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[safestack] Fix compiler crash in the presence of stack restores.

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A use can be emitted before def in a function with stack restore
points but no static allocas.

llvm-svn: 248455
This commit is contained in:
Evgeniy Stepanov 2015-09-24 01:23:51 +00:00
parent 24e797001b
commit 82c98de471
2 changed files with 37 additions and 7 deletions
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10
lib/Transforms/Instrumentation/SafeStack.cpp
View File

@ -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 &F) {
// 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,

34
test/Transforms/SafeStack/ARM/setjmp.ll Normal file
View File

@ -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
@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*)