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author | Ryan Govostes <rzg@apple.com> | 2016-05-05 01:14:39 +0000 |
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committer | Ryan Govostes <rzg@apple.com> | 2016-05-05 01:14:39 +0000 |
commit | 097c5b051cf40a55dab1edaba5a24606033a4f63 (patch) | |
tree | 9596728f9af66be5eda9a2dc5fe3815662324b99 | |
parent | 6739a10cec3d5681cc1c0f793be58756dfe0537a (diff) | |
download | bcm5719-llvm-097c5b051cf40a55dab1edaba5a24606033a4f63.tar.gz bcm5719-llvm-097c5b051cf40a55dab1edaba5a24606033a4f63.zip |
[asan] add option to set shadow mapping offset
Allowing overriding the default ASAN shadow mapping offset with the
-asan-shadow-offset option, and allow zero to be specified for both offset and
scale.
llvm-svn: 268586
-rw-r--r-- | llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp | 11 | ||||
-rw-r--r-- | llvm/test/Instrumentation/AddressSanitizer/scale-offset.ll | 39 |
2 files changed, 48 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp index f2b5179b436..7648352d0b9 100644 --- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp +++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp @@ -204,10 +204,13 @@ static cl::opt<bool> ClSkipPromotableAllocas( // These flags allow to change the shadow mapping. // The shadow mapping looks like -// Shadow = (Mem >> scale) + (1 << offset_log) +// Shadow = (Mem >> scale) + offset static cl::opt<int> ClMappingScale("asan-mapping-scale", cl::desc("scale of asan shadow mapping"), cl::Hidden, cl::init(0)); +static cl::opt<uint64_t> ClMappingOffset("asan-mapping-offset", + cl::desc("offset of asan shadow mapping [EXPERIMENTAL]"), + cl::Hidden, cl::init(0)); // Optimization flags. Not user visible, used mostly for testing // and benchmarking the tool. @@ -404,10 +407,14 @@ static ShadowMapping getShadowMapping(Triple &TargetTriple, int LongSize, } Mapping.Scale = kDefaultShadowScale; - if (ClMappingScale) { + if (ClMappingScale.getNumOccurrences() > 0) { Mapping.Scale = ClMappingScale; } + if (ClMappingOffset.getNumOccurrences() > 0) { + Mapping.Offset = ClMappingOffset; + } + // OR-ing shadow offset if more efficient (at least on x86) if the offset // is a power of two, but on ppc64 we have to use add since the shadow // offset is not necessary 1/8-th of the address space. On SystemZ, diff --git a/llvm/test/Instrumentation/AddressSanitizer/scale-offset.ll b/llvm/test/Instrumentation/AddressSanitizer/scale-offset.ll new file mode 100644 index 00000000000..8345586fec4 --- /dev/null +++ b/llvm/test/Instrumentation/AddressSanitizer/scale-offset.ll @@ -0,0 +1,39 @@ +; Test that the scale (-asan-mapping-scale) and offset (-asan-mapping-offset) command-line options work as expected +; +; RUN: opt < %s -asan -asan-module -asan-mapping-offset 0xdeadbeef -S | FileCheck --check-prefix=CHECK-OFFSET %s +; RUN: opt < %s -asan -asan-module -asan-mapping-scale 1 -S | FileCheck --check-prefix=CHECK-SCALE %s +; RUN: opt < %s -asan -asan-module -asan-mapping-offset 0xc0ffee -asan-mapping-scale 0 -S | FileCheck --check-prefix=CHECK-BOTH %s +target triple = "x86_64-unknown-linux-gnu" + +define i32 @read_offset(i32* %a) sanitize_address { +entry: + %tmp1 = load i32, i32* %a, align 4 + ret i32 %tmp1 +} +; CHECK-OFFSET-LABEL: @read_offset +; CHECK-OFFSET-NOT: ret +; CHECK-OFFSET: lshr {{.*}} 3 +; CHECK-OFFSET-NEXT: add{{.*}}3735928559 +; CHECK-OFFSET: ret + +define i32 @read_scale(i32* %a) sanitize_address { +entry: + %tmp1 = load i32, i32* %a, align 4 + ret i32 %tmp1 +} +; CHECK-SCALE-LABEL: @read_scale +; CHECK-SCALE-NOT: ret +; CHECK-SCALE: lshr {{.*}} 1 +; CHECK-SCALE-NEXT: add{{.*}} +; CHECK-SCALE: ret + +define i32 @read_both(i32* %a) sanitize_address { +entry: + %tmp1 = load i32, i32* %a, align 4 + ret i32 %tmp1 +} +; CHECK-BOTH-LABEL: @read_both +; CHECK-BOTH-NOT: ret +; CHECK-BOTH: lshr {{.*}} 0 +; CHECK-BOTH-NEXT: add{{.*}}12648430 +; CHECK-BOTH: ret |