[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

4 files changed, 5 insertions, 9 deletions

diff --git a/lld/include/lld/Common/Driver.h b/lld/include/lld/Common/Driver.h
index 15ec3cd44cb..f6d92933af6 100644
--- a/lld/include/lld/Common/Driver.h
+++ b/lld/include/lld/Common/Driver.h
@@ -30,7 +30,7 @@ bool link(llvm::ArrayRef<const char *> Args, bool CanExitEarly,
 }
 
 namespace mach_o {
-bool link(llvm::ArrayRef<const char *> Args,
+bool link(llvm::ArrayRef<const char *> Args, bool CanExitEarly,
           llvm::raw_ostream &Diag = llvm::errs());
 }
 
diff --git a/lld/include/lld/Core/LinkingContext.h b/lld/include/lld/Core/LinkingContext.h
index 6dffdd4efe7..52ab1a2480e 100644
--- a/lld/include/lld/Core/LinkingContext.h
+++ b/lld/include/lld/Core/LinkingContext.h
@@ -16,7 +16,6 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Error.h"
-#include "llvm/Support/raw_ostream.h"
 #include <cassert>
 #include <cstdint>
 #include <memory>
@@ -167,10 +166,10 @@ public:
   /// After all set* methods are called, the Driver calls this method
   /// to validate that there are no missing options or invalid combinations
   /// of options.  If there is a problem, a description of the problem
-  /// is written to the supplied stream.
+  /// is written to the global error handler.
   ///
   /// \returns true if there is an error with the current settings.
-  bool validate(raw_ostream &diagnostics);
+  bool validate();
 
   /// Formats symbol name for use in error messages.
   virtual std::string demangle(StringRef symbolName) const = 0;
@@ -250,7 +249,7 @@ protected:
 
 private:
   /// Validate the subclass bits. Only called by validate.
-  virtual bool validateImpl(raw_ostream &diagnostics) = 0;
+  virtual bool validateImpl() = 0;
 };
 
 } // end namespace lld
diff --git a/lld/include/lld/Core/TODO.txt b/lld/include/lld/Core/TODO.txt
index 8b523045de7..2aa61ff8612 100644
--- a/lld/include/lld/Core/TODO.txt
+++ b/lld/include/lld/Core/TODO.txt
@@ -6,9 +6,6 @@ include/lld/Core
   abstraction only works for returning low level OS errors.  It does not
   work for describing formatting issues.
 
-* We need to design a diagnostics interface.  It would be nice to share code
-  with Clang_ where possible.
-
 * We need to add more attributes to File.  In particular, we need cpu
   and OS information (like target triples).  We should also provide explicit
   support for `LLVM IR module flags metadata`__.
diff --git a/lld/include/lld/ReaderWriter/MachOLinkingContext.h b/lld/include/lld/ReaderWriter/MachOLinkingContext.h
index 5f9588d7208..fde65880c3e 100644
--- a/lld/include/lld/ReaderWriter/MachOLinkingContext.h
+++ b/lld/include/lld/ReaderWriter/MachOLinkingContext.h
@@ -89,7 +89,7 @@ public:
                  bool exportDynamicSymbols);
 
   void addPasses(PassManager &pm) override;
-  bool validateImpl(raw_ostream &diagnostics) override;
+  bool validateImpl() override;
   std::string demangle(StringRef symbolName) const override;
 
   void createImplicitFiles(std::vector<std::unique_ptr<File>> &) override;