[llvm] [NFC] [HWASan] make getAndroidSlotPtr function generic (PR #86200)

[Florian Mayer via llvm-commits]

https://github.com/fmayer created https://github.com/llvm/llvm-project/pull/86200

This is so we can use a different slot for stack MTE.


>From b62863446352c8e0b92d1ee660dfa2dbcfcc9439 Mon Sep 17 00:00:00 2001
From: Florian Mayer <fmayer at google.com>
Date: Thu, 21 Mar 2024 14:37:52 -0700
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
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Created using spr 1.3.4
---
 llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h  | 2 +-
 llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp | 5 ++++-
 llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp         | 4 ++--
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h b/llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h
index 158c358a9e4618..fb3ab33a0629da 100644
--- a/llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h
+++ b/llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h
@@ -84,7 +84,7 @@ bool isLifetimeIntrinsic(Value *V);
 Value *readRegister(IRBuilder<> &IRB, StringRef Name);
 Value *getFP(IRBuilder<> &IRB);
 Value *getPC(const Triple &TargetTriple, IRBuilder<> &IRB);
-Value *getAndroidSanitizerSlotPtr(IRBuilder<> &IRB);
+Value *getAndroidSlotPtr(IRBuilder<> &IRB, int Slot);
 
 } // namespace memtag
 } // namespace llvm
diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index 3c95610fa3e80b..3b0d99abd0cd0c 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -1220,8 +1220,11 @@ Value *HWAddressSanitizer::untagPointer(IRBuilder<> &IRB, Value *PtrLong) {
 }
 
 Value *HWAddressSanitizer::getHwasanThreadSlotPtr(IRBuilder<> &IRB) {
+  // Android provides a fixed TLS slot for sanitizers. See TLS_SLOT_SANITIZER
+  // in Bionic's libc/platform/bionic/tls_defines.h.
+  constexpr int SanitizerSlot = 6;
   if (TargetTriple.isAArch64() && TargetTriple.isAndroid())
-    return memtag::getAndroidSanitizerSlotPtr(IRB);
+    return memtag::getAndroidSlotPtr(IRB, SanitizerSlot);
   return ThreadPtrGlobal;
 }
 
diff --git a/llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp b/llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp
index fd94a120bc6655..7b1eb70168d894 100644
--- a/llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp
+++ b/llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp
@@ -273,14 +273,14 @@ Value *getFP(IRBuilder<> &IRB) {
       IRB.getIntPtrTy(M->getDataLayout()));
 }
 
-Value *getAndroidSanitizerSlotPtr(IRBuilder<> &IRB) {
+Value *getAndroidSlotPtr(IRBuilder<> &IRB, int Slot) {
   Module *M = IRB.GetInsertBlock()->getParent()->getParent();
   // Android provides a fixed TLS slot for sanitizers. See TLS_SLOT_SANITIZER
   // in Bionic's libc/private/bionic_tls.h.
   Function *ThreadPointerFunc =
       Intrinsic::getDeclaration(M, Intrinsic::thread_pointer);
   return IRB.CreateConstGEP1_32(IRB.getInt8Ty(),
-                                IRB.CreateCall(ThreadPointerFunc), 0x30);
+                                IRB.CreateCall(ThreadPointerFunc), 8 * Slot);
 }
 
 } // namespace memtag