[HWASan] [NFC] pull logic to get sanitizer ptr out of hwasan (#86024)

Also some drive by cleanup removing an unnnecessary argument and a
redundant condition.

Author: fmayer

llvm/include/llvm/Transforms/Utils/MemoryTaggingSupport.h

@@ -84,6 +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);
 
 } // namespace memtag
 } // namespace llvm

llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp

@@ -363,7 +363,7 @@ class HWAddressSanitizer {
   Value *getAllocaTag(IRBuilder<> &IRB, Value *StackTag, unsigned AllocaNo);
   Value *getUARTag(IRBuilder<> &IRB);
 
-  Value *getHwasanThreadSlotPtr(IRBuilder<> &IRB, Type *Ty);
+  Value *getHwasanThreadSlotPtr(IRBuilder<> &IRB);
   Value *applyTagMask(IRBuilder<> &IRB, Value *OldTag);
   unsigned retagMask(unsigned AllocaNo);
 
@@ -1219,20 +1219,10 @@ Value *HWAddressSanitizer::untagPointer(IRBuilder<> &IRB, Value *PtrLong) {
   return UntaggedPtrLong;
 }
 
-Value *HWAddressSanitizer::getHwasanThreadSlotPtr(IRBuilder<> &IRB, Type *Ty) {
-  Module *M = IRB.GetInsertBlock()->getParent()->getParent();
-  if (TargetTriple.isAArch64() && TargetTriple.isAndroid()) {
-    // 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(Int8Ty, IRB.CreateCall(ThreadPointerFunc),
-                                  0x30);
-  }
-  if (ThreadPtrGlobal)
-    return ThreadPtrGlobal;
-
-  return nullptr;
+Value *HWAddressSanitizer::getHwasanThreadSlotPtr(IRBuilder<> &IRB) {
+  if (TargetTriple.isAArch64() && TargetTriple.isAndroid())
+    return memtag::getAndroidSanitizerSlotPtr(IRB);
+  return ThreadPtrGlobal;
 }
 
 Value *HWAddressSanitizer::getCachedFP(IRBuilder<> &IRB) {
@@ -1271,7 +1261,7 @@ void HWAddressSanitizer::emitPrologue(IRBuilder<> &IRB, bool WithFrameRecord) {
 
   auto getThreadLongMaybeUntagged = [&]() {
     if (!SlotPtr)
-      SlotPtr = getHwasanThreadSlotPtr(IRB, IntptrTy);
+      SlotPtr = getHwasanThreadSlotPtr(IRB);
     if (!ThreadLong)
       ThreadLong = IRB.CreateLoad(IntptrTy, SlotPtr);
     // Extract the address field from ThreadLong. Unnecessary on AArch64 with

llvm/lib/Transforms/Utils/MemoryTaggingSupport.cpp

@@ -273,5 +273,15 @@ Value *getFP(IRBuilder<> &IRB) {
       IRB.getIntPtrTy(M->getDataLayout()));
 }
 
+Value *getAndroidSanitizerSlotPtr(IRBuilder<> &IRB) {
+  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);
+}
+
 } // namespace memtag
 } // namespace llvm