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-rw-r--r--contrib/llvm/lib/CodeGen/ShadowStackGCLowering.cpp116
1 files changed, 1 insertions, 115 deletions
diff --git a/contrib/llvm/lib/CodeGen/ShadowStackGCLowering.cpp b/contrib/llvm/lib/CodeGen/ShadowStackGCLowering.cpp
index 1efc440..ff7d205 100644
--- a/contrib/llvm/lib/CodeGen/ShadowStackGCLowering.cpp
+++ b/contrib/llvm/lib/CodeGen/ShadowStackGCLowering.cpp
@@ -23,6 +23,7 @@
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
+#include "llvm/Transforms/Utils/EscapeEnumerator.h"
using namespace llvm;
@@ -81,121 +82,6 @@ ShadowStackGCLowering::ShadowStackGCLowering()
initializeShadowStackGCLoweringPass(*PassRegistry::getPassRegistry());
}
-namespace {
-/// EscapeEnumerator - This is a little algorithm to find all escape points
-/// from a function so that "finally"-style code can be inserted. In addition
-/// to finding the existing return and unwind instructions, it also (if
-/// necessary) transforms any call instructions into invokes and sends them to
-/// a landing pad.
-///
-/// It's wrapped up in a state machine using the same transform C# uses for
-/// 'yield return' enumerators, This transform allows it to be non-allocating.
-class EscapeEnumerator {
- Function &F;
- const char *CleanupBBName;
-
- // State.
- int State;
- Function::iterator StateBB, StateE;
- IRBuilder<> Builder;
-
-public:
- EscapeEnumerator(Function &F, const char *N = "cleanup")
- : F(F), CleanupBBName(N), State(0), Builder(F.getContext()) {}
-
- IRBuilder<> *Next() {
- switch (State) {
- default:
- return nullptr;
-
- case 0:
- StateBB = F.begin();
- StateE = F.end();
- State = 1;
-
- case 1:
- // Find all 'return', 'resume', and 'unwind' instructions.
- while (StateBB != StateE) {
- BasicBlock *CurBB = &*StateBB++;
-
- // Branches and invokes do not escape, only unwind, resume, and return
- // do.
- TerminatorInst *TI = CurBB->getTerminator();
- if (!isa<ReturnInst>(TI) && !isa<ResumeInst>(TI))
- continue;
-
- Builder.SetInsertPoint(TI);
- return &Builder;
- }
-
- State = 2;
-
- // Find all 'call' instructions.
- SmallVector<Instruction *, 16> Calls;
- for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
- for (BasicBlock::iterator II = BB->begin(), EE = BB->end(); II != EE;
- ++II)
- if (CallInst *CI = dyn_cast<CallInst>(II))
- if (!CI->getCalledFunction() ||
- !CI->getCalledFunction()->getIntrinsicID())
- Calls.push_back(CI);
-
- if (Calls.empty())
- return nullptr;
-
- // Create a cleanup block.
- LLVMContext &C = F.getContext();
- BasicBlock *CleanupBB = BasicBlock::Create(C, CleanupBBName, &F);
- Type *ExnTy =
- StructType::get(Type::getInt8PtrTy(C), Type::getInt32Ty(C), nullptr);
- if (!F.hasPersonalityFn()) {
- Constant *PersFn = F.getParent()->getOrInsertFunction(
- "__gcc_personality_v0",
- FunctionType::get(Type::getInt32Ty(C), true));
- F.setPersonalityFn(PersFn);
- }
- LandingPadInst *LPad =
- LandingPadInst::Create(ExnTy, 1, "cleanup.lpad", CleanupBB);
- LPad->setCleanup(true);
- ResumeInst *RI = ResumeInst::Create(LPad, CleanupBB);
-
- // Transform the 'call' instructions into 'invoke's branching to the
- // cleanup block. Go in reverse order to make prettier BB names.
- SmallVector<Value *, 16> Args;
- for (unsigned I = Calls.size(); I != 0;) {
- CallInst *CI = cast<CallInst>(Calls[--I]);
-
- // Split the basic block containing the function call.
- BasicBlock *CallBB = CI->getParent();
- BasicBlock *NewBB = CallBB->splitBasicBlock(
- CI->getIterator(), CallBB->getName() + ".cont");
-
- // Remove the unconditional branch inserted at the end of CallBB.
- CallBB->getInstList().pop_back();
- NewBB->getInstList().remove(CI);
-
- // Create a new invoke instruction.
- Args.clear();
- CallSite CS(CI);
- Args.append(CS.arg_begin(), CS.arg_end());
-
- InvokeInst *II =
- InvokeInst::Create(CI->getCalledValue(), NewBB, CleanupBB, Args,
- CI->getName(), CallBB);
- II->setCallingConv(CI->getCallingConv());
- II->setAttributes(CI->getAttributes());
- CI->replaceAllUsesWith(II);
- delete CI;
- }
-
- Builder.SetInsertPoint(RI);
- return &Builder;
- }
- }
-};
-}
-
-
Constant *ShadowStackGCLowering::GetFrameMap(Function &F) {
// doInitialization creates the abstract type of this value.
Type *VoidPtr = Type::getInt8PtrTy(F.getContext());
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