runtime: fix sigprof frame counting

    If sigtramp and sigtrampgo are both on stack, n -= framesToDiscard
    is executed twice, which should actually run only once.

    Reviewed-on: https://go-review.googlesource.com/c/159238

From-SVN: r268366

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index 0eff5eb..10e20ce 100644 (file)
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-c2cac0ba0a92e74d5675c3c9f4e53d2567dbc903
+5af8ee0693944c280b1f529450dbfd4ec1ee451d
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

diff --git a/libgo/go/runtime/proc.go b/libgo/go/runtime/proc.go
index 05dd53d..b4fa88f 100644 (file)
--- a/libgo/go/runtime/proc.go
+++ b/libgo/go/runtime/proc.go
@@ -3542,14 +3542,13 @@ func sigprof(pc uintptr, gp *g, mp *m) {
                for i := 0; i < n; i++ {
                        if stklocs[i].function == "runtime.sigtrampgo" && i+2 < n {
                                framesToDiscard = i + 2
-                               n -= framesToDiscard
                        }
                        if stklocs[i].function == "runtime.sigtramp" && i+2 < n {
                                framesToDiscard = i + 2
-                               n -= framesToDiscard
                                break
                        }
                }
+               n -= framesToDiscard
                for i := 0; i < n; i++ {
                        stk[i] = stklocs[i+framesToDiscard].pc
                }