SafeStack: Respect alloca addrspace (llvm#112536)

Just insert addrspacecast in cases where the alloca uses a
different address space, since I don't know what else you
could possibly do.

Author: arsenm

llvm/lib/CodeGen/SafeStack.cpp

@@ -192,7 +192,7 @@ class SafeStack {
   SafeStack(Function &F, const TargetLoweringBase &TL, const DataLayout &DL,
             DomTreeUpdater *DTU, ScalarEvolution &SE)
       : F(F), TL(TL), DL(DL), DTU(DTU), SE(SE),
-        StackPtrTy(PointerType::getUnqual(F.getContext())),
+        StackPtrTy(DL.getAllocaPtrType(F.getContext())),
         IntPtrTy(DL.getIntPtrType(F.getContext())),
         Int32Ty(Type::getInt32Ty(F.getContext())) {}
 
@@ -616,7 +616,8 @@ Value *SafeStack::moveStaticAllocasToUnsafeStack(
       IRBuilder<> IRBUser(InsertBefore);
       Value *Off =
           IRBUser.CreatePtrAdd(BasePointer, ConstantInt::get(Int32Ty, -Offset));
-      Value *Replacement = IRBUser.CreateBitCast(Off, AI->getType(), Name);
+      Value *Replacement =
+          IRBUser.CreateAddrSpaceCast(Off, AI->getType(), Name);
 
       if (auto *PHI = dyn_cast<PHINode>(User))
         // PHI nodes may have multiple incoming edges from the same BB (why??),

llvm/lib/CodeGen/TargetLoweringBase.cpp

@@ -1849,7 +1849,8 @@ TargetLoweringBase::getDefaultSafeStackPointerLocation(IRBuilderBase &IRB,
   auto UnsafeStackPtr =
       dyn_cast_or_null<GlobalVariable>(M->getNamedValue(UnsafeStackPtrVar));
 
-  Type *StackPtrTy = PointerType::getUnqual(M->getContext());
+  const DataLayout &DL = M->getDataLayout();
+  PointerType *StackPtrTy = DL.getAllocaPtrType(M->getContext());
 
   if (!UnsafeStackPtr) {
     auto TLSModel = UseTLS ?
@@ -1863,6 +1864,8 @@ TargetLoweringBase::getDefaultSafeStackPointerLocation(IRBuilderBase &IRB,
         UnsafeStackPtrVar, nullptr, TLSModel);
   } else {
     // The variable exists, check its type and attributes.
+    //
+    // FIXME: Move to IR verifier.
     if (UnsafeStackPtr->getValueType() != StackPtrTy)
       report_fatal_error(Twine(UnsafeStackPtrVar) + " must have void* type");
     if (UseTLS != UnsafeStackPtr->isThreadLocal())

llvm/test/Transforms/SafeStack/X86/alloca-addrspace-wrong-addrspace-error.ll

@@ -0,0 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: not --crash opt -passes=safe-stack -mtriple=x86_64-pc-linux-gnu -disable-output %s 2>&1 | FileCheck %s
+
+target datalayout = "A5"
+
+; Declaration of __safestack_unsafe_stack_ptr already exists with wrong address space
+@__safestack_unsafe_stack_ptr = external thread_local(initialexec) global ptr
+
+; CHECK: LLVM ERROR: __safestack_unsafe_stack_ptr must have void* type
+
+define void @alloca_addrspace() nounwind uwtable safestack {
+  %a = alloca i8, align 8, addrspace(5)
+  call void @Capture_as5(ptr addrspace(5) %a)
+  ret void
+}
+
+declare void @Capture_as5(ptr addrspace(5))

llvm/test/Transforms/SafeStack/X86/alloca-addrspace-wrong-addrspace.ll

@@ -0,0 +1,29 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -passes=safe-stack -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s --check-prefix=TLS
+
+target datalayout = "A5"
+
+; Use has wrong address space for the alloca, addrspacecast is inserted.
+define void @correct_alloca_addrspace() nounwind uwtable safestack {
+; TLS-LABEL: define void @correct_alloca_addrspace(
+; TLS-SAME: ) #[[ATTR0:[0-9]+]] !annotation [[META0:![0-9]+]] {
+; TLS-NEXT:  [[ENTRY:.*:]]
+; TLS-NEXT:    [[UNSAFE_STACK_PTR:%.*]] = load ptr addrspace(5), ptr @__safestack_unsafe_stack_ptr, align 8
+; TLS-NEXT:    [[UNSAFE_STACK_STATIC_TOP:%.*]] = getelementptr i8, ptr addrspace(5) [[UNSAFE_STACK_PTR]], i32 -16
+; TLS-NEXT:    store ptr addrspace(5) [[UNSAFE_STACK_STATIC_TOP]], ptr @__safestack_unsafe_stack_ptr, align 8
+; TLS-NEXT:    [[TMP0:%.*]] = getelementptr i8, ptr addrspace(5) [[UNSAFE_STACK_PTR]], i32 -8
+; TLS-NEXT:    [[A_UNSAFE:%.*]] = addrspacecast ptr addrspace(5) [[TMP0]] to ptr
+; TLS-NEXT:    call void @Capture(ptr [[A_UNSAFE]])
+; TLS-NEXT:    store ptr addrspace(5) [[UNSAFE_STACK_PTR]], ptr @__safestack_unsafe_stack_ptr, align 8
+; TLS-NEXT:    ret void
+;
+entry:
+  %a = alloca i8, align 8
+  call void @Capture(ptr %a)
+  ret void
+}
+
+declare void @Capture(ptr)
+;.
+; TLS: [[META0]] = !{!"unsafe-stack-size", i32 16}
+;.

llvm/test/Transforms/SafeStack/X86/alloca-addrspace.ll

@@ -0,0 +1,27 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -passes=safe-stack -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s --check-prefix=TLS
+
+target datalayout = "A5"
+
+define void @correct_alloca_addrspace() nounwind uwtable safestack {
+; TLS-LABEL: define void @correct_alloca_addrspace(
+; TLS-SAME: ) #[[ATTR0:[0-9]+]] !annotation [[META0:![0-9]+]] {
+; TLS-NEXT:  [[ENTRY:.*:]]
+; TLS-NEXT:    [[UNSAFE_STACK_PTR:%.*]] = load ptr addrspace(5), ptr @__safestack_unsafe_stack_ptr, align 8
+; TLS-NEXT:    [[UNSAFE_STACK_STATIC_TOP:%.*]] = getelementptr i8, ptr addrspace(5) [[UNSAFE_STACK_PTR]], i32 -16
+; TLS-NEXT:    store ptr addrspace(5) [[UNSAFE_STACK_STATIC_TOP]], ptr @__safestack_unsafe_stack_ptr, align 8
+; TLS-NEXT:    [[TMP0:%.*]] = getelementptr i8, ptr addrspace(5) [[UNSAFE_STACK_PTR]], i32 -8
+; TLS-NEXT:    call void @Capture_as5(ptr addrspace(5) [[TMP0]])
+; TLS-NEXT:    store ptr addrspace(5) [[UNSAFE_STACK_PTR]], ptr @__safestack_unsafe_stack_ptr, align 8
+; TLS-NEXT:    ret void
+;
+entry:
+  %a = alloca i8, align 8, addrspace(5)
+  call void @Capture_as5(ptr addrspace(5) %a)
+  ret void
+}
+
+declare void @Capture_as5(ptr addrspace(5))
+;.
+; TLS: [[META0]] = !{!"unsafe-stack-size", i32 16}
+;.