[Symbolize] Check if the PE file has a PDB and emit an error if we can't load it

Summary:
Previously we would try to load PDBs for every PE executable we tried to
symbolize. If that failed, we would fall back to DWARF. If there wasn't
any DWARF, we'd print mostly useless symbol information using the export
table.

With this change, we only try to load PDBs for executables that claim to
have them. If that fails, we can now print an error rather than falling
back silently. This should make it a lot easier to diagnose and fix
common symbolization issues, such as not having DIA or not having a PDB.

Reviewers: zturner, eugenis

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D20982

llvm-svn: 271725

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/tools/sancov/sancov.cc b/llvm/tools/sancov/sancov.cc
index efeb46a1faa..e4e83b0bbc8 100644
--- a/llvm/tools/sancov/sancov.cc
+++ b/llvm/tools/sancov/sancov.cc
@@ -135,6 +135,12 @@ template <typename T> static void FailIfError(const ErrorOr<T> &E) {
   FailIfError(E.getError());
 }
 
+template <typename T> static void FailIfError(Expected<T> &E) {
+  if (E)
+    return;
+  logAllUnhandledErrors(E.takeError(), errs(), "Error: ");
+}
+
 static void FailIfNotEmpty(const llvm::Twine &E) {
   if (E.str().empty())
     return;