cmd/compile/internal/ssa: add SymEffect attribute to SSA Ops

To replace the progeffects tables for liveness analysis.

Change-Id: Idc4b990665cb0a9aa300d62cdf8ad12e51c5b991
Reviewed-on: https://go-review.googlesource.com/38083
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

src/cmd/compile/internal/ssa/gen/main.go

@@ -18,6 +18,7 @@ import (
 	"path"
 	"regexp"
 	"sort"
+	"strings"
 )
 
 type arch struct {
@@ -42,17 +43,18 @@ type opData struct {
 	typ               string // default result type
 	aux               string
 	rematerializeable bool
-	argLength         int32 // number of arguments, if -1, then this operation has a variable number of arguments
-	commutative       bool  // this operation is commutative on its first 2 arguments (e.g. addition)
-	resultInArg0      bool  // (first, if a tuple) output of v and v.Args[0] must be allocated to the same register
-	resultNotInArgs   bool  // outputs must not be allocated to the same registers as inputs
-	clobberFlags      bool  // this op clobbers flags register
-	call              bool  // is a function call
-	nilCheck          bool  // this op is a nil check on arg0
-	faultOnNilArg0    bool  // this op will fault if arg0 is nil (and aux encodes a small offset)
-	faultOnNilArg1    bool  // this op will fault if arg1 is nil (and aux encodes a small offset)
-	usesScratch       bool  // this op requires scratch memory space
-	hasSideEffects    bool  // for "reasons", not to be eliminated.  E.g., atomic store, #19182.
+	argLength         int32  // number of arguments, if -1, then this operation has a variable number of arguments
+	commutative       bool   // this operation is commutative on its first 2 arguments (e.g. addition)
+	resultInArg0      bool   // (first, if a tuple) output of v and v.Args[0] must be allocated to the same register
+	resultNotInArgs   bool   // outputs must not be allocated to the same registers as inputs
+	clobberFlags      bool   // this op clobbers flags register
+	call              bool   // is a function call
+	nilCheck          bool   // this op is a nil check on arg0
+	faultOnNilArg0    bool   // this op will fault if arg0 is nil (and aux encodes a small offset)
+	faultOnNilArg1    bool   // this op will fault if arg1 is nil (and aux encodes a small offset)
+	usesScratch       bool   // this op requires scratch memory space
+	hasSideEffects    bool   // for "reasons", not to be eliminated.  E.g., atomic store, #19182.
+	symEffect         string // effect this op has on symbol in aux
 }
 
 type blockData struct {
@@ -212,6 +214,12 @@ func genOp() {
 			if v.hasSideEffects {
 				fmt.Fprintln(w, "hasSideEffects: true,")
 			}
+			if v.symEffect != "" {
+				if !strings.HasPrefix(v.aux, "Sym") {
+					log.Fatalf("symEffect with aux %s not allowed", v.aux)
+				}
+				fmt.Fprintf(w, "symEffect: Sym%s,\n", v.symEffect)
+			}
 			if a.name == "generic" {
 				fmt.Fprintln(w, "generic:true,")
 				fmt.Fprintln(w, "},") // close op
@@ -273,6 +281,9 @@ func genOp() {
 
 	fmt.Fprintln(w, "func (o Op) UsesScratch() bool { return opcodeTable[o].usesScratch }")
 
+	fmt.Fprintln(w, "func (o Op) SymEffect() SymEffect { return opcodeTable[o].symEffect }")
+	fmt.Fprintln(w, "func (o Op) IsCall() bool { return opcodeTable[o].call }")
+
 	// generate registers
 	for _, a := range archs {
 		if a.generic {

src/cmd/compile/internal/ssa/op.go

@@ -23,18 +23,19 @@ type opInfo struct {
 	auxType           auxType
 	argLen            int32 // the number of arguments, -1 if variable length
 	asm               obj.As
-	generic           bool // this is a generic (arch-independent) opcode
-	rematerializeable bool // this op is rematerializeable
-	commutative       bool // this operation is commutative (e.g. addition)
-	resultInArg0      bool // (first, if a tuple) output of v and v.Args[0] must be allocated to the same register
-	resultNotInArgs   bool // outputs must not be allocated to the same registers as inputs
-	clobberFlags      bool // this op clobbers flags register
-	call              bool // is a function call
-	nilCheck          bool // this op is a nil check on arg0
-	faultOnNilArg0    bool // this op will fault if arg0 is nil (and aux encodes a small offset)
-	faultOnNilArg1    bool // this op will fault if arg1 is nil (and aux encodes a small offset)
-	usesScratch       bool // this op requires scratch memory space
-	hasSideEffects    bool // for "reasons", not to be eliminated.  E.g., atomic store, #19182.
+	generic           bool      // this is a generic (arch-independent) opcode
+	rematerializeable bool      // this op is rematerializeable
+	commutative       bool      // this operation is commutative (e.g. addition)
+	resultInArg0      bool      // (first, if a tuple) output of v and v.Args[0] must be allocated to the same register
+	resultNotInArgs   bool      // outputs must not be allocated to the same registers as inputs
+	clobberFlags      bool      // this op clobbers flags register
+	call              bool      // is a function call
+	nilCheck          bool      // this op is a nil check on arg0
+	faultOnNilArg0    bool      // this op will fault if arg0 is nil (and aux encodes a small offset)
+	faultOnNilArg1    bool      // this op will fault if arg1 is nil (and aux encodes a small offset)
+	usesScratch       bool      // this op requires scratch memory space
+	hasSideEffects    bool      // for "reasons", not to be eliminated.  E.g., atomic store, #19182.
+	symEffect         SymEffect // effect this op has on symbol in aux
 }
 
 type inputInfo struct {
@@ -75,6 +76,20 @@ const (
 	auxSymInt32 // aux is a symbol, auxInt is a 32-bit integer
 )
 
+// A SymEffect describes the effect that an SSA Value has on the variable
+// identified by the symbol in its Aux field.
+type SymEffect int8
+
+const (
+	SymRead SymEffect = 1 << iota
+	SymWrite
+	SymAddr
+
+	SymRdWr = SymRead | SymWrite
+
+	SymNone SymEffect = 0
+)
+
 // A ValAndOff is used by the several opcodes. It holds
 // both a value and a pointer offset.
 // A ValAndOff is intended to be encoded into an AuxInt field.

src/cmd/compile/internal/ssa/opGen.go

@@ -21852,9 +21852,11 @@ var opcodeTable = [...]opInfo{
 	},
 }
 
-func (o Op) Asm() obj.As       { return opcodeTable[o].asm }
-func (o Op) String() string    { return opcodeTable[o].name }
-func (o Op) UsesScratch() bool { return opcodeTable[o].usesScratch }
+func (o Op) Asm() obj.As          { return opcodeTable[o].asm }
+func (o Op) String() string       { return opcodeTable[o].name }
+func (o Op) UsesScratch() bool    { return opcodeTable[o].usesScratch }
+func (o Op) SymEffect() SymEffect { return opcodeTable[o].symEffect }
+func (o Op) IsCall() bool         { return opcodeTable[o].call }
 
 var registers386 = [...]Register{
 	{0, x86.REG_AX, "AX"},