[PATCH] D33151: ThinLTO: Verify bitcode before lauching the ThinLTOCodeGenerator.

[Adrian Prantl via Phabricator via llvm-commits]

aprantl created this revision.
Herald added subscribers: eraman, inglorion, Prazek, mehdi_amini.

This patch invokes the Verifier on each module after loading, analogously to what regular LTO is doing. Besides diagnosing malformed bitcode, this allows it to strip out invalid debug info from bitcode produced by older, more buggy versions of LLVM. The new code is pretty much the same as in LTOCodeGenerator.cpp.

rdar://problem/31233625


Repository:
  rL LLVM

https://reviews.llvm.org/D33151

Files:
  lib/LTO/ThinLTOCodeGenerator.cpp
  test/LTO/X86/strip-debug-info.ll


Index: test/LTO/X86/strip-debug-info.ll
===================================================================
--- test/LTO/X86/strip-debug-info.ll
+++ test/LTO/X86/strip-debug-info.ll
@@ -6,9 +6,19 @@
 ; RUN:     -o %t.o %S/Inputs/strip-debug-info.bc 2>&1 | \
 ; RUN:     FileCheck %s -allow-empty -check-prefix=CHECK-WARN
 ; RUN: llvm-nm %t.o | FileCheck %s 
+; RUN: not llvm-lto -thinlto -thinlto-action=run \
+; RUN:     -lto-strip-invalid-debug-info=false \
+; RUN:     %S/Inputs/strip-debug-info.bc 2>&1 | \
+; RUN:     FileCheck %s -allow-empty -check-prefix=CHECK-ERR
+; RUN: not llvm-lto -thinlto -thinlto-action=run \
+; RUN:     -lto-strip-invalid-debug-info=true \
+; RUN:     -exported-symbol foo -exported-symbol _foo \
+; RUN:     %S/Inputs/strip-debug-info.bc 2>&1 | \
+; RUN:     FileCheck %s -allow-empty -check-prefix=CHECK-WARN
 
 ; CHECK-ERR: Broken module found, compilation aborted
 ; CHECK-WARN: Invalid debug info found, debug info will be stripped
+; CHECK-WARN-NOT: Broken module found
 ; CHECK: foo
 define void @foo() {
   ret void
Index: lib/LTO/ThinLTOCodeGenerator.cpp
===================================================================
--- lib/LTO/ThinLTOCodeGenerator.cpp
+++ lib/LTO/ThinLTOCodeGenerator.cpp
@@ -25,9 +25,11 @@
 #include "llvm/Bitcode/BitcodeWriterPass.h"
 #include "llvm/ExecutionEngine/ObjectMemoryBuffer.h"
 #include "llvm/IR/DiagnosticPrinter.h"
+#include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Mangler.h"
+#include "llvm/IR/Verifier.h"
 #include "llvm/IRReader/IRReader.h"
 #include "llvm/LTO/LTO.h"
 #include "llvm/Linker/Linker.h"
@@ -62,6 +64,7 @@
 extern cl::opt<bool> LTODiscardValueNames;
 extern cl::opt<std::string> LTORemarksFilename;
 extern cl::opt<bool> LTOPassRemarksWithHotness;
+extern cl::opt<bool> LTOStripInvalidDebugInfo;
 }
 
 namespace {
@@ -142,6 +145,17 @@
     report_fatal_error("renameModuleForThinLTO failed");
 }
 
+namespace {
+class ThinLTODiagnosticInfo : public DiagnosticInfo {
+  const Twine &Msg;
+public:
+  ThinLTODiagnosticInfo(const Twine &DiagMsg,
+                        DiagnosticSeverity Severity = DS_Error)
+      : DiagnosticInfo(DK_Linker, Severity), Msg(DiagMsg) {}
+  void print(DiagnosticPrinter &DP) const override { DP << Msg; }
+};
+}
+
 static std::unique_ptr<Module>
 loadModuleFromBuffer(const MemoryBufferRef &Buffer, LLVMContext &Context,
                      bool Lazy, bool IsImporting) {
@@ -159,6 +173,17 @@
     });
     report_fatal_error("Can't load module, abort.");
   }
+
+  // Verify the module.
+  bool BrokenDebugInfo = false;
+  if (verifyModule(*ModuleOrErr.get(), &dbgs(),
+                   LTOStripInvalidDebugInfo ? &BrokenDebugInfo : nullptr))
+    report_fatal_error("Broken module found, compilation aborted!");
+  if (BrokenDebugInfo) {
+    Context.diagnose(ThinLTODiagnosticInfo(
+        "Invalid debug info found, debug info will be stripped", DS_Warning));
+    StripDebugInfo(*ModuleOrErr.get());
+  }
   return std::move(ModuleOrErr.get());
 }
 


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