From: Cherry Zhang <cherryyz@google.com>
Date: Thu, 1 Apr 2021 15:11:04 +0000 (-0400)
Subject: cmd/compile: use ABI0 for cgo_unsafe_args functions
X-Git-Tag: go1.17beta1~880
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=6996bae5d1;p=gostls13.git

cmd/compile: use ABI0 for cgo_unsafe_args functions

cgo_unsafe_args paragma indicates that the function (or its
callee) uses address and offsets to dispatch arguments, which
currently using ABI0 frame layout. Pin them to ABI0.

With this, "GOEXPERIMENT=regabi,regabiargs go run hello.go" works
on Darwin/AMD64.

Change-Id: I3eadd5a3646a9de8fa681fa0a7f46e7cdc217d24
Reviewed-on: https://go-review.googlesource.com/c/go/+/306609
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
---

diff --git a/src/cmd/compile/internal/amd64/ssa.go b/src/cmd/compile/internal/amd64/ssa.go
index 2c767d36d7..8142ba7984 100644
--- a/src/cmd/compile/internal/amd64/ssa.go
+++ b/src/cmd/compile/internal/amd64/ssa.go
@@ -824,10 +824,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.To.Reg = v.Args[0].Reg()
 		ssagen.AddAux2(&p.To, v, sc.Off64())
 	case ssa.OpAMD64MOVOstorezero:
-		if s.ABI != obj.ABIInternal {
-			v.Fatalf("MOVOstorezero can be only used in ABIInternal functions")
-		}
-		if !objabi.Experiment.RegabiG {
+		if !objabi.Experiment.RegabiG || s.ABI != obj.ABIInternal {
 			// zero X15 manually
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 		}
@@ -918,10 +915,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
 	case ssa.OpAMD64DUFFZERO:
-		if s.ABI != obj.ABIInternal {
-			v.Fatalf("MOVOconst can be only used in ABIInternal functions")
-		}
-		if !objabi.Experiment.RegabiG {
+		if !objabi.Experiment.RegabiG || s.ABI != obj.ABIInternal {
 			// zero X15 manually
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 		}
@@ -1004,8 +998,8 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		// Closure pointer is DX.
 		ssagen.CheckLoweredGetClosurePtr(v)
 	case ssa.OpAMD64LoweredGetG:
-		if objabi.Experiment.RegabiG {
-			v.Fatalf("LoweredGetG should not appear in new ABI")
+		if objabi.Experiment.RegabiG && s.ABI == obj.ABIInternal {
+			v.Fatalf("LoweredGetG should not appear in ABIInternal")
 		}
 		r := v.Reg()
 		getgFromTLS(s, r)
diff --git a/src/cmd/compile/internal/ssa/gen/AMD64.rules b/src/cmd/compile/internal/ssa/gen/AMD64.rules
index 98cd865182..839d4a330e 100644
--- a/src/cmd/compile/internal/ssa/gen/AMD64.rules
+++ b/src/cmd/compile/internal/ssa/gen/AMD64.rules
@@ -460,7 +460,7 @@
 (IsInBounds idx len) => (SETB (CMPQ idx len))
 (IsSliceInBounds idx len) => (SETBE (CMPQ idx len))
 (NilCheck ...) => (LoweredNilCheck ...)
-(GetG mem) && !objabi.Experiment.RegabiG => (LoweredGetG mem) // only lower in old ABI. in new ABI we have a G register.
+(GetG mem) && !(objabi.Experiment.RegabiG && v.Block.Func.OwnAux.Fn.ABI() == obj.ABIInternal) => (LoweredGetG mem) // only lower in old ABI. in new ABI we have a G register.
 (GetClosurePtr ...) => (LoweredGetClosurePtr ...)
 (GetCallerPC ...) => (LoweredGetCallerPC ...)
 (GetCallerSP ...) => (LoweredGetCallerSP ...)
diff --git a/src/cmd/compile/internal/ssa/rewriteAMD64.go b/src/cmd/compile/internal/ssa/rewriteAMD64.go
index ce94fdb952..1f56b70816 100644
--- a/src/cmd/compile/internal/ssa/rewriteAMD64.go
+++ b/src/cmd/compile/internal/ssa/rewriteAMD64.go
@@ -4,6 +4,7 @@
 package ssa
 
 import "math"
+import "cmd/internal/obj"
 import "cmd/internal/objabi"
 import "cmd/compile/internal/types"
 
@@ -30465,11 +30466,11 @@ func rewriteValueAMD64_OpFloor(v *Value) bool {
 func rewriteValueAMD64_OpGetG(v *Value) bool {
 	v_0 := v.Args[0]
 	// match: (GetG mem)
-	// cond: !objabi.Experiment.RegabiG
+	// cond: !(objabi.Experiment.RegabiG && v.Block.Func.OwnAux.Fn.ABI() == obj.ABIInternal)
 	// result: (LoweredGetG mem)
 	for {
 		mem := v_0
-		if !(!objabi.Experiment.RegabiG) {
+		if !(!(objabi.Experiment.RegabiG && v.Block.Func.OwnAux.Fn.ABI() == obj.ABIInternal)) {
 			break
 		}
 		v.reset(OpAMD64LoweredGetG)
diff --git a/src/cmd/compile/internal/ssagen/abi.go b/src/cmd/compile/internal/ssagen/abi.go
index 9c203838a5..61d065cea8 100644
--- a/src/cmd/compile/internal/ssagen/abi.go
+++ b/src/cmd/compile/internal/ssagen/abi.go
@@ -146,6 +146,13 @@ func (s *SymABIs) GenABIWrappers() {
 			fn.ABI = defABI
 		}
 
+		if fn.Pragma&ir.CgoUnsafeArgs != 0 {
+			// CgoUnsafeArgs indicates the function (or its callee) uses
+			// offsets to dispatch arguments, which currently using ABI0
+			// frame layout. Pin it to ABI0.
+			fn.ABI = obj.ABI0
+		}
+
 		// Apply references.
 		if abis, ok := s.refs[symName]; ok {
 			fn.ABIRefs |= abis