[llc] New diagnostic handler

Without a diagnostic handler installed, llc's behaviour is to exit on the first
error that it encounters. This is very different from the behaviour of clang
and other front ends, which try to gather as many errors as possible before
exiting.

This commit adds a diagnostic handler to llc, allowing it to find and report
more than one error. The old behaviour is preserved under a flag (-exit-on-error).

Some of the tests fail with the new diagnostic handler, so they have to use the
new flag in order to run under the previous behaviour. Some of these are known
bugs, others need further investigation. Ideally, we should fix the tests and
remove the flag at some point in the future.

Reapplied after fixing the LLDB build that was broken due to the new
DiagnosticSeverity in LLVMContext.h, and fixed an UB in the new change.

Patch by Diana Picus.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@269655 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/IR/LLVMContext.cpp b/lib/IR/LLVMContext.cpp
index 9369cbd6a08..9f8680cf6c0 100644
--- a/lib/IR/LLVMContext.cpp
+++ b/lib/IR/LLVMContext.cpp
@@ -231,7 +231,8 @@ static bool isDiagnosticEnabled(const DiagnosticInfo &DI) {
   return true;
 }
 
-static const char *getDiagnosticMessagePrefix(DiagnosticSeverity Severity) {
+const char *
+LLVMContext::getDiagnosticMessagePrefix(DiagnosticSeverity Severity) {
   switch (Severity) {
   case DS_Error:
     return "error";