[Driver] Don't preprocess source files when reproducing linker crashes

[abrachet]

Summary

It's not necessary to redo the source file preprocessing for reproducing linker
crashes because we must have successfully created the object file by this point.
Skip this step, and also don't report the preprocessed source file or create
the clang invocation shell script. The latter is no longer sensible without the
preprocessed source, or helpful given the linker reproducer will have it's own
shell script.

[thakis]

Thanks!

clang/lib/Driver/Driver.cpp

if (!CrashFilePath.empty()) {
     if (EC)
       return false;
     return true;
   }
 
   return false;
 }
 
+static const char BugReporMsg[] =
+    "\n********************\n\n"
+    "PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:\n"
+    "Preprocessed source(s) and associated run script(s) are located at:";
+
 // When clang crashes, produce diagnostic information including the fully
 // preprocessed source file(s).  Request that the developer attach the
 // diagnostic information to a bug report.
 void Driver::generateCompilationDiagnostics(
     Compilation &C, const Command &FailingCommand,
     StringRef AdditionalInformation, CompilationDiagnosticReport *Report) {
   if (C.getArgs().hasArg(options::OPT_fno_crash_diagnostics))
     return;
void Driver::generateCompilationDiagnostics(
 
   // Keep track of whether we produce any errors while trying to produce
   // preprocessed sources.
   DiagnosticErrorTrap Trap(Diags);
 
   // Suppress tool output.
   C.initCompilationForDiagnostics();
 
+  // If lld failed, rerun it again with --reproduce.
+  if (IsLLD) {
+    const char *TmpName = CreateTempFile(C, "linker-crash", "tar");
+    Command NewLLDInvocation = Cmd;
+    llvm::opt::ArgStringList ArgList = NewLLDInvocation.getArguments();
+    StringRef ReproduceOption =
+        C.getDefaultToolChain().getTriple().isWindowsMSVCEnvironment()
+            ? "/reproduce:"
+            : "--reproduce=";
+    ArgList.push_back(Saver.save(Twine(ReproduceOption) + TmpName).data());
+    NewLLDInvocation.replaceArguments(std::move(ArgList));
+
+    // Redirect stdout/stderr to /dev/null.
+    NewLLDInvocation.Execute({None, {""}, {""}}, nullptr, nullptr);
+    Diag(clang::diag::note_drv_command_failed_diag_msg) << BugReporMsg;
+    Diag(clang::diag::note_drv_command_failed_diag_msg) << TmpName;
+    Diag(clang::diag::note_drv_command_failed_diag_msg)
+        << "\n\n********************";
+    if (Report)
+      Report->TemporaryFiles.push_back(TmpName);
+    return;
+  }
+
   // Construct the list of inputs.
   InputList Inputs;
   BuildInputs(C.getDefaultToolChain(), C.getArgs(), Inputs);
 
   for (InputList::iterator it = Inputs.begin(), ie = Inputs.end(); it != ie;) {
     bool IgnoreInput = false;
 
     // Ignore input from stdin or any inputs that cannot be preprocessed.
void Driver::generateCompilationDiagnostics(
 
   // If any of the preprocessing commands failed, clean up and exit.
   if (!FailingCommands.empty()) {
     Diag(clang::diag::note_drv_command_failed_diag_msg)
         << "Error generating preprocessed source(s).";
     return;
   }
 
-  // If lld failed, rerun it again with --reproduce.
-  if (IsLLD) {
-    const char *TmpName = CreateTempFile(C, "linker-crash", "tar");
-    Command NewLLDInvocation = Cmd;
-    llvm::opt::ArgStringList ArgList = NewLLDInvocation.getArguments();
-    StringRef ReproduceOption =
-        C.getDefaultToolChain().getTriple().isWindowsMSVCEnvironment()
-            ? "/reproduce:"
-            : "--reproduce=";
-    ArgList.push_back(Saver.save(Twine(ReproduceOption) + TmpName).data());
-    NewLLDInvocation.replaceArguments(std::move(ArgList));
-
-    // Redirect stdout/stderr to /dev/null.
-    NewLLDInvocation.Execute({None, {""}, {""}}, nullptr, nullptr);
-  }
-
   const ArgStringList &TempFiles = C.getTempFiles();
   if (TempFiles.empty()) {
     Diag(clang::diag::note_drv_command_failed_diag_msg)
         << "Error generating preprocessed source(s).";
     return;
   }
 
-  Diag(clang::diag::note_drv_command_failed_diag_msg)
-      << "\n********************\n\n"
-         "PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:\n"
-         "Preprocessed source(s) and associated run script(s) are located at:";
+  Diag(clang::diag::note_drv_command_failed_diag_msg) << BugReporMsg;
 
   SmallString<128> VFS;
   SmallString<128> ReproCrashFilename;
   for (const char *TempFile : TempFiles) {
     Diag(clang::diag::note_drv_command_failed_diag_msg) << TempFile;
     if (Report)
       Report->TemporaryFiles.push_back(TempFile);
     if (ReproCrashFilename.empty()) {

clang/test/Driver/lld-repro.c

 // REQUIRES: lld
 // UNSUPPORTED: ps4, ps5
 
-// RUN: not %clang %s -nostartfiles -nostdlib -fuse-ld=lld -gen-reproducer=error -fcrash-diagnostics-dir=%t -fcrash-diagnostics=all 2>&1 \
+// RUN: echo "-nostartfiles -nostdlib -fuse-ld=lld -gen-reproducer=error -fcrash-diagnostics-dir=%t" \
+// RUN:   | sed -e 's/\\/\\\\/g' > %t.rsp
+
+// RUN: not %clang %s @%t.rsp -fcrash-diagnostics=all 2>&1 \
+// RUN:   | FileCheck %s
+
+// Test that the reproducer can still be created even when the input source cannot be preprocessed
+// again, like when reading from stdin.
+// RUN: not %clang -x c - @%t.rsp -fcrash-diagnostics=all 2>&1 < %s \
 // RUN:   | FileCheck %s
 
 // check that we still get lld's output
 // CHECK: error: undefined symbol: {{_?}}a
 
 // CHECK: Preprocessed source(s) and associated run script(s) are located at:
-// CHECK-NEXT: note: diagnostic msg: {{.*}}lld-repro-{{.*}}.c
 // CHECK-NEXT: note: diagnostic msg: {{.*}}linker-crash-{{.*}}.tar
-// CHECK-NEXT: note: diagnostic msg: {{.*}}lld-repro-{{.*}}.sh
 // CHECK-NEXT: note: diagnostic msg:
 // CHECK: ********************
 
-// RUN: not %clang %s -nostartfiles -nostdlib -fuse-ld=lld -gen-reproducer=error -fcrash-diagnostics-dir=%t -fcrash-diagnostics=compiler 2>&1 \
+// RUN: not %clang %s @%t.rsp -fcrash-diagnostics=compiler 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=NO-LINKER
-// RUN: not %clang %s -nostartfiles -nostdlib -fuse-ld=lld -gen-reproducer=error -fcrash-diagnostics-dir=%t 2>&1 \
+// RUN: not %clang %s @%t.rsp 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=NO-LINKER
 
 // NO-LINKER-NOT: Preprocessed source(s) and associated run script(s) are located at:
 
 extern int a;
 int main() {
   return a;
 }