Don't build a vector of returns. Just modify the Function in the loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58822 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/StackProtector.cpp b/lib/CodeGen/StackProtector.cpp
index b1f18ed..17f715d 100644
--- a/lib/CodeGen/StackProtector.cpp
+++ b/lib/CodeGen/StackProtector.cpp
@@ -98,31 +98,8 @@
/// - The epilogue checks the value stored in the prologue against the original
/// value. It calls __stack_chk_fail if they differ.
bool StackProtector::InsertStackProtectors() {
- std::vector<BasicBlock*> ReturnBBs;
-
- for (Function::iterator I = F->begin(); I != F->end(); ++I)
- if (isa<ReturnInst>(I->getTerminator()))
- ReturnBBs.push_back(I);
-
- // If this function doesn't return, don't bother with stack protectors.
- if (ReturnBBs.empty()) return false;
-
- // Insert code into the entry block that stores the __stack_chk_guard variable
- // onto the stack.
- BasicBlock &Entry = F->getEntryBlock();
- Instruction *InsertPt = &Entry.front();
-
- const PointerType *GuardTy = PointerType::getUnqual(Type::Int8Ty);
-
- // The global variable for the stack guard.
- Constant *StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", GuardTy);
- LoadInst *LI = new LoadInst(StackGuardVar, "StackGuard", false, InsertPt);
- CallInst::
- Create(Intrinsic::getDeclaration(M, Intrinsic::stackprotector_create),
- LI, "", InsertPt);
-
- // Create the basic block to jump to when the guard check fails.
- BasicBlock *FailBB = CreateFailBB();
+ Constant *StackGuardVar = 0; // The global variable for the stack guard.
+ BasicBlock *FailBB = 0; // The basic block to jump to if check fails.
// Loop through the basic blocks that have return instructions. Convert this:
//
@@ -146,29 +123,55 @@
// call void @__stack_chk_fail()
// unreachable
//
- for (std::vector<BasicBlock*>::iterator
- I = ReturnBBs.begin(), E = ReturnBBs.end(); I != E; ++I) {
- BasicBlock *BB = *I;
- ReturnInst *RI = cast<ReturnInst>(BB->getTerminator());
- Function::iterator InsPt = BB; ++InsPt; // Insertion point for new BB.
+ for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
+ BasicBlock *BB = I;
- // Split the basic block before the return instruction.
- BasicBlock *NewBB = BB->splitBasicBlock(RI, "SP_return");
+ if (isa<ReturnInst>(BB->getTerminator())) {
+ // Create the basic block to jump to when the guard check fails.
+ if (!FailBB)
+ FailBB = CreateFailBB();
- // Move the newly created basic block to the point right after the old basic
- // block so that it's in the "fall through" position.
- NewBB->removeFromParent();
- F->getBasicBlockList().insert(InsPt, NewBB);
+ if (!StackGuardVar)
+ StackGuardVar =
+ M->getOrInsertGlobal("__stack_chk_guard",
+ PointerType::getUnqual(Type::Int8Ty));
- // Generate the stack protector instructions in the old basic block.
- LoadInst *LI1 = new LoadInst(StackGuardVar, "", false, BB);
- CallInst *CI = CallInst::
- Create(Intrinsic::getDeclaration(M, Intrinsic::stackprotector_check),
- "", BB);
- ICmpInst *Cmp = new ICmpInst(CmpInst::ICMP_EQ, CI, LI1, "", BB);
- BranchInst::Create(NewBB, FailBB, Cmp, BB);
+ ReturnInst *RI = cast<ReturnInst>(BB->getTerminator());
+ Function::iterator InsPt = BB; ++InsPt; // Insertion point for new BB.
+ ++I;
+
+ // Split the basic block before the return instruction.
+ BasicBlock *NewBB = BB->splitBasicBlock(RI, "SP_return");
+
+ // Move the newly created basic block to the point right after the old basic
+ // block so that it's in the "fall through" position.
+ NewBB->removeFromParent();
+ F->getBasicBlockList().insert(InsPt, NewBB);
+
+ // Generate the stack protector instructions in the old basic block.
+ LoadInst *LI1 = new LoadInst(StackGuardVar, "", false, BB);
+ CallInst *CI = CallInst::
+ Create(Intrinsic::getDeclaration(M, Intrinsic::stackprotector_check),
+ "", BB);
+ ICmpInst *Cmp = new ICmpInst(CmpInst::ICMP_EQ, CI, LI1, "", BB);
+ BranchInst::Create(NewBB, FailBB, Cmp, BB);
+ }
}
+ // Return if we didn't modify any basic blocks. I.e., there are no return
+ // statements in the function.
+ if (!FailBB) return false;
+
+ // Insert code into the entry block that stores the __stack_chk_guard variable
+ // onto the stack.
+ BasicBlock &Entry = F->getEntryBlock();
+ Instruction *InsertPt = &Entry.front();
+
+ LoadInst *LI = new LoadInst(StackGuardVar, "StackGuard", false, InsertPt);
+ CallInst::
+ Create(Intrinsic::getDeclaration(M, Intrinsic::stackprotector_create),
+ LI, "", InsertPt);
+
return true;
}