[llvm] [llvm] Implement address sanitizer on AIX (2/3) (PR #129926)
Jake Egan via llvm-commits
llvm-commits at lists.llvm.org
Sat Mar 8 20:52:23 PST 2025
https://github.com/jakeegan updated https://github.com/llvm/llvm-project/pull/129926
>From a6a50e70e7a62ebe032c660f6f85272f1a11d79e Mon Sep 17 00:00:00 2001
From: Jake Egan <jake.egan at ibm.com>
Date: Sat, 8 Mar 2025 23:14:25 -0500
Subject: [PATCH 1/2] [llvm] Implement address sanitizer on AIX (2/3)
---
.../Instrumentation/AddressSanitizer.cpp | 26 ++++++++++++++++---
.../AddressSanitizer/mapping-aix.ll | 21 +++++++++++++++
2 files changed, 44 insertions(+), 3 deletions(-)
create mode 100644 llvm/test/Instrumentation/AddressSanitizer/mapping-aix.ll
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index bbe7040121649..9e89d8cbab759 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -119,6 +119,9 @@ static const uint64_t kNetBSDKasan_ShadowOffset64 = 0xdfff900000000000;
static const uint64_t kPS_ShadowOffset64 = 1ULL << 40;
static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
static const uint64_t kEmscriptenShadowOffset = 0;
+static const uint64_t kAIXShadowOffset32 = 0x40000000;
+// 64-BIT AIX is not yet ready.
+static const uint64_t kAIXShadowOffset64 = 0x0a01000000000000ULL;
// The shadow memory space is dynamically allocated.
static const uint64_t kWindowsShadowOffset64 = kDynamicShadowSentinel;
@@ -128,6 +131,8 @@ static const size_t kMaxStackMallocSize = 1 << 16; // 64K
static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
+static const uint32_t kAIXHighBits = 6;
+
const char kAsanModuleCtorName[] = "asan.module_ctor";
const char kAsanModuleDtorName[] = "asan.module_dtor";
static const uint64_t kAsanCtorAndDtorPriority = 1;
@@ -463,11 +468,14 @@ namespace {
/// This struct defines the shadow mapping using the rule:
/// shadow = (mem >> Scale) ADD-or-OR Offset.
+/// However, on 64-bit AIX, we use HighBits to reduce the mapped address space:
+/// shadow = ((mem << HighBits) >> (HighBits + Scale)) + Offset
/// If InGlobal is true, then
/// extern char __asan_shadow[];
/// shadow = (mem >> Scale) + &__asan_shadow
struct ShadowMapping {
int Scale;
+ int HighBits;
uint64_t Offset;
bool OrShadowOffset;
bool InGlobal;
@@ -487,6 +495,7 @@ static ShadowMapping getShadowMapping(const Triple &TargetTriple, int LongSize,
bool IsLinux = TargetTriple.isOSLinux();
bool IsPPC64 = TargetTriple.getArch() == Triple::ppc64 ||
TargetTriple.getArch() == Triple::ppc64le;
+ bool IsAIX = TargetTriple.isOSAIX();
bool IsSystemZ = TargetTriple.getArch() == Triple::systemz;
bool IsX86_64 = TargetTriple.getArch() == Triple::x86_64;
bool IsMIPSN32ABI = TargetTriple.isABIN32();
@@ -526,6 +535,8 @@ static ShadowMapping getShadowMapping(const Triple &TargetTriple, int LongSize,
Mapping.Offset = kWindowsShadowOffset32;
else if (IsEmscripten)
Mapping.Offset = kEmscriptenShadowOffset;
+ else if (IsAIX)
+ Mapping.Offset = kAIXShadowOffset32;
else
Mapping.Offset = kDefaultShadowOffset32;
} else { // LongSize == 64
@@ -533,7 +544,9 @@ static ShadowMapping getShadowMapping(const Triple &TargetTriple, int LongSize,
// space is always available.
if (IsFuchsia)
Mapping.Offset = 0;
- else if (IsPPC64)
+ else if (IsAIX)
+ Mapping.Offset = kAIXShadowOffset64;
+ else if (IsPPC64 && !IsAIX)
Mapping.Offset = kPPC64_ShadowOffset64;
else if (IsSystemZ)
Mapping.Offset = kSystemZ_ShadowOffset64;
@@ -592,13 +605,16 @@ static ShadowMapping getShadowMapping(const Triple &TargetTriple, int LongSize,
// SystemZ, we could OR the constant in a single instruction, but it's more
// efficient to load it once and use indexed addressing.
Mapping.OrShadowOffset = !IsAArch64 && !IsPPC64 && !IsSystemZ && !IsPS &&
- !IsRISCV64 && !IsLoongArch64 &&
+ !IsRISCV64 && !IsLoongArch64 && !IsAIX &&
!(Mapping.Offset & (Mapping.Offset - 1)) &&
Mapping.Offset != kDynamicShadowSentinel;
bool IsAndroidWithIfuncSupport =
IsAndroid && !TargetTriple.isAndroidVersionLT(21);
Mapping.InGlobal = ClWithIfunc && IsAndroidWithIfuncSupport && IsArmOrThumb;
+ if (IsAIX && LongSize == 64)
+ Mapping.HighBits = kAIXHighBits;
+
return Mapping;
}
@@ -1326,7 +1342,11 @@ static bool isUnsupportedAMDGPUAddrspace(Value *Addr) {
Value *AddressSanitizer::memToShadow(Value *Shadow, IRBuilder<> &IRB) {
// Shadow >> scale
- Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
+ if (TargetTriple.isOSAIX() && TargetTriple.getArch() == Triple::ppc64)
+ Shadow = IRB.CreateLShr(IRB.CreateShl(Shadow, Mapping.HighBits),
+ Mapping.Scale + Mapping.HighBits);
+ else
+ Shadow = IRB.CreateLShr(Shadow, Mapping.Scale);
if (Mapping.Offset == 0) return Shadow;
// (Shadow >> scale) | offset
Value *ShadowBase;
diff --git a/llvm/test/Instrumentation/AddressSanitizer/mapping-aix.ll b/llvm/test/Instrumentation/AddressSanitizer/mapping-aix.ll
new file mode 100644
index 0000000000000..267ea605e6755
--- /dev/null
+++ b/llvm/test/Instrumentation/AddressSanitizer/mapping-aix.ll
@@ -0,0 +1,21 @@
+; Test shadow memory mapping on AIX
+
+; RUN: opt -passes=asan -mtriple=powerpc64-ibm-aix -S < %s | FileCheck %s -check-prefix=CHECK-64
+; RUN: opt -passes=asan -mtriple=powerpc-ibm-aix -S < %s | FileCheck %s -check-prefix=CHECK-32
+
+; CHECK: @test
+; On 64-bit AIX, we expect a left shift of 6 (HIGH_BITS) followed by a right shift of 9 (HIGH_BITS
+; + ASAN_SHADOW_SCALE) and an offset of 0x0a01000000000000.
+; CHECK-64: shl {{.*}} 6
+; CHECK-64-NEXT: lshr {{.*}} 9
+; CHECK-64-NEXT: add {{.*}} 720857415355990016
+; On 32-bit AIX, we expect just a right shift of 3 and an offset of 0x40000000.
+; CHECK-32: lshr {{.*}} 3
+; CHECK-32-NEXT: add {{.*}} 1073741824
+; CHECK: ret
+
+define i32 @test(i32* %a) sanitize_address {
+entry:
+ %tmp1 = load i32, i32* %a, align 4
+ ret i32 %tmp1
+}
>From c68a40b1ffb5da828c60dad144a61c8a6190890b Mon Sep 17 00:00:00 2001
From: Jake Egan <jake.egan at ibm.com>
Date: Sat, 8 Mar 2025 23:52:06 -0500
Subject: [PATCH 2/2] Fix formatting
---
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 9e89d8cbab759..7e07728d3d1bd 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -536,7 +536,7 @@ static ShadowMapping getShadowMapping(const Triple &TargetTriple, int LongSize,
else if (IsEmscripten)
Mapping.Offset = kEmscriptenShadowOffset;
else if (IsAIX)
- Mapping.Offset = kAIXShadowOffset32;
+ Mapping.Offset = kAIXShadowOffset32;
else
Mapping.Offset = kDefaultShadowOffset32;
} else { // LongSize == 64
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