Support: Pass wrapped Error's error code through FileError

Change FileError to pass through the error code from the Error it wraps.
This allows APIs that return ECError to transition to FileError without
changing returned std::error_code.

This was extracted from https://reviews.llvm.org/D109345.

Differential Revision: https://reviews.llvm.org/D113225

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/unittests/Support/ErrorTest.cpp b/llvm/unittests/Support/ErrorTest.cpp
index 4d557cc..3ca94b2 100644
--- a/llvm/unittests/Support/ErrorTest.cpp
+++ b/llvm/unittests/Support/ErrorTest.cpp
@@ -963,6 +963,33 @@ TEST(Error, FileErrorTest) {
   });
 }
 
+TEST(Error, FileErrorErrorCode) {
+  for (std::error_code EC : {
+           make_error_code(std::errc::not_supported),
+           make_error_code(std::errc::invalid_argument),
+           make_error_code(std::errc::no_such_file_or_directory),
+       }) {
+    EXPECT_EQ(EC, errorToErrorCode(
+                      createFileError("file.bin", EC)));
+    EXPECT_EQ(EC, errorToErrorCode(
+                      createFileError("file.bin", /*Line=*/5, EC)));
+    EXPECT_EQ(EC, errorToErrorCode(
+                      createFileError("file.bin", errorCodeToError(EC))));
+    EXPECT_EQ(EC, errorToErrorCode(
+                      createFileError("file.bin", /*Line=*/5, errorCodeToError(EC))));
+  }
+
+  // inconvertibleErrorCode() should be wrapped to avoid a fatal error.
+  EXPECT_EQ(
+      "A file error occurred.",
+      errorToErrorCode(createFileError("file.bin", inconvertibleErrorCode()))
+          .message());
+  EXPECT_EQ(
+      "A file error occurred.",
+      errorToErrorCode(createFileError("file.bin", /*Line=*/5, inconvertibleErrorCode()))
+          .message());
+}
+
 enum class test_error_code {
   unspecified = 1,
   error_1,