = emitConv(f, y, t) - - default: - panic("illegal op in emitArith: " + op.String()) - - } - v := &BinOp{ - Op: op, - X: x, - Y: y, - } - v.setPos(pos) - v.setType(t) - return f.emit(v) -} - -// emitCompare emits to f code compute the boolean result of -// comparison 'x op y'. -func emitCompare(f *Function, op token.Token, x, y Value, pos token.Pos) Value { - xt := x.Type().Underlying() - yt := y.Type().Underlying() - - // Special case to optimise a tagless SwitchStmt so that - // these are equivalent - // switch { case e: ...} - // switch true { case e: ... } - // if e==true { ... } - // even in the case when e's type is an interface. - // TODO(adonovan): opt: generalise to x==true, false!=y, etc. - if x == vTrue && op == token.EQL { - if yt, ok := yt.(*types.Basic); ok && yt.Info()&types.IsBoolean != 0 { - return y - } - } - - if types.Identical(xt, yt) { - // no conversion necessary - } else if isNonTypeParamInterface(x.Type()) { - y = emitConv(f, y, x.Type()) - } else if isNonTypeParamInterface(y.Type()) { - x = emitConv(f, x, y.Type()) - } else if _, ok := x.(*Const); ok { - x = emitConv(f, x, y.Type()) - } else if _, ok := y.(*Const); ok { - y = emitConv(f, y, x.Type()) - } else { - // other cases, e.g. channels. No-op. - } - - v := &BinOp{ - Op: op, - X: x, - Y: y, - } - v.setPos(pos) - v.setType(tBool) - return f.emit(v) -} - -// isValuePreserving returns true if a conversion from ut_src to -// ut_dst is value-preserving, i.e. just a change of type. -// Precondition: neither argument is a named or alias type. -func isValuePreserving(ut_src, ut_dst types.Type) bool { - // Identical underlying types? - if types.IdenticalIgnoreTags(ut_dst, ut_src) { - return true - } - - switch ut_dst.(type) { - case *types.Chan: - // Conversion between channel types? - _, ok := ut_src.(*types.Chan) - return ok - - case *types.Pointer: - // Conversion between pointers with identical base types? - _, ok := ut_src.(*types.Pointer) - return ok - } - return false -} - -// emitConv emits to f code to convert Value val to exactly type typ, -// and returns the converted value. Implicit conversions are required -// by language assignability rules in assignments, parameter passing, -// etc. -func emitConv(f *Function, val Value, typ types.Type) Value { - t_src := val.Type() - - // Identical types? Conversion is a no-op. - if types.Identical(t_src, typ) { - return val - } - ut_dst := typ.Underlying() - ut_src := t_src.Underlying() - - // Conversion to, or construction of a value of, an interface type? - if isNonTypeParamInterface(typ) { - // Interface name change? - if isValuePreserving(ut_src, ut_dst) { - c := &ChangeType{X: val} - c.setType(typ) - return f.emit(c) - } - - // Assignment from one interface type to another? - if isNonTypeParamInterface(t_src) { - c := &ChangeInterface{X: val} - c.setType(typ) - return f.emit(c) - } - - // Untyped nil constant? Return interface-typed nil constant. - if ut_src == tUntypedNil { - return zeroConst(typ) - } - - // Convert (non-nil) "untyped" literals to their default type. - if t, ok := ut_src.(*types.Basic); ok && t.Info()&types.IsUntyped != 0 { - val = emitConv(f, val, types.Default(ut_src)) - } - - // Record the types of operands to MakeInterface, if - // non-parameterized, as they are the set of runtime types. - t := val.Type() - if f.typeparams.Len() == 0 || !f.Prog.isParameterized(t) { - addRuntimeType(f.Prog, t) - } - - mi := &MakeInterface{X: val} - mi.setType(typ) - return f.emit(mi) - } - - // In the common case, the typesets of src and dst are singletons - // and we emit an appropriate conversion. But if either contains - // a type parameter, the conversion may represent a cross product, - // in which case which we emit a MultiConvert. - dst_terms := typeSetOf(ut_dst) - src_terms := typeSetOf(ut_src) - - // conversionCase describes an instruction pattern that maybe emitted to - // model d <- s for d in dst_terms and s in src_terms. - // Multiple conversions can match the same pattern. - type conversionCase uint8 - const ( - changeType conversionCase = 1 << iota - sliceToArray - sliceToArrayPtr - sliceTo0Array - sliceTo0ArrayPtr - convert - ) - // classify the conversion case of a source type us to a destination type ud. - // us and ud are underlying types (not *Named or *Alias) - classify := func(us, ud types.Type) conversionCase { - // Just a change of type, but not value or representation? - if isValuePreserving(us, ud) { - return changeType - } - - // Conversion from slice to array or slice to array pointer? - if slice, ok := us.(*types.Slice); ok { - var arr *types.Array - var ptr bool - // Conversion from slice to array pointer? - switch d := ud.(type) { - case *types.Array: - arr = d - case *types.Pointer: - arr, _ = d.Elem().Underlying().(*types.Array) - ptr = true - } - if arr != nil && types.Identical(slice.Elem(), arr.Elem()) { - if arr.Len() == 0 { - if ptr { - return sliceTo0ArrayPtr - } else { - return sliceTo0Array - } - } - if ptr { - return sliceToArrayPtr - } else { - return sliceToArray - } - } - } - - // The only remaining case in well-typed code is a representation- - // changing conversion of basic types (possibly with []byte/[]rune). - if !isBasic(us) && !isBasic(ud) { - panic(fmt.Sprintf("in %s: cannot convert term %s (%s [within %s]) to type %s [within %s]", f, val, val.Type(), us, typ, ud)) - } - return convert - } - - var classifications conversionCase - for _, s := range src_terms { - us := s.Type().Underlying() - for _, d := range dst_terms { - ud := d.Type().Underlying() - classifications |= classify(us, ud) - } - } - if classifications == 0 { - panic(fmt.Sprintf("in %s: cannot convert %s (%s) to %s", f, val, val.Type(), typ)) - } - - // Conversion of a compile-time constant value? - if c, ok := val.(*Const); ok { - // Conversion to a basic type? - if isBasic(ut_dst) { - // Conversion of a compile-time constant to - // another constant type results in a new - // constant of the destination type and - // (initially) the same abstract value. - // We don't truncate the value yet. - return NewConst(c.Value, typ) - } - // Can we always convert from zero value without panicking? - const mayPanic = sliceToArray | sliceToArrayPtr - if c.Value == nil && classifications&mayPanic == 0 { - return NewConst(nil, typ) - } - - // We're converting from constant to non-constant type, - // e.g. string -> []byte/[]rune. - } - - switch classifications { - case changeType: // representation-preserving change - c := &ChangeType{X: val} - c.setType(typ) - return f.emit(c) - - case sliceToArrayPtr, sliceTo0ArrayPtr: // slice to array pointer - c := &SliceToArrayPointer{X: val} - c.setType(typ) - return f.emit(c) - - case sliceToArray: // slice to arrays (not zero-length) - ptype := types.NewPointer(typ) - p := &SliceToArrayPointer{X: val} - p.setType(ptype) - x := f.emit(p) - unOp := &UnOp{Op: token.MUL, X: x} - unOp.setType(typ) - return f.emit(unOp) - - case sliceTo0Array: // slice to zero-length arrays (constant) - return zeroConst(typ) - - case convert: // representation-changing conversion - c := &Convert{X: val} - c.setType(typ) - return f.emit(c) - - default: // multiple conversion - c := &MultiConvert{X: val, from: src_terms, to: dst_terms} - c.setType(typ) - return f.emit(c) - } -} - -// emitTypeCoercion emits to f code to coerce the type of a -// Value v to exactly type typ, and returns the coerced value. -// -// Requires that coercing v.Typ() to typ is a value preserving change. -// -// Currently used only when v.Type() is a type instance of typ or vice versa. -// A type v is a type instance of a type t if there exists a -// type parameter substitution σ s.t. σ(v) == t. Example: -// -// σ(func(T) T) == func(int) int for σ == [T ↦ int] -// -// This happens in instantiation wrappers for conversion -// from an instantiation to a parameterized type (and vice versa) -// with σ substituting f.typeparams by f.typeargs. -func emitTypeCoercion(f *Function, v Value, typ types.Type) Value { - if types.Identical(v.Type(), typ) { - return v // no coercion needed - } - // TODO(taking): for instances should we record which side is the instance? - c := &ChangeType{ - X: v, - } - c.setType(typ) - f.emit(c) - return c -} - -// emitStore emits to f an instruction to store value val at location -// addr, applying implicit conversions as required by assignability rules. -func emitStore(f *Function, addr, val Value, pos token.Pos) *Store { - typ := typeparams.MustDeref(addr.Type()) - s := &Store{ - Addr: addr, - Val: emitConv(f, val, typ), - pos: pos, - } - f.emit(s) - return s -} - -// emitJump emits to f a jump to target, and updates the control-flow graph. -// Postcondition: f.currentBlock is nil. -func emitJump(f *Function, target *BasicBlock) { - b := f.currentBlock - b.emit(new(Jump)) - addEdge(b, target) - f.currentBlock = nil -} - -// emitIf emits to f a conditional jump to tblock or fblock based on -// cond, and updates the control-flow graph. -// Postcondition: f.currentBlock is nil. -func emitIf(f *Function, cond Value, tblock, fblock *BasicBlock) { - b := f.currentBlock - b.emit(&If{Cond: cond}) - addEdge(b, tblock) - addEdge(b, fblock) - f.currentBlock = nil -} - -// emitExtract emits to f an instruction to extract the index'th -// component of tuple. It returns the extracted value. -func emitExtract(f *Function, tuple Value, index int) Value { - e := &Extract{Tuple: tuple, Index: index} - e.setType(tuple.Type().(*types.Tuple).At(index).Type()) - return f.emit(e) -} - -// emitTypeAssert emits to f a type assertion value := x.(t) and -// returns the value. x.Type() must be an interface. -func emitTypeAssert(f *Function, x Value, t types.Type, pos token.Pos) Value { - a := &TypeAssert{X: x, AssertedType: t} - a.setPos(pos) - a.setType(t) - return f.emit(a) -} - -// emitTypeTest emits to f a type test value,ok := x.(t) and returns -// a (value, ok) tuple. x.Type() must be an interface. -func emitTypeTest(f *Function, x Value, t types.Type, pos token.Pos) Value { - a := &TypeAssert{ - X: x, - AssertedType: t, - CommaOk: true, - } - a.setPos(pos) - a.setType(types.NewTuple( - newVar("value", t), - varOk, - )) - return f.emit(a) -} - -// emitTailCall emits to f a function call in tail position. The -// caller is responsible for all fields of 'call' except its type. -// Intended for wrapper methods. -// Precondition: f does/will not use deferred procedure calls. -// Postcondition: f.currentBlock is nil. -func emitTailCall(f *Function, call *Call) { - tresults := f.Signature.Results() - nr := tresults.Len() - if nr == 1 { - call.typ = tresults.At(0).Type() - } else { - call.typ = tresults - } - tuple := f.emit(call) - var ret Return - switch nr { - case 0: - // no-op - case 1: - ret.Results = []Value{tuple} - default: - for i := 0; i < nr; i++ { - v := emitExtract(f, tuple, i) - // TODO(adonovan): in principle, this is required: - // v = emitConv(f, o.Type, f.Signature.Results[i].Type) - // but in practice emitTailCall is only used when - // the types exactly match. - ret.Results = append(ret.Results, v) - } - } - f.emit(&ret) - f.currentBlock = nil -} - -// emitImplicitSelections emits to f code to apply the sequence of -// implicit field selections specified by indices to base value v, and -// returns the selected value. -// -// If v is the address of a struct, the result will be the address of -// a field; if it is the value of a struct, the result will be the -// value of a field. -func emitImplicitSelections(f *Function, v Value, indices []int, pos token.Pos) Value { - for _, index := range indices { - if isPointerCore(v.Type()) { - fld := fieldOf(typeparams.MustDeref(v.Type()), index) - instr := &FieldAddr{ - X: v, - Field: index, - } - instr.setPos(pos) - instr.setType(types.NewPointer(fld.Type())) - v = f.emit(instr) - // Load the field's value iff indirectly embedded. - if isPointerCore(fld.Type()) { - v = emitLoad(f, v) - } - } else { - fld := fieldOf(v.Type(), index) - instr := &Field{ - X: v, - Field: index, - } - instr.setPos(pos) - instr.setType(fld.Type()) - v = f.emit(instr) - } - } - return v -} - -// emitFieldSelection emits to f code to select the index'th field of v. -// -// If wantAddr, the input must be a pointer-to-struct and the result -// will be the field's address; otherwise the result will be the -// field's value. -// Ident id is used for position and debug info. -func emitFieldSelection(f *Function, v Value, index int, wantAddr bool, id *ast.Ident) Value { - if isPointerCore(v.Type()) { - fld := fieldOf(typeparams.MustDeref(v.Type()), index) - instr := &FieldAddr{ - X: v, - Field: index, - } - instr.setPos(id.Pos()) - instr.setType(types.NewPointer(fld.Type())) - v = f.emit(instr) - // Load the field's value iff we don't want its address. - if !wantAddr { - v = emitLoad(f, v) - } - } else { - fld := fieldOf(v.Type(), index) - instr := &Field{ - X: v, - Field: index, - } - instr.setPos(id.Pos()) - instr.setType(fld.Type()) - v = f.emit(instr) - } - emitDebugRef(f, id, v, wantAddr) - return v -} - -// createRecoverBlock emits to f a block of code to return after a -// recovered panic, and sets f.Recover to it. -// -// If f's result parameters are named, the code loads and returns -// their current values, otherwise it returns the zero values of their -// type. -// -// Idempotent. -func createRecoverBlock(f *Function) { - if f.Recover != nil { - return // already created - } - saved := f.currentBlock - - f.Recover = f.newBasicBlock("recover") - f.currentBlock = f.Recover - - var results []Value - // Reload NRPs to form value tuple. - for _, nr := range f.results { - results = append(results, emitLoad(f, nr)) - } - - f.emit(&Return{Results: results}) - - f.currentBlock = saved -} |