[llvm] r248455 - [safestack] Fix compiler crash in the presence of stack restores.
Evgeniy Stepanov via llvm-commits
llvm-commits at lists.llvm.org
Wed Sep 23 18:23:51 PDT 2015
Author: eugenis
Date: Wed Sep 23 20:23:51 2015
New Revision: 248455
URL: http://llvm.org/viewvc/llvm-project?rev=248455&view=rev
Log:
[safestack] Fix compiler crash in the presence of stack restores.
A use can be emitted before def in a function with stack restore
points but no static allocas.
Added:
llvm/trunk/test/Transforms/SafeStack/ARM/setjmp.ll
Modified:
llvm/trunk/lib/Transforms/Instrumentation/SafeStack.cpp
Modified: llvm/trunk/lib/Transforms/Instrumentation/SafeStack.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/SafeStack.cpp?rev=248455&r1=248454&r2=248455&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/SafeStack.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/SafeStack.cpp Wed Sep 23 20:23:51 2015
@@ -210,7 +210,7 @@ class SafeStack : public FunctionPass {
/// \returns A local variable in which to maintain the dynamic top of the
/// unsafe stack if needed.
AllocaInst *
- createStackRestorePoints(Function &F,
+ createStackRestorePoints(IRBuilder<> &IRB, Function &F,
ArrayRef<Instruction *> StackRestorePoints,
Value *StaticTop, bool NeedDynamicTop);
@@ -332,16 +332,12 @@ void SafeStack::findInsts(Function &F,
}
AllocaInst *
-SafeStack::createStackRestorePoints(Function &F,
+SafeStack::createStackRestorePoints(IRBuilder<> &IRB, Function &F,
ArrayRef<Instruction *> StackRestorePoints,
Value *StaticTop, bool NeedDynamicTop) {
if (StackRestorePoints.empty())
return nullptr;
- IRBuilder<> IRB(StaticTop
- ? cast<Instruction>(StaticTop)->getNextNode()
- : (Instruction *)F.getEntryBlock().getFirstInsertionPt());
-
// We need the current value of the shadow stack pointer to restore
// after longjmp or exception catching.
@@ -613,7 +609,7 @@ bool SafeStack::runOnFunction(Function &
// FIXME: a better alternative might be to store the unsafe stack pointer
// before setjmp / invoke instructions.
AllocaInst *DynamicTop = createStackRestorePoints(
- F, StackRestorePoints, StaticTop, !DynamicAllocas.empty());
+ IRB, F, StackRestorePoints, StaticTop, !DynamicAllocas.empty());
// Handle dynamic allocas.
moveDynamicAllocasToUnsafeStack(F, UnsafeStackPtr, DynamicTop,
Added: llvm/trunk/test/Transforms/SafeStack/ARM/setjmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SafeStack/ARM/setjmp.ll?rev=248455&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/SafeStack/ARM/setjmp.ll (added)
+++ llvm/trunk/test/Transforms/SafeStack/ARM/setjmp.ll Wed Sep 23 20:23:51 2015
@@ -0,0 +1,34 @@
+; Test stack pointer restore after setjmp() with the function-call safestack ABI.
+; RUN: opt -safe-stack -S -mtriple=arm-linux-androideabi < %s -o - | FileCheck %s
+
+ at env = global [64 x i32] zeroinitializer, align 4
+
+define void @f(i32 %b) safestack {
+entry:
+; CHECK: %[[SPA:.*]] = call i8** @__safestack_pointer_address()
+; CHECK: %[[USDP:.*]] = alloca i8*
+; CHECK: %[[USP:.*]] = load i8*, i8** %[[SPA]]
+; CHECK: store i8* %[[USP]], i8** %[[USDP]]
+; CHECK: call i32 @setjmp
+
+ %call = call i32 @setjmp(i32* getelementptr inbounds ([64 x i32], [64 x i32]* @env, i32 0, i32 0)) returns_twice
+
+; CHECK: %[[USP2:.*]] = load i8*, i8** %[[USDP]]
+; CHECK: store i8* %[[USP2]], i8** %[[SPA]]
+
+ %tobool = icmp eq i32 %b, 0
+ br i1 %tobool, label %if.end, label %if.then
+
+if.then:
+ %0 = alloca [42 x i8], align 1
+ %.sub = getelementptr inbounds [42 x i8], [42 x i8]* %0, i32 0, i32 0
+ call void @_Z7CapturePv(i8* %.sub)
+ br label %if.end
+
+if.end:
+ ret void
+}
+
+declare i32 @setjmp(i32*) returns_twice
+
+declare void @_Z7CapturePv(i8*)
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