[Darwin] Use errorHandler from liblldCommon

Summary:
Error handling in liblldCore and the Darwin toolchain prints to an
output stream. A TODO in the project explained that a diagnostics
interface resembling Clang's should be added.

For now, the simple diagnostics interface defined in liblldCommon seems
like an improvement. It prints colors when they're available, uses locks
for thread-safety, and abstracts away the `"error: "` and newline
literal strings that litter the Darwin toolchain code.

To use the liblldCommon error handler, a link dependency is added to
the liblldDriver library.

Test Plan:
1. check-lld
2. Invoke `ld64.lld -r` in a terminal that supports color output.
   Confirm that "ld64.lld: error: -arch not specified and could not be inferred"
   is output, and that the "error:" is colored red!

Reviewers: ruiu, smeenai

Reviewed By: ruiu

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D47998

llvm-svn: 334466

1 files changed, 2 insertions, 2 deletions

diff --git a/lld/lib/Core/LinkingContext.cpp b/lld/lib/Core/LinkingContext.cpp
index 5de863aa7f3..0f225c32212 100644
--- a/lld/lib/Core/LinkingContext.cpp
+++ b/lld/lib/Core/LinkingContext.cpp
@@ -20,8 +20,8 @@ LinkingContext::LinkingContext() = default;
 
 LinkingContext::~LinkingContext() = default;
 
-bool LinkingContext::validate(raw_ostream &diagnostics) {
-  return validateImpl(diagnostics);
+bool LinkingContext::validate() {
+  return validateImpl();
 }
 
 llvm::Error LinkingContext::writeFile(const File &linkedFile) const {