runtime: make PCDATA_RegMapUnsafe more clear and remove magic number
Change-Id: Ibf3ee755c3fbec03a9396840dc92ce148c49d9f7
GitHub-Last-Rev: 945d8aaa136003dc381c6aa48bff9ea7ca2c6991
GitHub-Pull-Request: golang/go#41262
Reviewed-on: https://go-review.googlesource.com/c/go/+/253377
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/cmd/internal/objabi/funcdata.go b/src/cmd/internal/objabi/funcdata.go
index d5bacb5..c9480bf 100644
--- a/src/cmd/internal/objabi/funcdata.go
+++ b/src/cmd/internal/objabi/funcdata.go
@@ -35,7 +35,7 @@
// PCDATA_RegMapIndex values.
//
// Only if !go115ReduceLiveness.
- PCDATA_RegMapUnsafe = -2 // Unsafe for async preemption
+ PCDATA_RegMapUnsafe = PCDATA_UnsafePointUnsafe // Unsafe for async preemption
// PCDATA_UnsafePoint values.
PCDATA_UnsafePointSafe = -1 // Safe for async preemption
diff --git a/src/runtime/debugcall.go b/src/runtime/debugcall.go
index 6c285ec..b5480c7 100644
--- a/src/runtime/debugcall.go
+++ b/src/runtime/debugcall.go
@@ -87,7 +87,7 @@
pcdata = 0 // in prologue
}
stkmap := (*stackmap)(funcdata(f, _FUNCDATA_RegPointerMaps))
- if pcdata == -2 || stkmap == nil {
+ if pcdata == _PCDATA_RegMapUnsafe || stkmap == nil {
// Not at a safe point.
ret = debugCallUnsafePoint
return
diff --git a/src/runtime/preempt.go b/src/runtime/preempt.go
index 7618565..17ef2c9 100644
--- a/src/runtime/preempt.go
+++ b/src/runtime/preempt.go
@@ -406,7 +406,7 @@
var startpc uintptr
if !go115ReduceLiveness {
smi := pcdatavalue(f, _PCDATA_RegMapIndex, pc, nil)
- if smi == -2 {
+ if smi == _PCDATA_RegMapUnsafe {
// Unsafe-point marked by compiler. This includes
// atomic sequences (e.g., write barrier) and nosplit
// functions (except at calls).
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go
index ddb5ea8..fa8d170 100644
--- a/src/runtime/symtab.go
+++ b/src/runtime/symtab.go
@@ -284,6 +284,9 @@
)
const (
+ // Only if !go115ReduceLiveness.
+ _PCDATA_RegMapUnsafe = _PCDATA_UnsafePointUnsafe // Unsafe for async preemption
+
// PCDATA_UnsafePoint values.
_PCDATA_UnsafePointSafe = -1 // Safe for async preemption
_PCDATA_UnsafePointUnsafe = -2 // Unsafe for async preemption
