[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;
+ }
}
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/with-ifunc.ll b/llvm/test/Instrumentation/HWAddressSanitizer/with-ifunc.ll
new file mode 100644
index 0000000..2f4abb4
--- /dev/null
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/with-ifunc.ll
@@ -0,0 +1,30 @@
+; Test -hwasan-with-ifunc flag.
+;
+; RUN: opt -hwasan -S < %s | \
+; RUN: FileCheck %s --check-prefixes=CHECK,CHECK-IFUNC
+; RUN: opt -hwasan -S -hwasan-with-ifunc=0 < %s | \
+; RUN: FileCheck %s --check-prefixes=CHECK,CHECK-NOIFUNC
+; RUN: opt -hwasan -S -hwasan-with-ifunc=1 < %s | \
+; RUN: FileCheck %s --check-prefixes=CHECK,CHECK-IFUNC
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64--linux-android22"
+
+; CHECK-IFUNC: @__hwasan_shadow = external global [0 x i8]
+; CHECK-NOIFUNC: @__hwasan_shadow_memory_dynamic_address = external global i64
+
+define i32 @test_load(i32* %a) sanitize_hwaddress {
+; First instrumentation in the function must be to load the dynamic shadow
+; address into a local variable.
+; CHECK-LABEL: @test_load
+; CHECK: entry:
+
+; CHECK-IFUNC: %[[A:[^ ]*]] = call i64 asm "", "=r,0"([0 x i8]* @__hwasan_shadow)
+; CHECK-IFUNC: add i64 %{{.*}}, %[[A]]
+
+; CHECK-NOIFUNC: load i64, i64* @__hwasan_shadow_memory_dynamic_address
+
+entry:
+ %x = load i32, i32* %a, align 4
+ ret i32 %x
+}