[release-branch.go1.12] cmd/compile: call ginsnop, not ginsnop2 on ppc64le for mid-stack inlining tracebacks

A recent change to fix stacktraces for inlined functions
introduced a regression on ppc64le when compiling position
independent code. That happened because ginsnop2 was called for
the purpose of inserting a NOP to identify the location of
the inlined function, when ginsnop should have been used.
ginsnop2 is intended to be used before deferreturn to ensure
r2 is properly restored when compiling position independent code.
In some cases the location where r2 is loaded from might not be
initialized. If that happens and r2 is used to generate an address,
the result is likely a SEGV.

This fixes that problem.

Fixes #30283

Change-Id: If70ef27fc65ef31969712422306ac3a57adbd5b6
Reviewed-on: https://go-review.googlesource.com/c/163337
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
(cherry picked from commit 2d3474043cd35ba06d3566df520e8550c479944f)
Reviewed-on: https://go-review.googlesource.com/c/163717
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

11 files changed, 15 insertions, 5 deletions

diff --git a/src/cmd/compile/internal/amd64/galign.go b/src/cmd/compile/internal/amd64/galign.go
index 58c469995f..f6bb961c29 100644
--- a/src/cmd/compile/internal/amd64/galign.go
+++ b/src/cmd/compile/internal/amd64/galign.go
@@ -24,6 +24,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop
 
 	arch.SSAMarkMoves = ssaMarkMoves
 	arch.SSAGenValue = ssaGenValue
diff --git a/src/cmd/compile/internal/arm/galign.go b/src/cmd/compile/internal/arm/galign.go
index 241edaf3a0..8469dbdd73 100644
--- a/src/cmd/compile/internal/arm/galign.go
+++ b/src/cmd/compile/internal/arm/galign.go
@@ -19,6 +19,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop
 
 	arch.SSAMarkMoves = func(s *gc.SSAGenState, b *ssa.Block) {}
 	arch.SSAGenValue = ssaGenValue
diff --git a/src/cmd/compile/internal/arm64/galign.go b/src/cmd/compile/internal/arm64/galign.go
index a64be8e7a6..f01fe8a571 100644
--- a/src/cmd/compile/internal/arm64/galign.go
+++ b/src/cmd/compile/internal/arm64/galign.go
@@ -19,6 +19,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop
 
 	arch.SSAMarkMoves = func(s *gc.SSAGenState, b *ssa.Block) {}
 	arch.SSAGenValue = ssaGenValue
diff --git a/src/cmd/compile/internal/gc/go.go b/src/cmd/compile/internal/gc/go.go
index 376637ba9a..40d01e2d39 100644
--- a/src/cmd/compile/internal/gc/go.go
+++ b/src/cmd/compile/internal/gc/go.go
@@ -255,9 +255,10 @@ type Arch struct {
 	Use387    bool // should 386 backend use 387 FP instructions instead of sse2.
 	SoftFloat bool
 
-	PadFrame  func(int64) int64
-	ZeroRange func(*Progs, *obj.Prog, int64, int64, *uint32) *obj.Prog
-	Ginsnop   func(*Progs) *obj.Prog
+	PadFrame     func(int64) int64
+	ZeroRange    func(*Progs, *obj.Prog, int64, int64, *uint32) *obj.Prog
+	Ginsnop      func(*Progs) *obj.Prog
+	Ginsnopdefer func(*Progs) *obj.Prog // special ginsnop for deferreturn
 
 	// SSAMarkMoves marks any MOVXconst ops that need to avoid clobbering flags.
 	SSAMarkMoves func(*SSAGenState, *ssa.Block)
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index e20137669a..061574dc8a 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -5597,7 +5597,7 @@ func (s *SSAGenState) PrepareCall(v *ssa.Value) {
 		// insert an actual hardware NOP that will have the right line number.
 		// This is different from obj.ANOP, which is a virtual no-op
 		// that doesn't make it into the instruction stream.
-		thearch.Ginsnop(s.pp)
+		thearch.Ginsnopdefer(s.pp)
 	}
 
 	if sym, ok := v.Aux.(*obj.LSym); ok {
diff --git a/src/cmd/compile/internal/mips/galign.go b/src/cmd/compile/internal/mips/galign.go
index f207a17bbf..596dbd7fa0 100644
--- a/src/cmd/compile/internal/mips/galign.go
+++ b/src/cmd/compile/internal/mips/galign.go
@@ -22,6 +22,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop
 	arch.SSAMarkMoves = func(s *gc.SSAGenState, b *ssa.Block) {}
 	arch.SSAGenValue = ssaGenValue
 	arch.SSAGenBlock = ssaGenBlock
diff --git a/src/cmd/compile/internal/mips64/galign.go b/src/cmd/compile/internal/mips64/galign.go
index 5252719e8e..07e9f98be5 100644
--- a/src/cmd/compile/internal/mips64/galign.go
+++ b/src/cmd/compile/internal/mips64/galign.go
@@ -22,6 +22,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop
 
 	arch.SSAMarkMoves = func(s *gc.SSAGenState, b *ssa.Block) {}
 	arch.SSAGenValue = ssaGenValue
diff --git a/src/cmd/compile/internal/ppc64/galign.go b/src/cmd/compile/internal/ppc64/galign.go
index da971d864d..8ad3084410 100644
--- a/src/cmd/compile/internal/ppc64/galign.go
+++ b/src/cmd/compile/internal/ppc64/galign.go
@@ -20,7 +20,8 @@ func Init(arch *gc.Arch) {
 
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
-	arch.Ginsnop = ginsnop2
+	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop2
 
 	arch.SSAMarkMoves = ssaMarkMoves
 	arch.SSAGenValue = ssaGenValue
diff --git a/src/cmd/compile/internal/s390x/galign.go b/src/cmd/compile/internal/s390x/galign.go
index 3f624692bb..26359abe66 100644
--- a/src/cmd/compile/internal/s390x/galign.go
+++ b/src/cmd/compile/internal/s390x/galign.go
@@ -17,6 +17,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop
 
 	arch.SSAMarkMoves = ssaMarkMoves
 	arch.SSAGenValue = ssaGenValue
diff --git a/src/cmd/compile/internal/wasm/ssa.go b/src/cmd/compile/internal/wasm/ssa.go
index 6e6dc557b4..897d6146c5 100644
--- a/src/cmd/compile/internal/wasm/ssa.go
+++ b/src/cmd/compile/internal/wasm/ssa.go
@@ -20,6 +20,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zeroRange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop
 
 	arch.SSAMarkMoves = ssaMarkMoves
 	arch.SSAGenValue = ssaGenValue
diff --git a/src/cmd/compile/internal/x86/galign.go b/src/cmd/compile/internal/x86/galign.go
index 56cc6c637d..7f53ee3731 100644
--- a/src/cmd/compile/internal/x86/galign.go
+++ b/src/cmd/compile/internal/x86/galign.go
@@ -32,6 +32,7 @@ func Init(arch *gc.Arch) {
 	arch.ZeroRange = zerorange
 	arch.ZeroAuto = zeroAuto
 	arch.Ginsnop = ginsnop
+	arch.Ginsnopdefer = ginsnop
 
 	arch.SSAMarkMoves = ssaMarkMoves
 }