From c6c6c7b177e2c42fb67bc5a215aa1f181a40ca5c Mon Sep 17 00:00:00 2001 From: David Blaikie Date: Tue, 7 Oct 2014 22:59:46 +0000 Subject: DebugInfo+DFSan: Ensure that debug info references to llvm::Functions remain pointing to the underlying function when wrappers are created This is somewhat the inverse of how similar bugs in DAE and ArgPromo manifested and were addressed. In those passes, individual call sites were visited explicitly, and then the old function was deleted. This left the debug info with a null llvm::Function* that needed to be updated to point to the new function. In the case of DFSan, it RAUWs the old function with the wrapper, which includes debug info. So now the debug info refers to the wrapper, which doesn't actually have any instructions with debug info in it, so it is ignored entirely - resulting in a DW_TAG_subprogram with no high/low pc, etc. Instead, fix up the debug info to refer to the original function after the RAUW messed it up. Reviewed/discussed with Peter Collingbourne on the llvm-dev mailing list. llvm-svn: 219249 --- llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp') diff --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp index 446bcf7..cb84fd6 100644 --- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp +++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp @@ -51,6 +51,7 @@ #include "llvm/ADT/StringExtras.h" #include "llvm/Analysis/ValueTracking.h" #include "llvm/IR/Dominators.h" +#include "llvm/IR/DebugInfo.h" #include "llvm/IR/IRBuilder.h" #include "llvm/IR/InlineAsm.h" #include "llvm/IR/InstVisitor.h" @@ -243,6 +244,7 @@ class DataFlowSanitizer : public ModulePass { DFSanABIList ABIList; DenseMap UnwrappedFnMap; AttributeSet ReadOnlyNoneAttrs; + DenseMap FunctionDIs; Value *getShadowAddress(Value *Addr, Instruction *Pos); bool isInstrumented(const Function *F); @@ -573,6 +575,8 @@ bool DataFlowSanitizer::runOnModule(Module &M) { if (ABIList.isIn(M, "skip")) return false; + FunctionDIs = makeSubprogramMap(M); + if (!GetArgTLSPtr) { Type *ArgTLSTy = ArrayType::get(ShadowTy, 64); ArgTLS = Mod->getOrInsertGlobal("__dfsan_arg_tls", ArgTLSTy); @@ -725,6 +729,12 @@ bool DataFlowSanitizer::runOnModule(Module &M) { Value *WrappedFnCst = ConstantExpr::getBitCast(NewF, PointerType::getUnqual(FT)); F.replaceAllUsesWith(WrappedFnCst); + + // Patch the pointer to LLVM function in debug info descriptor. + auto DI = FunctionDIs.find(&F); + if (DI != FunctionDIs.end()) + DI->second.replaceFunction(&F); + UnwrappedFnMap[WrappedFnCst] = &F; *i = NewF; -- cgit v1.1