[Support] Make all Errors convertible to std::error_code.

This is a temporary crutch to enable code that currently uses std::error_code
to be incrementally moved over to Error. Requiring all Error instances be
convertible enables clients to call errorToErrorCode on any error (not just
ECErrors created by conversion *from* an error_code).

This patch also moves code for Error from ErrorHandling.cpp into a new
Error.cpp file.

llvm-svn: 264221

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/unittests/Support/ErrorTest.cpp b/llvm/unittests/Support/ErrorTest.cpp
index 788dcd3..1807547 100644
--- a/llvm/unittests/Support/ErrorTest.cpp
+++ b/llvm/unittests/Support/ErrorTest.cpp
@@ -9,6 +9,7 @@
 
 #include "llvm/Support/Error.h"
 #include "llvm/Support/Errc.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "gtest/gtest.h"
 #include <memory>
 
@@ -30,6 +31,10 @@ public:
     OS << "CustomError { " << getInfo() << "}";
   }
 
+  std::error_code convertToErrorCode() const override {
+    llvm_unreachable("CustomError doesn't support ECError conversion");
+  }
+
 protected:
   // This error is subclassed below, but we can't use inheriting constructors
   // yet, so we can't propagate the constructors through ErrorInfo. Instead
@@ -57,6 +62,10 @@ public:
     OS << "CustomSubError { " << getInfo() << ", " << getExtraInfo() << "}";
   }
 
+  std::error_code convertToErrorCode() const override {
+    llvm_unreachable("CustomSubError doesn't support ECError conversion");
+  }
+
 protected:
   int ExtraInfo;
 };