[clang] Allow custom bug report messages

Clang vendors may need to set a custom message for bug reports if the
default is not sufficient (e.g. if they need the user to provide more
information than what the default message asks for). This can be
configured using the new macro `CLANG_CUSTOM_BUG_REPORT_MSG`.

Author: alanzhao1

clang/include/clang/Config/config.h.cmake

@@ -85,4 +85,7 @@
 /* Whether CIR is built into Clang */
 #cmakedefine01 CLANG_ENABLE_CIR
 
+/* Define if there is a custom bug report message */
+#cmakedefine CLANG_CUSTOM_BUG_REPORT_MSG "${CLANG_CUSTOM_BUG_REPORT_MSG}"
+
 #endif

clang/tools/driver/driver.cpp

@@ -235,9 +235,13 @@ static int ExecuteCC1Tool(SmallVectorImpl<const char *> &ArgV,
 
 int clang_main(int Argc, char **Argv, const llvm::ToolContext &ToolContext) {
   noteBottomOfStack();
+  #ifdef CLANG_CUSTOM_BUG_REPORT_MSG
+  llvm::setBugReportMsg(CLANG_CUSTOM_BUG_REPORT_MSG);
+  #else
   llvm::setBugReportMsg("PLEASE submit a bug report to " BUG_REPORT_URL
                         " and include the crash backtrace, preprocessed "
                         "source, and associated run script.\n");
+  #endif
   SmallVector<const char *, 256> Args(Argv, Argv + Argc);
 
   if (llvm::sys::Process::FixupStandardFileDescriptors())