[release-branch.go1.16] cmd/compile: correct type of pointer difference on RISCV64
Pointer comparison is lowered to the following on RISCV64
(EqPtr x y) => (SEQZ (SUB <x.Type> x y))
The difference of two pointers (the SUB) should not be pointer
type. Otherwise it can cause the GC to find a bad pointer.
Updates #51101.
Fixes #51198.
Change-Id: I7e73c2155c36ff403c032981a9aa9cccbfdf0f64
Reviewed-on: https://go-review.googlesource.com/c/go/+/385655
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
(cherry picked from commit 1ed30ca537a05b887f8479027b6363a03f957610)
Reviewed-on: https://go-review.googlesource.com/c/go/+/386475
diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
index 4380a5e..1d3e738 100644
--- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules
+++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
@@ -249,7 +249,7 @@
(Leq64F ...) => (FLED ...)
(Leq32F ...) => (FLES ...)
-(EqPtr x y) => (SEQZ (SUB <x.Type> x y))
+(EqPtr x y) => (SEQZ (SUB <typ.Uintptr> x y))
(Eq64 x y) => (SEQZ (SUB <x.Type> x y))
(Eq32 x y) => (SEQZ (SUBW <x.Type> x y))
(Eq16 x y) => (SEQZ (SUB <x.Type> (ZeroExt16to64 x) (ZeroExt16to64 y)))
@@ -257,7 +257,7 @@
(Eq64F ...) => (FEQD ...)
(Eq32F ...) => (FEQS ...)
-(NeqPtr x y) => (SNEZ (SUB <x.Type> x y))
+(NeqPtr x y) => (SNEZ (SUB <typ.Uintptr> x y))
(Neq64 x y) => (SNEZ (SUB <x.Type> x y))
(Neq32 x y) => (SNEZ (SUBW <x.Type> x y))
(Neq16 x y) => (SNEZ (SUB <x.Type> (ZeroExt16to64 x) (ZeroExt16to64 y)))
diff --git a/src/cmd/compile/internal/ssa/rewriteRISCV64.go b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
index fb507b6..a34b59d 100644
--- a/src/cmd/compile/internal/ssa/rewriteRISCV64.go
+++ b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
@@ -960,13 +960,14 @@
v_1 := v.Args[1]
v_0 := v.Args[0]
b := v.Block
+ typ := &b.Func.Config.Types
// match: (EqPtr x y)
- // result: (SEQZ (SUB <x.Type> x y))
+ // result: (SEQZ (SUB <typ.Uintptr> x y))
for {
x := v_0
y := v_1
v.reset(OpRISCV64SEQZ)
- v0 := b.NewValue0(v.Pos, OpRISCV64SUB, x.Type)
+ v0 := b.NewValue0(v.Pos, OpRISCV64SUB, typ.Uintptr)
v0.AddArg2(x, y)
v.AddArg(v0)
return true
@@ -2519,13 +2520,14 @@
v_1 := v.Args[1]
v_0 := v.Args[0]
b := v.Block
+ typ := &b.Func.Config.Types
// match: (NeqPtr x y)
- // result: (SNEZ (SUB <x.Type> x y))
+ // result: (SNEZ (SUB <typ.Uintptr> x y))
for {
x := v_0
y := v_1
v.reset(OpRISCV64SNEZ)
- v0 := b.NewValue0(v.Pos, OpRISCV64SUB, x.Type)
+ v0 := b.NewValue0(v.Pos, OpRISCV64SUB, typ.Uintptr)
v0.AddArg2(x, y)
v.AddArg(v0)
return true
diff --git a/test/fixedbugs/issue51101.go b/test/fixedbugs/issue51101.go
new file mode 100644
index 0000000..a390e50
--- /dev/null
+++ b/test/fixedbugs/issue51101.go
@@ -0,0 +1,36 @@
+// run
+
+// Copyright 2022 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Issue 51101: on RISCV64, difference of two pointers
+// was marked as pointer and crashes GC.
+
+package main
+
+var a, b int
+
+func main() {
+ F(&b, &a)
+}
+
+//go:noinline
+func F(a, b *int) bool {
+ x := a == b
+ G(x)
+ y := a != b
+ return y
+}
+
+//go:noinline
+func G(bool) {
+ grow([1000]int{20})
+}
+
+func grow(x [1000]int) {
+ if x[0] != 0 {
+ x[0]--
+ grow(x)
+ }
+}
