From 37a5ffaca0ddf95a56da0deead8e01aa943a0aaf Mon Sep 17 00:00:00 2001 From: Kuba Brecka Date: Fri, 17 Jul 2015 06:29:57 +0000 Subject: [asan] Fix invalid debug info for promotable allocas Since r230724 ("Skip promotable allocas to improve performance at -O0"), there is a regression in the generated debug info for those non-instrumented variables. When inspecting such a variable's value in LLDB, you often get garbage instead of the actual value. ASan instrumentation is inserted before the creation of the non-instrumented alloca. The only allocas that are considered standard stack variables are the ones declared in the first basic-block, but the initial instrumentation setup in the function breaks that invariant. This patch makes sure uninstrumented allocas stay in the first BB. Differential Revision: http://reviews.llvm.org/D11179 llvm-svn: 242510 --- .../debug_info_noninstrumented_alloca.ll | 26 ++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 llvm/test/Instrumentation/AddressSanitizer/debug_info_noninstrumented_alloca.ll (limited to 'llvm/test') diff --git a/llvm/test/Instrumentation/AddressSanitizer/debug_info_noninstrumented_alloca.ll b/llvm/test/Instrumentation/AddressSanitizer/debug_info_noninstrumented_alloca.ll new file mode 100644 index 00000000000..7c38729ff43 --- /dev/null +++ b/llvm/test/Instrumentation/AddressSanitizer/debug_info_noninstrumented_alloca.ll @@ -0,0 +1,26 @@ +; This test checks that non-instrumented allocas stay in the first basic block. +; Only first-basic-block allocas are considered stack slots, and moving them +; breaks debug info. + +; RUN: opt < %s -asan -asan-module -S | FileCheck %s + +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.10.0" + +define i32 @foo() sanitize_address { +entry: + ; Regular alloca, will get instrumented (forced by the ptrtoint below). + %instrumented = alloca i32, align 4 + + ; Won't be instrumented because of asan-skip-promotable-allocas. + %non_instrumented = alloca i32, align 4 + store i32 0, i32* %non_instrumented, align 4 + %value = load i32, i32* %non_instrumented, align 4 + + %ptr = ptrtoint i32* %instrumented to i64 + ret i32 %value +} + +; CHECK: entry: +; CHECK: %non_instrumented = alloca i32, align 4 +; CHECK: load i32, i32* @__asan_option_detect_stack_use_after_return -- cgit v1.2.3