[cfe-commits] PATCH: Add diagnostic output for crash reports

[Douglas Gregor]

Hi Chad,

On Jul 13, 2011, at 2:07 PM, Chad Rosier wrote:

> This patch adds support for producing additional diagnostic information upon a clang crash.  Specifically, the compile is rerun to generate preprocessed source and a message is emitted showing all the command-line options needed to reproduce the problem.  The user is asked to submit a radar/bug report and attach this additional information.  Also, I tested things by hard coding the verifier pass to fail, but I was hoping someone could suggest a more robust means of testing prior to committing.

Making Clang crash for testing purposes is *easy* :)

#pragma clang __debug crash 

> This is for <rdar://problem/9575623>.


Thanks for working on this! Some comments:

Index: include/clang/Driver/Compilation.h
===================================================================
--- include/clang/Driver/Compilation.h	(revision 135078)
+++ include/clang/Driver/Compilation.h	(working copy)
@@ -14,6 +14,7 @@
 #include "clang/Driver/Util.h"
 
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/Support/Path.h"
 
 namespace llvm {
   class raw_ostream;
@@ -60,6 +61,9 @@
   /// Result files which should be removed on failure.
   ArgStringList ResultFiles;
 
+  /// Redirection for stdout, stderr, etc.
+  const llvm::sys::Path **Redirects;
+
 public:
   Compilation(const Driver &D, const ToolChain &DefaultToolChain,
               InputArgList *Args, DerivedArgList *TranslatedArgs);
@@ -84,7 +88,7 @@
   const ArgStringList &getTempFiles() const { return TempFiles; }
 
   const ArgStringList &getResultFiles() const { return ResultFiles; }
-
+  
   /// getArgsForToolChain - Return the derived argument list for the
   /// tool chain \arg TC (or the default tool chain, if TC is not
   /// specified).
@@ -136,6 +140,11 @@
   /// Command which failed.
   /// \return The accumulated result code of the job.
   int ExecuteJob(const Job &J, const Command *&FailingCommand) const;
+
+  /// initCompilationForDiagnostics - Remove stale state and supress output
+  /// so compilation can be reexecuted to generate additional diagnostic
+  /// information (e.g., preprocessed source).

Typo "supress".

-int Driver::ExecuteCompilation(const Compilation &C) const {
+// When clang crashes, produce diagnostic information including the fully 
+// preprocessed source file and relevant command line arguments.  Request  
+// that the developer attach the diagnostic information to a radar.
+void Driver::generateCompilationDiagnostics(Compilation &C,
+                                            const Command *FailingCommand) {
+  llvm::errs() << "\nCompilation error detected, generating diagnostic "
+               << "information including preprocessed source code and "
+               << "relevant command line arguments.  Please submit a "
+               << "radar/bugzilla and include all diagnostic information.\n";

A few comments here.:

  - This should use the driver's diagnostics engine, rather than printing directly via llvm::errs()

  - The diagnostic emitted should be customized via something passed to "configure" so vendors of different Clang-based compilers can send people to different URLs to file bugs. The default llvm.org Clang should people to file a bug report at http://llvm.org/, but Apple/Google/whoever will want to customize that URL for the compilers they use.

Did you check how well this works when the crash occurs in a translation unit that uses a precompiled header? We'd like to make sure that we're actually going to get useful data in that case.

	- Doug