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

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.

Differential Revision: https://reviews.llvm.org/D137289

Author: abrachet

clang/lib/Driver/Driver.cpp

@@ -1527,6 +1527,11 @@ bool Driver::getCrashDiagnosticFile(StringRef ReproCrashFilename,
   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.
@@ -1582,6 +1587,29 @@ void Driver::generateCompilationDiagnostics(
   // 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);
@@ -1659,33 +1687,14 @@ void Driver::generateCompilationDiagnostics(
     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;

clang/test/Driver/lld-repro.c

@@ -1,22 +1,28 @@
 // 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: