[hwasan] Add -hwasan-with-ifunc flag.
Summary: Similar to asan's flag, it can be used to disable the use of ifunc to access hwasan shadow address.
Reviewers: vitalybuka, kcc
Subscribers: srhines, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D50544
llvm-svn: 339447
diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index d62598b..bc690cc 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -127,6 +127,11 @@
cl::desc("HWASan shadow mapping offset [EXPERIMENTAL]"), cl::Hidden,
cl::init(0));
+static cl::opt<bool>
+ ClWithIfunc("hwasan-with-ifunc",
+ cl::desc("Access dynamic shadow through an ifunc global on "
+ "platforms that support this"),
+ cl::Hidden, cl::init(false));
namespace {
/// An instrumentation pass implementing detection of addressability bugs
@@ -751,13 +756,21 @@
IsAndroid && !TargetTriple.isAndroidVersionLT(21);
Scale = kDefaultShadowScale;
+ const bool WithIfunc = ClWithIfunc.getNumOccurrences() > 0
+ ? ClWithIfunc
+ : IsAndroidWithIfuncSupport;
- if (ClEnableKhwasan || ClInstrumentWithCalls || !IsAndroidWithIfuncSupport)
- Offset = 0;
- else
- Offset = kDynamicShadowSentinel;
- if (ClMappingOffset.getNumOccurrences() > 0)
+ if (ClMappingOffset.getNumOccurrences() > 0) {
+ InGlobal = false;
Offset = ClMappingOffset;
-
- InGlobal = IsAndroidWithIfuncSupport;
+ } else if (ClEnableKhwasan || ClInstrumentWithCalls) {
+ InGlobal = false;
+ Offset = 0;
+ } else if (WithIfunc) {
+ InGlobal = true;
+ Offset = kDynamicShadowSentinel;
+ } else {
+ InGlobal = false;
+ Offset = kDynamicShadowSentinel;
+ }
}