/// - The epilogue checks the value stored in the prologue against the original
/// value. It calls __stack_chk_fail if they differ.
bool StackProtector::InsertStackProtectors() {
- BasicBlock *FailBB = 0; // The basic block to jump to if check fails.
- BasicBlock *FailBBDom = 0; // FailBB's dominator.
+ bool HasPrologue = false;
AllocaInst *AI = 0; // Place on stack that stores the stack guard.
Value *StackGuardVar = 0; // The stack guard variable.
ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator());
if (!RI) continue;
- if (!FailBB) {
+ if (!HasPrologue) {
+ HasPrologue = true;
CreatePrologue(F, M, RI, TLI, Trip, AI, StackGuardVar);
- // Create the basic block to jump to when the guard check fails.
- FailBB = CreateFailBB();
}
// For each block with a return instruction, convert this:
// call void @__stack_chk_fail()
// unreachable
+ // Create the fail basic block.
+ BasicBlock *FailBB = CreateFailBB();
+
// Split the basic block before the return instruction.
BasicBlock *NewBB = BB->splitBasicBlock(RI, "SP_return");
+ // Update the dominator tree if we need to.
if (DT && DT->isReachableFromEntry(BB)) {
DT->addNewBlock(NewBB, BB);
- FailBBDom = FailBBDom ? DT->findNearestCommonDominator(FailBBDom, BB) :BB;
+ DT->addNewBlock(FailBB, BB);
}
// Remove default branch instruction to the new BB.
// Return if we didn't modify any basic blocks. I.e., there are no return
// statements in the function.
- if (!FailBB) return false;
-
- if (DT && FailBBDom)
- DT->addNewBlock(FailBB, FailBBDom);
+ if (!HasPrologue)
+ return false;
return true;
}
; LINUX-I386-LABEL: test19d:
; LINUX-I386: mov{{l|q}} %gs:
; LINUX-I386: calll __stack_chk_fail
+; LINUX-I386-NOT: calll __stack_chk_fail
; LINUX-X64-LABEL: test19d:
; LINUX-X64: mov{{l|q}} %fs:
; LINUX-X64: callq __stack_chk_fail
+; LINUX-X64-NOT: callq __stack_chk_fail
; LINUX-KERNEL-X64-LABEL: test19d:
; LINUX-KERNEL-X64: mov{{l|q}} %gs:
; LINUX-KERNEL-X64: callq __stack_chk_fail
+; LINUX-KERNEL-X64-NOT: callq ___stack_chk_fail
; DARWIN-X64-LABEL: test19d:
; DARWIN-X64: mov{{l|q}} ___stack_chk_guard
; DARWIN-X64: callq ___stack_chk_fail
+; DARWIN-X64-NOT: callq ___stack_chk_fail
%c = alloca %struct.pair, align 4
%exn.slot = alloca i8*
%ehselector.slot = alloca i32