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authorRuss Cox <rsc@golang.org>2014-09-29 21:23:52 -0400
committerRuss Cox <rsc@golang.org>2014-09-29 21:23:52 -0400
commitca70c918920b26ae1b88afb7d7a82748677d354f (patch)
tree4ebed7d2383b79533680e43f8e905480f2249e87
parent3fa6b988e0dfc910f3d42d8f12346cfdbb143a69 (diff)
downloadgo-ca70c918920b26ae1b88afb7d7a82748677d354f.tar.gz
go-ca70c918920b26ae1b88afb7d7a82748677d354f.zip
[release-branch.go1.3] runtime: hide cgocallback_gofunc calling cgocallbackg from linker
The linker error at http://build.golang.org/log/42c57ff6b57ab36f6622417108bb5697e4d36fa7 is a false positive: cgocallback_gofunc is invoked on the g0 stack, as explained in its comments, and then it switches to the m->curg stack to invoke cgocallbackg. Checking the stacksplit sequence on the g0 stack doesn't make sense, nor does carrying a check that starts on the g0 stack over to the curg stack. Change the code to use an indirect call so that the linker stacksplit check does not follow through it. LGTM=bradfitz, adg R=golang-codereviews, bradfitz, adg CC=golang-codereviews, iant, r https://golang.org/cl/146510043
-rw-r--r--src/pkg/runtime/asm_amd64.s3
1 files changed, 2 insertions, 1 deletions
diff --git a/src/pkg/runtime/asm_amd64.s b/src/pkg/runtime/asm_amd64.s
index 3c7eaf3433..2e28866098 100644
--- a/src/pkg/runtime/asm_amd64.s
+++ b/src/pkg/runtime/asm_amd64.s
@@ -784,7 +784,8 @@ havem:
MOVQ BP, -8(DI)
LEAQ -(8+8)(DI), SP
MOVQ R8, 0(SP)
- CALL runtime·cgocallbackg(SB)
+ MOVQ $runtime·cgocallbackg(SB), AX // hide function call from linker
+ CALL AX
MOVQ 0(SP), R8
// Restore g->sched (== m->curg->sched) from saved values.