[llvm] e4b352a - Revert "DwarfEHPrepare: insert extra unwind paths for stack protector to instrument"
Tim Northover via llvm-commits
llvm-commits at lists.llvm.org
Thu Mar 16 04:56:29 PDT 2023
Author: Tim Northover
Date: 2023-03-16T11:55:53Z
New Revision: e4b352a0b9a557db5998838bf43dd36f2742ada5
URL: https://github.com/llvm/llvm-project/commit/e4b352a0b9a557db5998838bf43dd36f2742ada5
DIFF: https://github.com/llvm/llvm-project/commit/e4b352a0b9a557db5998838bf43dd36f2742ada5.diff
LOG: Revert "DwarfEHPrepare: insert extra unwind paths for stack protector to instrument"
It's caused more failures than are trivially fixable.
This reverts commit 203b6f31bb71ce63488eb96b303e000e91aee376.
Added:
Modified:
llvm/lib/CodeGen/DwarfEHPrepare.cpp
Removed:
llvm/test/CodeGen/Generic/safestack-unwind.ll
################################################################################
diff --git a/llvm/lib/CodeGen/DwarfEHPrepare.cpp b/llvm/lib/CodeGen/DwarfEHPrepare.cpp
index a8af70669b329..32c94de7280cb 100644
--- a/llvm/lib/CodeGen/DwarfEHPrepare.cpp
+++ b/llvm/lib/CodeGen/DwarfEHPrepare.cpp
@@ -18,7 +18,6 @@
#include "llvm/Analysis/DomTreeUpdater.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/RuntimeLibcalls.h"
-#include "llvm/CodeGen/StackProtector.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
@@ -29,7 +28,6 @@
#include "llvm/IR/Dominators.h"
#include "llvm/IR/EHPersonalities.h"
#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
@@ -39,7 +37,6 @@
#include "llvm/Target/TargetMachine.h"
#include "llvm/TargetParser/Triple.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include <cstddef>
using namespace llvm;
@@ -169,125 +166,7 @@ size_t DwarfEHPrepare::pruneUnreachableResumes(
return ResumesLeft;
}
-/// If a landingpad block doesn't already have a cleanup case, add one
-/// that feeds directly into a resume instruction.
-static void addCleanupResumeToLandingPad(BasicBlock &BB, DomTreeUpdater *DTU) {
- LandingPadInst *LP = BB.getLandingPadInst();
- if (LP->isCleanup())
- return;
-
- // There will usually be code testing for the other kinds of exception
- // immediately after the landingpad. Working out the far end of that chain is
- // tricky, so put our test for the new cleanup case (i.e. selector == 0) at
- // the beginning.
- BasicBlock *ContBB = SplitBlock(&BB, LP->getNextNode(), DTU);
- BB.getTerminator()->eraseFromParent();
-
- LP->setCleanup(true);
- IRBuilder<> B(&BB);
- Value *Selector = B.CreateExtractValue(LP, 1);
- Value *Cmp = B.CreateICmpEQ(Selector, ConstantInt::get(Selector->getType(), 0));
-
- Function *F = BB.getParent();
- LLVMContext &Ctx = F->getContext();
- BasicBlock *ResumeBB = BasicBlock::Create(Ctx, "resume", F);
- ResumeInst::Create(LP, ResumeBB);
-
- B.CreateCondBr(Cmp, ResumeBB, ContBB);
-}
-
-/// Create a basic block that has a `landingpad` instruction feeding
-/// directly into a `resume`. Will be set to the unwind destination of a new
-/// invoke.
-static BasicBlock *createCleanupResumeBB(Function &F, Type *LandingPadTy) {
- LLVMContext &Ctx = F.getContext();
- BasicBlock *BB = BasicBlock::Create(Ctx, "cleanup_resume", &F);
- IRBuilder<> B(BB);
-
- // If this is going to be the only landingpad in the function, synthesize the
- // standard type all ABIs use, which is essentially `{ ptr, i32 }`.
- if (!LandingPadTy)
- LandingPadTy =
- StructType::get(Type::getInt8PtrTy(Ctx), IntegerType::get(Ctx, 32));
-
- LandingPadInst *Except = B.CreateLandingPad(LandingPadTy, 0);
- Except->setCleanup(true);
- B.CreateResume(Except);
- return BB;
-}
-
-/// Convert a call that might throw into an invoke that unwinds to the specified
-/// simple landingpad/resume block.
-static void changeCallToInvokeResume(CallInst &CI, BasicBlock *CleanupResumeBB,
- DomTreeUpdater *DTU) {
- BasicBlock *BB = CI.getParent();
- BasicBlock *ContBB = SplitBlock(BB, &CI, DTU);
- BB->getTerminator()->eraseFromParent();
-
- IRBuilder<> B(BB);
- SmallVector<Value *> Args(CI.args());
- SmallVector<OperandBundleDef> Bundles;
- CI.getOperandBundlesAsDefs(Bundles);
- InvokeInst *NewCall =
- B.CreateInvoke(CI.getFunctionType(), CI.getCalledOperand(), ContBB,
- CleanupResumeBB, Args, Bundles, CI.getName());
- NewCall->setAttributes(CI.getAttributes());
- NewCall->setCallingConv(CI.getCallingConv());
- NewCall->copyMetadata(CI);
-
- CI.replaceAllUsesWith(NewCall);
- CI.eraseFromParent();
-}
-
-/// Ensure that any call in this function that might throw has an associated
-/// cleanup/resume that the stack protector can instrument later. Existing
-/// invokes will get an added `cleanup` clause if needed, calls will be
-/// converted to an invoke with trivial unwind followup.
-static void addCleanupPathsForStackProtector(Function &F, DomTreeUpdater *DTU) {
- // First add cleanup -> resume paths to all existing landingpads, noting what
- // type landingpads in this function actually have along the way.
- Type *LandingPadTy = nullptr;
- for (Function::iterator FI = F.begin(); FI != F.end(); ++FI) {
- BasicBlock &BB = *FI;
- if (LandingPadInst *LP = BB.getLandingPadInst()) {
- // We can assume the type is broadly compatible with { ptr, i32 } since
- // other parts of this pass already try to extract values from it.
- LandingPadTy = LP->getType();
- addCleanupResumeToLandingPad(BB, DTU);
- }
- }
-
- // Next convert any call that might throw into an invoke to a resume
- // instruction for later instrumentation.
- BasicBlock *CleanupResumeBB = nullptr;
- for (Function::iterator FI = F.begin(); FI != F.end(); ++FI) {
- BasicBlock &BB = *FI;
- for (Instruction &I : BB) {
- CallInst *CI = dyn_cast<CallInst>(&I);
- if (!CI || CI->doesNotThrow())
- continue;
-
- // Tail calls cannot use our stack so no need to check whether it was
- // corrupted.
- if (CI->isTailCall())
- continue;
-
- if (!CleanupResumeBB)
- CleanupResumeBB = createCleanupResumeBB(F, LandingPadTy);
-
- changeCallToInvokeResume(*CI, CleanupResumeBB, DTU);
-
- // This block has been split, start again on its continuation.
- break;
- }
- }
-}
-
bool DwarfEHPrepare::InsertUnwindResumeCalls() {
- if (F.hasPersonalityFn() &&
- StackProtector::requiresStackProtector(&F, nullptr))
- addCleanupPathsForStackProtector(F, DTU);
-
SmallVector<ResumeInst *, 16> Resumes;
SmallVector<LandingPadInst *, 16> CleanupLPads;
if (F.doesNotThrow())
diff --git a/llvm/test/CodeGen/Generic/safestack-unwind.ll b/llvm/test/CodeGen/Generic/safestack-unwind.ll
deleted file mode 100644
index 66ff7409a68c7..0000000000000
--- a/llvm/test/CodeGen/Generic/safestack-unwind.ll
+++ /dev/null
@@ -1,140 +0,0 @@
-; RUN: opt --dwarfehprepare %s -S -o - -mtriple=aarch64-linux-gnu | FileCheck %s
-
-define void @call() sspreq personality ptr @__gxx_personality_v0 {
-; CHECK-LABEL: define void @call()
-; CHECK: invoke void @bar()
-; CHECK: to label %[[CONT:.*]] unwind label %[[CLEANUP:.*]]
-; CHECK: [[CONT]]:
-; CHECK: ret void
-; CHECK: [[CLEANUP]]:
-; CHECK: [[LP:%.*]] = landingpad { ptr, i32 }
-; CHECK: cleanup
-; CHECK: [[EXN:%.*]] = extractvalue { ptr, i32 } [[LP]], 0
-; CHECK: call void @_Unwind_Resume(ptr [[EXN]])
-; CHECK: unreachable
- call void @bar()
- ret void
-}
-
-define void @invoke_no_cleanup() sspreq personality ptr @__gxx_personality_v0 {
-; CHECK-LABEL: define void @invoke_no_cleanup
-; CHECK: invoke void @bar()
-; CHECK: to label %done unwind label %catch
-
-; CHECK: catch:
-; CHECK: [[LP:%.*]] = landingpad { ptr, i32 }
-; CHECK: cleanup
-; CHECK: catch ptr null
-; CHECK: [[SEL:%.*]] = extractvalue { ptr, i32 } [[LP]], 1
-; CHECK: [[CMP:%.*]] = icmp eq i32 [[SEL]], 0
-; CHECK: br i1 [[CMP]], label %[[RESUME:.*]], label %[[SPLIT:.*]]
-
-; CHECK: [[SPLIT]]:
-; CHECK: br label %done
-
-; CHECK: done:
-; CHECK: ret void
-
-; CHECK: [[RESUME]]:
-; CHECK: [[EXN:%.*]] = extractvalue { ptr, i32 } [[LP]], 0
-; CHECK: call void @_Unwind_Resume(ptr [[EXN]])
-; CHECK: unreachable
- invoke void @bar() to label %done unwind label %catch
-
-catch:
- %lp = landingpad { ptr, i32 }
- catch ptr null
- br label %done
-
-done:
- ret void
-}
-
-define void @invoke_no_cleanup_catches() sspreq personality ptr @__gxx_personality_v0 {
-; CHECK-LABEL: define void @invoke_no_cleanup_catches
-; CHECK: invoke void @bar()
-; CHECK: to label %done unwind label %catch
-
-; CHECK: catch:
-; CHECK: [[LP:%.*]] = landingpad { ptr, i32 }
-; CHECK: cleanup
-; CHECK: catch ptr null
-; CHECK: [[SEL:%.*]] = extractvalue { ptr, i32 } [[LP]], 1
-; CEHCK: [[CMP:%.*]] = icmp eq i32 [[SEL]], 0
-; CEHCK: br i1 [[CMP]], label %[[RESUME:.*]], label %[[SPLIT:.*]]
-
-; CHECK: [[SPLIT]]:
-; CHECK: %exn = extractvalue { ptr, i32 } %lp, 0
-; CHECK: invoke ptr @__cxa_begin_catch(ptr %exn)
-; CHECK: to label %[[SPLIT2:.*]] unwind label %[[CLEANUP_RESUME:.*]]
-
-; CHECK: [[SPLIT2]]:
-; CHECK: invoke void @__cxa_end_catch()
-; CHECK: to label %[[SPLIT3:.*]] unwind label %[[CLEANUP_RESUME:.*]]
-
-; CHECK: [[SPLIT3]]:
-; CHECK: br label %done
-
-; CHECK: done:
-; CHECK: ret void
-
-; CHECK: [[RESUME]]:
-; CHECK: [[EXN1:%.*]] = extractvalue { ptr, i32 } [[LP]], 0
-; CHECK: br label %[[RESUME_MERGE:.*]]
-
-; CHECK: [[CLEANUP_RESUME]]:
-; CHECK: [[LP:%.*]] = landingpad { ptr, i32 }
-; CHECK: cleanup
-; CHECK: [[EXN2:%.*]] = extractvalue { ptr, i32 } [[LP]], 0
-; CHECK: br label %[[RESUME_MERGE]]
-
-; CHECK: [[RESUME_MERGE]]:
-; CHECK: [[EXN_PHI:%.*]] = phi ptr [ [[EXN1]], %[[RESUME]] ], [ [[EXN2]], %[[CLEANUP_RESUME]] ]
-; CHECK: call void @_Unwind_Resume(ptr [[EXN_PHI]])
-; CHECK: unreachable
- invoke void @bar() to label %done unwind label %catch
-
-catch:
- %lp = landingpad { ptr, i32 }
- catch ptr null
- %exn = extractvalue { ptr, i32 } %lp, 0
- call ptr @__cxa_begin_catch(ptr %exn)
- call void @__cxa_end_catch()
- br label %done
-
-done:
- ret void
-}
-
-; Don't try to invoke any intrinsics.
-define ptr @call_intrinsic() sspreq personality ptr @__gxx_personality_v0 {
-; CHECK-LABEL: define ptr @call_intrinsic
-; CHECK: call ptr @llvm.frameaddress.p0(i32 0)
- %res = call ptr @llvm.frameaddress.p0(i32 0)
- ret ptr %res
-}
-
-; Check we go along with the existing landingpad type, even if it's a bit
-; outside the normal.
-define void @weird_landingpad() sspreq personality ptr @__gxx_personality_v0 {
-; CHECK-LABEL: define void @weird_landingpad
-; CHECK: landingpad { ptr, i64 }
-; CHECK: landingpad { ptr, i64 }
- invoke void @bar() to label %done unwind label %catch
-
-catch:
- %lp = landingpad { ptr, i64 }
- catch ptr null
- resume { ptr, i64 } %lp
-; br label %done
-
-done:
- call void @bar()
- ret void
-}
-
-declare void @bar()
-declare i32 @__gxx_personality_v0(...)
-declare ptr @__cxa_begin_catch(ptr)
-declare void @__cxa_end_catch()
-declare ptr @llvm.frameaddress.p0(i32)
More information about the llvm-commits
mailing list