[llvm-readobj/libObject] - Introduce a custom warning handler for `ELFFile<ELFT>` methods.

Currently, we have a code duplication in llvm-readobj which was introduced in D63266.
The duplication was introduced to allow llvm-readobj to dump the partially
broken object. Methods in ELFFile<ELFT> perform a strict validation of the inputs,
what is itself good, but not for dumper tools, that might want to dump the information,
even if some pieces are broken/unexpected.

This patch introduces a warning handler which can be passed to ELFFile<ELFT> methods
and can allow skipping the non-critical errors when needed/possible.

For demonstration, I removed the duplication from llvm-readobj and implemented a warning using
the new custom warning handler. It also deduplicates the strings printed, making the output less verbose.

Differential revision: https://reviews.llvm.org/D65515

llvm-svn: 368260

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/tools/llvm-readobj/llvm-readobj.cpp b/llvm/tools/llvm-readobj/llvm-readobj.cpp
index bb629c28cf1..f607490e8f8 100644
--- a/llvm/tools/llvm-readobj/llvm-readobj.cpp
+++ b/llvm/tools/llvm-readobj/llvm-readobj.cpp
@@ -394,6 +394,12 @@ void reportWarning(Twine Msg) {
   WithColor::warning(errs()) << Msg << "\n";
 }
 
+void reportWarning(StringRef Input, Error Err) {
+  if (Input == "-")
+    Input = "<stdin>";
+  warn(createFileError(Input, std::move(Err)));
+}
+
 void warn(Error Err) {
   handleAllErrors(std::move(Err), [&](const ErrorInfoBase &EI) {
     reportWarning(EI.message());