From 053a1f232023b15c21bdd8e89f67de21d8aea285 Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Tue, 29 Jan 2019 00:49:23 +0000 Subject: [PATCH] runtime: use the call instruction's PC for panic-in-runtime detection If a panic happens in the runtime we turn that into a fatal error. We use the caller's PC to determine if the panic call is inside the runtime. getcallerpc returns the PC immediately after the call instruction. If the call is the very last instruction of a function, it may not find this PC belong to a runtime function, giving false result. We need to back off the PC by 1 to the call instruction. The gc runtime doesn't do this because the gc compiler always emit an instruction following a panic call, presumably an UNDEF instruction which turns into an architecture-specific illegal instruction. Our compiler doesn't do this. Reviewed-on: https://go-review.googlesource.com/c/159437 From-SVN: r268358 --- gcc/go/gofrontend/MERGE | 2 +- libgo/go/runtime/panic.go | 4 ++-- libgo/runtime/go-runtime-error.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE index 4bdcf96..0eff5eb 100644 --- a/gcc/go/gofrontend/MERGE +++ b/gcc/go/gofrontend/MERGE @@ -1,4 +1,4 @@ -5ccb2d8593963e06ec3a35d362b384e82301d9f0 +c2cac0ba0a92e74d5675c3c9f4e53d2567dbc903 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/panic.go b/libgo/go/runtime/panic.go index bfd2f2d..9b8ffb9 100644 --- a/libgo/go/runtime/panic.go +++ b/libgo/go/runtime/panic.go @@ -53,7 +53,7 @@ var indexError = error(errorString("index out of range")) // entire runtime stack for easier debugging. func panicindex() { - name, _, _ := funcfileline(getcallerpc(), -1) + name, _, _ := funcfileline(getcallerpc()-1, -1) if hasPrefix(name, "runtime.") { throw(string(indexError.(errorString))) } @@ -64,7 +64,7 @@ func panicindex() { var sliceError = error(errorString("slice bounds out of range")) func panicslice() { - name, _, _ := funcfileline(getcallerpc(), -1) + name, _, _ := funcfileline(getcallerpc()-1, -1) if hasPrefix(name, "runtime.") { throw(string(sliceError.(errorString))) } diff --git a/libgo/runtime/go-runtime-error.c b/libgo/runtime/go-runtime-error.c index f1c1650..5db3555 100644 --- a/libgo/runtime/go-runtime-error.c +++ b/libgo/runtime/go-runtime-error.c @@ -63,7 +63,7 @@ __go_runtime_error (int32 i) struct funcfileline_return fileline; bool in_runtime; - fileline = runtime_funcfileline ((uintptr) runtime_getcallerpc(), 0); + fileline = runtime_funcfileline ((uintptr) runtime_getcallerpc()-1, 0); in_runtime = (fileline.retfn.len > 0 && (__builtin_strncmp ((const char *) fileline.retfn.str, "runtime.", 8) -- 2.7.4