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-rw-r--r--llvm/lib/CodeGen/SafeStack.cpp39
-rw-r--r--llvm/test/Transforms/SafeStack/array-aligned.ll7
-rw-r--r--llvm/test/Transforms/SafeStack/array.ll7
-rw-r--r--llvm/test/Transforms/SafeStack/phi.ll35
-rw-r--r--llvm/test/Transforms/SafeStack/sink-to-use.ll22
-rw-r--r--llvm/test/Transforms/SafeStack/struct.ll7
6 files changed, 97 insertions, 20 deletions
diff --git a/llvm/lib/CodeGen/SafeStack.cpp b/llvm/lib/CodeGen/SafeStack.cpp
index 28f5ed861ab..457acb1503c 100644
--- a/llvm/lib/CodeGen/SafeStack.cpp
+++ b/llvm/lib/CodeGen/SafeStack.cpp
@@ -606,16 +606,39 @@ Value *SafeStack::moveStaticAllocasToUnsafeStack(
StaticOffset += Size;
StaticOffset = alignTo(StaticOffset, Align);
- Value *Off = IRB.CreateGEP(BasePointer, // BasePointer is i8*
- ConstantInt::get(Int32Ty, -StaticOffset));
- Value *NewAI = IRB.CreateBitCast(Off, AI->getType(), AI->getName());
- if (AI->hasName() && isa<Instruction>(NewAI))
- cast<Instruction>(NewAI)->takeName(AI);
-
- // Replace alloc with the new location.
replaceDbgDeclareForAlloca(AI, BasePointer, DIB, /*Deref=*/true, -StaticOffset);
replaceDbgValueForAlloca(AI, BasePointer, DIB, -StaticOffset);
- AI->replaceAllUsesWith(NewAI);
+
+ // Replace uses of the alloca with the new location.
+ // Insert address calculation close to each use to work around PR27844.
+ std::string Name = std::string(AI->getName()) + ".unsafe";
+ while (!AI->use_empty()) {
+ Use &U = *AI->use_begin();
+ Instruction *User = cast<Instruction>(U.getUser());
+
+ Instruction *InsertBefore;
+ if (auto *PHI = dyn_cast<PHINode>(User))
+ InsertBefore = PHI->getIncomingBlock(U)->getTerminator();
+ else
+ InsertBefore = User;
+
+ IRBuilder<> IRBUser(InsertBefore);
+ Value *Off = IRBUser.CreateGEP(BasePointer, // BasePointer is i8*
+ ConstantInt::get(Int32Ty, -StaticOffset));
+ Value *Replacement = IRBUser.CreateBitCast(Off, AI->getType(), Name);
+
+ if (auto *PHI = dyn_cast<PHINode>(User)) {
+ // PHI nodes may have multiple incoming edges from the same BB (why??),
+ // all must be updated at once with the same incoming value.
+ auto *BB = PHI->getIncomingBlock(U);
+ for (unsigned I = 0; I < PHI->getNumIncomingValues(); ++I)
+ if (PHI->getIncomingBlock(I) == BB)
+ PHI->setIncomingValue(I, Replacement);
+ } else {
+ U.set(Replacement);
+ }
+ }
+
AI->eraseFromParent();
}
diff --git a/llvm/test/Transforms/SafeStack/array-aligned.ll b/llvm/test/Transforms/SafeStack/array-aligned.ll
index 4676903ec77..26558e4fa81 100644
--- a/llvm/test/Transforms/SafeStack/array-aligned.ll
+++ b/llvm/test/Transforms/SafeStack/array-aligned.ll
@@ -13,16 +13,15 @@ entry:
; CHECK: store i8* %[[USST]], i8** @__safestack_unsafe_stack_ptr
- ; CHECK: %[[AADDR:.*]] = alloca i8*, align 8
%a.addr = alloca i8*, align 8
-
- ; CHECK: %[[BUFPTR:.*]] = getelementptr i8, i8* %[[USP]], i32 -16
- ; CHECK: %[[BUFPTR2:.*]] = bitcast i8* %[[BUFPTR]] to [16 x i8]*
%buf = alloca [16 x i8], align 16
+ ; CHECK: %[[AADDR:.*]] = alloca i8*, align 8
; CHECK: store i8* {{.*}}, i8** %[[AADDR]], align 8
store i8* %a, i8** %a.addr, align 8
+ ; CHECK: %[[BUFPTR:.*]] = getelementptr i8, i8* %[[USP]], i32 -16
+ ; CHECK: %[[BUFPTR2:.*]] = bitcast i8* %[[BUFPTR]] to [16 x i8]*
; CHECK: %[[GEP:.*]] = getelementptr inbounds [16 x i8], [16 x i8]* %[[BUFPTR2]], i32 0, i32 0
%gep = getelementptr inbounds [16 x i8], [16 x i8]* %buf, i32 0, i32 0
diff --git a/llvm/test/Transforms/SafeStack/array.ll b/llvm/test/Transforms/SafeStack/array.ll
index 564213e6d58..7dcf7fa50d9 100644
--- a/llvm/test/Transforms/SafeStack/array.ll
+++ b/llvm/test/Transforms/SafeStack/array.ll
@@ -17,16 +17,15 @@ entry:
; CHECK: store i8* %[[USST]], i8** @__safestack_unsafe_stack_ptr
- ; CHECK: %[[AADDR:.*]] = alloca i8*, align 8
%a.addr = alloca i8*, align 8
-
- ; CHECK: %[[BUFPTR:.*]] = getelementptr i8, i8* %[[USP]], i32 -4
- ; CHECK: %[[BUFPTR2:.*]] = bitcast i8* %[[BUFPTR]] to [4 x i8]*
%buf = alloca [4 x i8], align 1
+ ; CHECK: %[[AADDR:.*]] = alloca i8*, align 8
; CHECK: store i8* {{.*}}, i8** %[[AADDR]], align 8
store i8* %a, i8** %a.addr, align 8
+ ; CHECK: %[[BUFPTR:.*]] = getelementptr i8, i8* %[[USP]], i32 -4
+ ; CHECK: %[[BUFPTR2:.*]] = bitcast i8* %[[BUFPTR]] to [4 x i8]*
; CHECK: %[[GEP:.*]] = getelementptr inbounds [4 x i8], [4 x i8]* %[[BUFPTR2]], i32 0, i32 0
%gep = getelementptr inbounds [4 x i8], [4 x i8]* %buf, i32 0, i32 0
diff --git a/llvm/test/Transforms/SafeStack/phi.ll b/llvm/test/Transforms/SafeStack/phi.ll
new file mode 100644
index 00000000000..3ee56aa0f56
--- /dev/null
+++ b/llvm/test/Transforms/SafeStack/phi.ll
@@ -0,0 +1,35 @@
+; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
+; RUN: opt -safe-stack -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s
+
+define void @f(i1 %d1, i1 %d2) safestack {
+entry:
+; CHECK-LABEL: define void @f(
+; CHECK: %[[USP:.*]] = load i8*, i8** @__safestack_unsafe_stack_ptr
+; CHECK-NEXT: getelementptr i8, i8* %[[USP]], i32 -16
+; CHECK: br i1 %d1, label %[[BB0:.*]], label %[[BB1:.*]]
+ %a = alloca i32, align 8
+ %b = alloca i32, align 8
+ br i1 %d1, label %bb0, label %bb1
+
+bb0:
+; CHECK: [[BB0]]:
+; CHECK: %[[Ai8:.*]] = getelementptr i8, i8* %unsafe_stack_ptr, i32
+; CHECK: %[[AUNSAFE:.*]] = bitcast i8* %[[Ai8]] to i32*
+; CHECK: br i1
+ br i1 %d2, label %bb2, label %bb2
+
+bb1:
+; CHECK: [[BB1]]:
+; CHECK: %[[Bi8:.*]] = getelementptr i8, i8* %unsafe_stack_ptr, i32
+; CHECK: %[[BUNSAFE:.*]] = bitcast i8* %[[Bi8]] to i32*
+; CHECK: br label
+ br label %bb2
+
+bb2:
+; CHECK: phi i32* [ %[[AUNSAFE]], %[[BB0]] ], [ %[[AUNSAFE]], %[[BB0]] ], [ %[[BUNSAFE]], %[[BB1]] ]
+ %c = phi i32* [ %a, %bb0 ], [ %a, %bb0 ], [ %b, %bb1 ]
+ call void @capture(i32* %c)
+ ret void
+}
+
+declare void @capture(i32*)
diff --git a/llvm/test/Transforms/SafeStack/sink-to-use.ll b/llvm/test/Transforms/SafeStack/sink-to-use.ll
new file mode 100644
index 00000000000..e208ce1da9d
--- /dev/null
+++ b/llvm/test/Transforms/SafeStack/sink-to-use.ll
@@ -0,0 +1,22 @@
+; Test that unsafe alloca address calculation is done immediately before each use.
+; RUN: opt -safe-stack -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s
+; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
+
+define void @f() safestack {
+entry:
+ %x0 = alloca i32, align 4
+ %x1 = alloca i32, align 4
+
+; CHECK: %[[A:.*]] = getelementptr i8, i8* %{{.*}}, i32 -4
+; CHECK: %[[X0:.*]] = bitcast i8* %[[A]] to i32*
+; CHECK: call void @use(i32* %[[X0]])
+ call void @use(i32* %x0)
+
+; CHECK: %[[B:.*]] = getelementptr i8, i8* %{{.*}}, i32 -8
+; CHECK: %[[X1:.*]] = bitcast i8* %[[B]] to i32*
+; CHECK: call void @use(i32* %[[X1]])
+ call void @use(i32* %x1)
+ ret void
+}
+
+declare void @use(i32*)
diff --git a/llvm/test/Transforms/SafeStack/struct.ll b/llvm/test/Transforms/SafeStack/struct.ll
index 12a0085a2cc..b64803d160c 100644
--- a/llvm/test/Transforms/SafeStack/struct.ll
+++ b/llvm/test/Transforms/SafeStack/struct.ll
@@ -15,16 +15,15 @@ entry:
; CHECK: store i8* %[[USST]], i8** @__safestack_unsafe_stack_ptr
- ; CHECK: %[[AADDR:.*]] = alloca i8*, align 8
%a.addr = alloca i8*, align 8
-
- ; CHECK: %[[BUFPTR:.*]] = getelementptr i8, i8* %[[USP]], i32 -16
- ; CHECK: %[[BUFPTR2:.*]] = bitcast i8* %[[BUFPTR]] to %struct.foo*
%buf = alloca %struct.foo, align 1
+ ; CHECK: %[[AADDR:.*]] = alloca i8*, align 8
; CHECK: store i8* {{.*}}, i8** %[[AADDR]], align 8
store i8* %a, i8** %a.addr, align 8
+ ; CHECK: %[[BUFPTR:.*]] = getelementptr i8, i8* %[[USP]], i32 -16
+ ; CHECK: %[[BUFPTR2:.*]] = bitcast i8* %[[BUFPTR]] to %struct.foo*
; CHECK: %[[GEP:.*]] = getelementptr inbounds %struct.foo, %struct.foo* %[[BUFPTR2]], i32 0, i32 0, i32 0
%gep = getelementptr inbounds %struct.foo, %struct.foo* %buf, i32 0, i32 0, i32 0
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