[PATCH] D148654: Modify BoundsSan to improve debuggability

[Oskar Wirga via Phabricator via cfe-commits]

oskarwirga updated this revision to Diff 518933.
oskarwirga edited the summary of this revision.
oskarwirga added a comment.

Update the diff to use the `nomerge` attribute


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D148654/new/

https://reviews.llvm.org/D148654

Files:
  clang/lib/CodeGen/CGExpr.cpp
  llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp


Index: clang/lib/CodeGen/CGExpr.cpp
===================================================================
--- clang/lib/CodeGen/CGExpr.cpp
+++ clang/lib/CodeGen/CGExpr.cpp
@@ -47,6 +47,11 @@
 using namespace clang;
 using namespace CodeGen;
 
+// Experiment to make sanitizers easier to debug
+static llvm::cl::opt<bool> ClSanitizeDebugDeoptimization(
+    "sanitizer-de-opt-traps", llvm::cl::Optional,
+    llvm::cl::desc("Deoptimize traps for sanitizers"), llvm::cl::init(false));
+
 //===--------------------------------------------------------------------===//
 //                        Miscellaneous Helper Methods
 //===--------------------------------------------------------------------===//
@@ -3576,7 +3581,8 @@
     TrapBBs.resize(CheckHandlerID + 1);
   llvm::BasicBlock *&TrapBB = TrapBBs[CheckHandlerID];
 
-  if (!CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) {
+  if (ClSanitizeDebugDeoptimization ||
+      !CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) {
     TrapBB = createBasicBlock("trap");
     Builder.CreateCondBr(Checked, Cont, TrapBB);
     EmitBlock(TrapBB);
@@ -3590,6 +3596,8 @@
                                     CGM.getCodeGenOpts().TrapFuncName);
       TrapCall->addFnAttr(A);
     }
+    if (ClSanitizeDebugDeoptimization)
+      TrapCall->addFnAttr(llvm::Attribute::NoMerge);
     TrapCall->setDoesNotReturn();
     TrapCall->setDoesNotThrow();
     Builder.CreateUnreachable();
Index: llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
+++ llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
@@ -39,6 +39,11 @@
 static cl::opt<bool> SingleTrapBB("bounds-checking-single-trap",
                                   cl::desc("Use one trap block per function"));
 
+// Experiment to make sanitizers easier to debug
+static llvm::cl::opt<bool> ClBoundsSanitizeDebugDeoptimization(
+    "bounds-de-opt-traps", llvm::cl::Optional,
+    llvm::cl::desc("Deoptimize traps for sanitizers"), llvm::cl::init(false));
+
 STATISTIC(ChecksAdded, "Bounds checks added");
 STATISTIC(ChecksSkipped, "Bounds checks skipped");
 STATISTIC(ChecksUnable, "Bounds checks unable to add");
@@ -181,7 +186,7 @@
   // will create a fresh block every time it is called.
   BasicBlock *TrapBB = nullptr;
   auto GetTrapBB = [&TrapBB](BuilderTy &IRB) {
-    if (TrapBB && SingleTrapBB)
+    if (!ClBoundsSanitizeDebugDeoptimization && TrapBB && SingleTrapBB)
       return TrapBB;
 
     Function *Fn = IRB.GetInsertBlock()->getParent();
@@ -194,6 +199,8 @@
 
     auto *F = Intrinsic::getDeclaration(Fn->getParent(), Intrinsic::trap);
     CallInst *TrapCall = IRB.CreateCall(F, {});
+    if (ClBoundsSanitizeDebugDeoptimization)
+      TrapCall->addFnAttr(llvm::Attribute::NoMerge);
     TrapCall->setDoesNotReturn();
     TrapCall->setDoesNotThrow();
     TrapCall->setDebugLoc(DebugLoc);


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