cmd/compile: intrinsify runtime.getcallerpc on arm64

Add a compiler intrinsic for getcallerpc on arm64 for better code generation.

Change-Id: I897e670a2b8ffa1a8c2fdc638f5b2c44bda26318
Reviewed-on: https://go-review.googlesource.com/109276
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/asm/internal/asm/asm.go

@@ -486,7 +486,7 @@ func (p *Parser) asmInstruction(op obj.As, cond string, a []obj.Addr) {
 	case 0:
 		// Nothing to do.
 	case 1:
-		if p.arch.UnaryDst[op] || op == obj.ARET {
+		if p.arch.UnaryDst[op] || op == obj.ARET || op == obj.AGETCALLERPC {
 			// prog.From is no address.
 			prog.To = a[0]
 		} else {

src/cmd/compile/internal/arm64/ssa.go

@@ -835,6 +835,10 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.From.Name = obj.NAME_PARAM
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
+	case ssa.OpARM64LoweredGetCallerPC:
+		p := s.Prog(obj.AGETCALLERPC)
+		p.To.Type = obj.TYPE_REG
+		p.To.Reg = v.Reg()
 	case ssa.OpARM64FlagEQ,
 		ssa.OpARM64FlagLT_ULT,
 		ssa.OpARM64FlagLT_UGT,

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

@@ -2833,7 +2833,7 @@ func init() {
 	addF("runtime", "getcallerpc",
 		func(s *state, n *Node, args []*ssa.Value) *ssa.Value {
 			return s.newValue0(ssa.OpGetCallerPC, s.f.Config.Types.Uintptr)
-		}, sys.AMD64, sys.I386)
+		}, sys.AMD64, sys.I386, sys.ARM64)
 
 	add("runtime", "getcallersp",
 		func(s *state, n *Node, args []*ssa.Value) *ssa.Value {

src/cmd/compile/internal/ssa/gen/ARM64.rules

@@ -505,6 +505,7 @@
 // pseudo-ops
 (GetClosurePtr) -> (LoweredGetClosurePtr)
 (GetCallerSP) -> (LoweredGetCallerSP)
+(GetCallerPC) -> (LoweredGetCallerPC)
 
 // Absorb pseudo-ops into blocks.
 (If (Equal cc) yes no) -> (EQ cc yes no)

src/cmd/compile/internal/ssa/gen/ARM64Ops.go

@@ -527,6 +527,12 @@ func init() {
 		// LoweredGetCallerSP returns the SP of the caller of the current function.
 		{name: "LoweredGetCallerSP", reg: gp01, rematerializeable: true},
 
+		// LoweredGetCallerPC evaluates to the PC to which its "caller" will return.
+		// I.e., if f calls g "calls" getcallerpc,
+		// the result should be the PC within f that g will return to.
+		// See runtime/stubs.go for a more detailed discussion.
+		{name: "LoweredGetCallerPC", reg: gp01, rematerializeable: true},
+
 		// Constant flag values. For any comparison, there are 5 possible
 		// outcomes: the three from the signed total order (<,==,>) and the
 		// three from the unsigned total order. The == cases overlap.

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

@@ -1253,6 +1253,7 @@ const (
 	OpARM64LoweredMove
 	OpARM64LoweredGetClosurePtr
 	OpARM64LoweredGetCallerSP
+	OpARM64LoweredGetCallerPC
 	OpARM64FlagEQ
 	OpARM64FlagLT_ULT
 	OpARM64FlagLT_UGT
@@ -16394,6 +16395,16 @@ var opcodeTable = [...]opInfo{
 			},
 		},
 	},
+	{
+		name:              "LoweredGetCallerPC",
+		argLen:            0,
+		rematerializeable: true,
+		reg: regInfo{
+			outputs: []outputInfo{
+				{0, 670826495}, // R0 R1 R2 R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 R15 R16 R17 R19 R20 R21 R22 R23 R24 R25 R26 R30
+			},
+		},
+	},
 	{
 		name:   "FlagEQ",
 		argLen: 0,

src/cmd/compile/internal/ssa/rewriteARM64.go

@@ -515,6 +515,8 @@ func rewriteValueARM64(v *Value) bool {
 		return rewriteValueARM64_OpGeq8_0(v)
 	case OpGeq8U:
 		return rewriteValueARM64_OpGeq8U_0(v)
+	case OpGetCallerPC:
+		return rewriteValueARM64_OpGetCallerPC_0(v)
 	case OpGetCallerSP:
 		return rewriteValueARM64_OpGetCallerSP_0(v)
 	case OpGetClosurePtr:
@@ -27239,6 +27241,15 @@ func rewriteValueARM64_OpGeq8U_0(v *Value) bool {
 		return true
 	}
 }
+func rewriteValueARM64_OpGetCallerPC_0(v *Value) bool {
+	// match: (GetCallerPC)
+	// cond:
+	// result: (LoweredGetCallerPC)
+	for {
+		v.reset(OpARM64LoweredGetCallerPC)
+		return true
+	}
+}
 func rewriteValueARM64_OpGetCallerSP_0(v *Value) bool {
 	// match: (GetCallerSP)
 	// cond:

src/cmd/internal/obj/arm64/obj7.go

@@ -821,6 +821,19 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 				}
 			}
 			break
+
+		case obj.AGETCALLERPC:
+			if cursym.Leaf() {
+				/* MOVD LR, Rd */
+				p.As = AMOVD
+				p.From.Type = obj.TYPE_REG
+				p.From.Reg = REGLINK
+			} else {
+				/* MOVD (RSP), Rd */
+				p.As = AMOVD
+				p.From.Type = obj.TYPE_MEM
+				p.From.Reg = REGSP
+			}
 		}
 	}
 }

src/cmd/internal/obj/link.go

@@ -343,6 +343,7 @@ const (
 	ANOP
 	APCDATA
 	ARET
+	AGETCALLERPC
 	ATEXT
 	AUNDEF
 	A_ARCHSPECIFIC

src/cmd/internal/obj/util.go

@@ -493,6 +493,7 @@ var Anames = []string{
 	"NOP",
 	"PCDATA",
 	"RET",
+	"GETCALLERPC",
 	"TEXT",
 	"UNDEF",
 }

src/runtime/asm_arm64.s

@@ -1069,11 +1069,6 @@ TEXT setg_gcc<>(SB),NOSPLIT,$8
 	MOVD	savedR27-8(SP), R27
 	RET
 
-TEXT runtime·getcallerpc(SB),NOSPLIT|NOFRAME,$0-8
-	MOVD	0(RSP), R0		// LR saved by caller
-	MOVD	R0, ret+0(FP)
-	RET
-
 TEXT runtime·abort(SB),NOSPLIT|NOFRAME,$0-0
 	MOVD	ZR, R0
 	MOVD	(R0), R0