[dev.ssa] cmd/compile/internal/ssa: add call opcodes

Add calls, particularly closure calls. Reorg SSAable variable test for converting to SSA. Change-Id: Ia75c04295e6b0b040122f97e2381836a393b7f42 Reviewed-on: https://go-review.googlesource.com/10912 Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2024-10-05 18:31:28 -06:00 · 2015-06-10 15:03:06 -07:00 · 2015-06-10 15:03:06 -07:00 · 290d8fc14a
commit 290d8fc14a
parent 81ccf508aa
8 changed files with 135 additions and 29 deletions
--- a/src/cmd/compile/internal/gc/opnames.go
+++ b/src/cmd/compile/internal/gc/opnames.go
@ -33,6 +33,7 @@ var opnames = []string{
 	OAS2MAPR:         "AS2MAPR",
 	OAS2DOTTYPE:      "AS2DOTTYPE",
 	OASOP:            "ASOP",
+	OASWB:            "ASWB",
 	OCALL:            "CALL",
 	OCALLFUNC:        "CALLFUNC",
 	OCALLMETH:        "CALLMETH",
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@ -224,8 +224,9 @@ func (s *state) stmt(n *Node) {
 			s.startBlock(t)
 		}

-	case OAS:
+	case OAS, OASWB:
 		// TODO(khr): colas?
+		// TODO: do write barrier
 		var val *ssa.Value
 		if n.Right == nil {
 			// n.Right == nil means use the zero value of the assigned type.
@ -243,15 +244,14 @@ func (s *state) stmt(n *Node) {
 		} else {
 			val = s.expr(n.Right)
 		}
-		if n.Left.Op == ONAME && !n.Left.Addrtaken && n.Left.Class&PHEAP == 0 && n.Left.Class != PEXTERN && n.Left.Class != PPARAMOUT {
-			// ssa-able variable.
+		if n.Left.Op == ONAME && canSSA(n.Left) {
+			// Update variable assignment.
 			s.vars[n.Left.Sym.Name] = val
 			return
 		}
 		// not ssa-able.  Treat as a store.
 		addr := s.addr(n.Left)
 		s.vars[".mem"] = s.newValue3(ssa.OpStore, ssa.TypeMem, nil, addr, val, s.mem())
-		// TODO: try to make more variables registerizeable.
 	case OIF:
 		cond := s.expr(n.Ntest)
 		b := s.endBlock()
@ -338,14 +338,16 @@ func (s *state) expr(n *Node) *ssa.Value {

 	switch n.Op {
 	case ONAME:
-		// TODO: remember offsets for PPARAM names
-		if n.Class == PEXTERN {
-			// global variable
-			addr := s.entryNewValue(ssa.OpGlobal, Ptrto(n.Type), n.Sym)
-			return s.newValue2(ssa.OpLoad, n.Type, nil, addr, s.mem())
+		if n.Class == PFUNC {
+			// "value" of a function is the address of the function's closure
+			return s.entryNewValue(ssa.OpGlobal, Ptrto(n.Type), funcsym(n.Sym))
 		}
-		s.argOffsets[n.Sym.Name] = n.Xoffset
-		return s.variable(n.Sym.Name, n.Type)
+		s.argOffsets[n.Sym.Name] = n.Xoffset // TODO: remember this another way?
+		if canSSA(n) {
+			return s.variable(n.Sym.Name, n.Type)
+		}
+		addr := s.addr(n)
+		return s.newValue2(ssa.OpLoad, n.Type, nil, addr, s.mem())
 	case OLITERAL:
 		switch n.Val.Ctype {
 		case CTINT:
@ -415,17 +417,25 @@ func (s *state) expr(n *Node) *ssa.Value {
 		}

 	case OCALLFUNC:
+		static := n.Left.Op == ONAME && n.Left.Class == PFUNC
+
+		// evaluate closure
+		var closure *ssa.Value
+		if !static {
+			closure = s.expr(n.Left)
+		}
+
 		// run all argument assignments
-		// TODO(khr): do we need to evaluate function first?
-		// Or is it already side-effect-free and does not require a call?
 		s.stmtList(n.List)

-		if n.Left.Op != ONAME {
-			// TODO(khr): closure calls?
-			log.Fatalf("can't handle CALLFUNC with non-ONAME fn %s", opnames[n.Left.Op])
-		}
 		bNext := s.f.NewBlock(ssa.BlockPlain)
-		call := s.newValue1(ssa.OpStaticCall, ssa.TypeMem, n.Left.Sym, s.mem())
+		var call *ssa.Value
+		if static {
+			call = s.newValue1(ssa.OpStaticCall, ssa.TypeMem, n.Left.Sym, s.mem())
+		} else {
+			entry := s.newValue2(ssa.OpLoad, s.config.Uintptr, nil, closure, s.mem())
+			call = s.newValue3(ssa.OpClosureCall, ssa.TypeMem, nil, entry, closure, s.mem())
+		}
 		b := s.endBlock()
 		b.Kind = ssa.BlockCall
 		b.Control = call
@ -448,17 +458,18 @@ func (s *state) expr(n *Node) *ssa.Value {
 func (s *state) addr(n *Node) *ssa.Value {
 	switch n.Op {
 	case ONAME:
-		if n.Class == PEXTERN {
+		switch n.Class {
+		case PEXTERN:
 			// global variable
 			return s.entryNewValue(ssa.OpGlobal, Ptrto(n.Type), n.Sym)
-		}
-		if n.Class == PPARAMOUT {
+		case PPARAMOUT:
 			// store to parameter slot
 			return s.entryNewValue1(ssa.OpOffPtr, Ptrto(n.Type), n.Xoffset, s.fp)
+		default:
+			// TODO: address of locals
+			log.Fatalf("variable address of %v not implemented", n)
+			return nil
 		}
-		// TODO: address of locals
-		log.Fatalf("variable address of %v not implemented", n)
-		return nil
 	case OINDREG:
 		// indirect off a register (TODO: always SP?)
 		// used for storing/loading arguments/returns to/from callees
@ -484,6 +495,28 @@ func (s *state) addr(n *Node) *ssa.Value {
 	}
 }

+// canSSA reports whether n is SSA-able.
+// n must be an ONAME.
+func canSSA(n *Node) bool {
+	if n.Op != ONAME {
+		log.Fatalf("canSSA passed a non-ONAME %s %v", Oconv(int(n.Op), 0), n)
+	}
+	if n.Addrtaken {
+		return false
+	}
+	if n.Class&PHEAP != 0 {
+		return false
+	}
+	if n.Class == PEXTERN {
+		return false
+	}
+	if n.Class == PPARAMOUT {
+		return false
+	}
+	return true
+	// TODO: try to make more variables SSAable.
+}
+
 // nilCheck generates nil pointer checking code.
 // Starts a new block on return.
 func (s *state) nilCheck(ptr *ssa.Value) {
@ -854,11 +887,15 @@ func genValue(v *ssa.Value) {
 		p.From.Offset = g.Offset
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = regnum(v)
-	case ssa.OpStaticCall:
+	case ssa.OpAMD64CALLstatic:
 		p := Prog(obj.ACALL)
 		p.To.Type = obj.TYPE_MEM
 		p.To.Name = obj.NAME_EXTERN
 		p.To.Sym = Linksym(v.Aux.(*Sym))
+	case ssa.OpAMD64CALLclosure:
+		p := Prog(obj.ACALL)
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = regnum(v.Args[0])
 	case ssa.OpFP, ssa.OpSP:
 		// nothing to do
 	default:
--- a/src/cmd/compile/internal/ssa/TODO
+++ b/src/cmd/compile/internal/ssa/TODO
@ -26,6 +26,7 @@ Opcodes
 - It's annoying to list the opcode both in the opcode list and an
   opInfo map entry.  Specify it one place and use go:generate to
   produce both?
+ - Write barriers

 Regalloc
 - Make less arch-dependent
@ -33,6 +34,7 @@ Regalloc
 - Allow args and return values to be ssa-able.
 - Handle 2-address instructions.
 - Floating point registers
+ - Make calls clobber all registers

 Rewrites
 - Strength reduction (both arch-indep and arch-dependent?)
@ -51,3 +53,4 @@ Common-Subexpression Elimination
 Other
 - Make go:generate less painful.  Have a subpackage that just has the
   generate commands in it?
+ - Use gc.Fatal for errors.  Add a callback to Frontend?
--- a/src/cmd/compile/internal/ssa/gen/AMD64.rules
+++ b/src/cmd/compile/internal/ssa/gen/AMD64.rules
@ -40,6 +40,9 @@
 (If (SETB cmp) yes no) -> (ULT cmp yes no)
 (If cond yes no) && cond.Op == OpAMD64MOVBload -> (NE (TESTB <TypeFlags> cond cond) yes no)

+(StaticCall [target] mem) -> (CALLstatic [target] mem)
+(ClosureCall entry closure mem) -> (CALLclosure entry closure mem)
+
 // Rules below here apply some simple optimizations after lowering.
 // TODO: Should this be a separate pass?

--- a/src/cmd/compile/internal/ssa/gen/AMD64Ops.go
+++ b/src/cmd/compile/internal/ssa/gen/AMD64Ops.go
@ -132,6 +132,10 @@ func init() {
 		{name: "MOVQloadglobal"},  // Load from aux.(GlobalOffset).  arg0 = memory
 		{name: "MOVQstoreglobal"}, // store arg0 to aux.(GlobalOffset).  arg1=memory, returns memory.

+		//TODO: set register clobber to everything?
+		{name: "CALLstatic"},                                                            // call static function.  arg0=mem, returns mem
+		{name: "CALLclosure", reg: regInfo{[]regMask{gpsp, buildReg("DX"), 0}, 0, nil}}, // call function via closure.  arg0=codeptr, arg1=closure, arg2=mem returns mem
+
 		{name: "REPMOVSB", reg: regInfo{[]regMask{buildReg("DI"), buildReg("SI"), buildReg("CX")}, buildReg("DI SI CX"), nil}}, // move arg2 bytes from arg1 to arg0.  arg3=mem, returns memory

 		{name: "ADDL", reg: gp21}, // arg0+arg1
--- a/src/cmd/compile/internal/ssa/gen/genericOps.go
+++ b/src/cmd/compile/internal/ssa/gen/genericOps.go
@ -44,8 +44,8 @@ var genericOps = []opData{
 	// Function calls.  Arguments to the call have already been written to the stack.
 	// Return values appear on the stack.  The method receiver, if any, is treated
 	// as a phantom first argument.
-	{name: "Call"},       // arg0=code pointer, arg1=context ptr, arg2=memory.  Returns memory.
-	{name: "StaticCall"}, // call function aux.(*gc.Sym), arg0=memory.  Returns memory.
+	{name: "ClosureCall"}, // arg0=code pointer, arg1=context ptr, arg2=memory.  Returns memory.
+	{name: "StaticCall"},  // call function aux.(*gc.Sym), arg0=memory.  Returns memory.

 	// Conversions
 	{name: "Convert"}, // convert arg0 to another type
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@ -82,6 +82,8 @@ const (
 	OpAMD64MOVQstoreidx8
 	OpAMD64MOVQloadglobal
 	OpAMD64MOVQstoreglobal
+	OpAMD64CALLstatic
+	OpAMD64CALLclosure
 	OpAMD64REPMOVSB
 	OpAMD64ADDL
 	OpAMD64InvertFlags
@ -103,7 +105,7 @@ const (
 	OpLoad
 	OpStore
 	OpMove
-	OpCall
+	OpClosureCall
 	OpStaticCall
 	OpConvert
 	OpConvNop
@ -553,6 +555,26 @@ var opcodeTable = [...]opInfo{
 			outputs:  []regMask{},
 		},
 	},
+	{
+		name: "CALLstatic",
+		reg: regInfo{
+			inputs:   []regMask{},
+			clobbers: 0,
+			outputs:  []regMask{},
+		},
+	},
+	{
+		name: "CALLclosure",
+		reg: regInfo{
+			inputs: []regMask{
+				4295032831,
+				4,
+				0,
+			},
+			clobbers: 0,
+			outputs:  []regMask{},
+		},
+	},
 	{
 		name: "REPMOVSB",
 		reg: regInfo{
@ -741,7 +763,7 @@ var opcodeTable = [...]opInfo{
 		generic: true,
 	},
 	{
-		name: "Call",
+		name: "ClosureCall",
 		reg: regInfo{
 			inputs:   []regMask{},
 			clobbers: 0,
--- a/src/cmd/compile/internal/ssa/rewriteAMD64.go
+++ b/src/cmd/compile/internal/ssa/rewriteAMD64.go
@ -191,6 +191,25 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
 		goto endf8ca12fe79290bc82b11cfa463bc9413
 	endf8ca12fe79290bc82b11cfa463bc9413:
 		;
+	case OpClosureCall:
+		// match: (ClosureCall entry closure mem)
+		// cond:
+		// result: (CALLclosure entry closure mem)
+		{
+			entry := v.Args[0]
+			closure := v.Args[1]
+			mem := v.Args[2]
+			v.Op = OpAMD64CALLclosure
+			v.Aux = nil
+			v.resetArgs()
+			v.AddArg(entry)
+			v.AddArg(closure)
+			v.AddArg(mem)
+			return true
+		}
+		goto endee26da781e813a3c602ccb4f7ade98c7
+	endee26da781e813a3c602ccb4f7ade98c7:
+		;
 	case OpConst:
 		// match: (Const <t> [val])
 		// cond: is64BitInt(t)
@ -743,6 +762,23 @@ func rewriteValueAMD64(v *Value, config *Config) bool {
 		goto end78e66b6fc298684ff4ac8aec5ce873c9
 	end78e66b6fc298684ff4ac8aec5ce873c9:
 		;
+	case OpStaticCall:
+		// match: (StaticCall [target] mem)
+		// cond:
+		// result: (CALLstatic [target] mem)
+		{
+			target := v.Aux
+			mem := v.Args[0]
+			v.Op = OpAMD64CALLstatic
+			v.Aux = nil
+			v.resetArgs()
+			v.Aux = target
+			v.AddArg(mem)
+			return true
+		}
+		goto endcf02eb60d90086f6c42bfdc5842b145d
+	endcf02eb60d90086f6c42bfdc5842b145d:
+		;
 	case OpStore:
 		// match: (Store ptr val mem)
 		// cond: (is64BitInt(val.Type) || isPtr(val.Type))