From 7aa802198be543f6d5198c44e6402037a2ed9596 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@google.com>
Date: Wed, 1 Feb 2017 22:09:34 +0000
Subject: [PATCH] Return Error instead of bool from mergeTypeStreams().

Previously, mergeTypeStreams returns only true or false, so it was
impossible to know the reason if it failed. This patch changes the
function signature so that it returns an Error object.

Differential Revision: https://reviews.llvm.org/D29362

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293820 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../DebugInfo/CodeView/TypeStreamMerger.h     |  3 +-
 lib/DebugInfo/CodeView/TypeStreamMerger.cpp   | 38 ++++++++++---------
 2 files changed, 23 insertions(+), 18 deletions(-)

diff --git a/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h b/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h
index af396c79d07..3c915af1657 100644
--- a/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h
+++ b/include/llvm/DebugInfo/CodeView/TypeStreamMerger.h
@@ -13,12 +13,13 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/DebugInfo/CodeView/TypeTableBuilder.h"
+#include "llvm/Support/Error.h"
 
 namespace llvm {
 namespace codeview {
 
 /// Merges one type stream into another. Returns true on success.
-bool mergeTypeStreams(TypeTableBuilder &DestStream, const CVTypeArray &Types);
+Error mergeTypeStreams(TypeTableBuilder &DestStream, const CVTypeArray &Types);
 
 } // end namespace codeview
 } // end namespace llvm
diff --git a/lib/DebugInfo/CodeView/TypeStreamMerger.cpp b/lib/DebugInfo/CodeView/TypeStreamMerger.cpp
index ed6cf5743a1..07984ad2fe3 100644
--- a/lib/DebugInfo/CodeView/TypeStreamMerger.cpp
+++ b/lib/DebugInfo/CodeView/TypeStreamMerger.cpp
@@ -55,9 +55,7 @@ namespace {
 class TypeStreamMerger : public TypeVisitorCallbacks {
 public:
   TypeStreamMerger(TypeTableBuilder &DestStream)
-      : DestStream(DestStream), FieldListBuilder(DestStream) {
-    assert(!hadError());
-  }
+      : DestStream(DestStream), FieldListBuilder(DestStream) {}
 
 /// TypeVisitorCallbacks overrides.
 #define TYPE_RECORD(EnumName, EnumVal, Name)                                   \
@@ -74,12 +72,15 @@ public:
   Error visitTypeEnd(CVType &Record) override;
   Error visitMemberEnd(CVMemberRecord &Record) override;
 
-  bool mergeStream(const CVTypeArray &Types);
+  Error mergeStream(const CVTypeArray &Types);
 
 private:
   template <typename RecordType>
   Error visitKnownRecordImpl(RecordType &Record) {
-    FoundBadTypeIndex |= !Record.remapTypeIndices(IndexMap);
+    if (!Record.remapTypeIndices(IndexMap))
+      LastError = joinErrors(
+          std::move(*LastError),
+          llvm::make_error<CodeViewError>(cv_error_code::corrupt_record));
     IndexMap.push_back(DestStream.writeKnownType(Record));
     return Error::success();
   }
@@ -94,14 +95,15 @@ private:
 
   template <typename RecordType>
   Error visitKnownMemberRecordImpl(RecordType &Record) {
-    FoundBadTypeIndex |= !Record.remapTypeIndices(IndexMap);
+    if (!Record.remapTypeIndices(IndexMap))
+      LastError = joinErrors(
+          std::move(*LastError),
+          llvm::make_error<CodeViewError>(cv_error_code::corrupt_record));
     FieldListBuilder.writeMemberType(Record);
     return Error::success();
   }
 
-  bool hadError() { return FoundBadTypeIndex; }
-
-  bool FoundBadTypeIndex = false;
+  Optional<Error> LastError;
 
   BumpPtrAllocator Allocator;
 
@@ -163,9 +165,10 @@ Error TypeStreamMerger::visitUnknownType(CVType &Rec) {
   return llvm::make_error<CodeViewError>(cv_error_code::corrupt_record);
 }
 
-bool TypeStreamMerger::mergeStream(const CVTypeArray &Types) {
+Error TypeStreamMerger::mergeStream(const CVTypeArray &Types) {
   assert(IndexMap.empty());
   TypeVisitorCallbackPipeline Pipeline;
+  LastError = Error::success();
 
   TypeDeserializer Deserializer;
   Pipeline.addCallbackToPipeline(Deserializer);
@@ -173,15 +176,16 @@ bool TypeStreamMerger::mergeStream(const CVTypeArray &Types) {
 
   CVTypeVisitor Visitor(Pipeline);
 
-  if (auto EC = Visitor.visitTypeStream(Types)) {
-    consumeError(std::move(EC));
-    return false;
-  }
+  if (auto EC = Visitor.visitTypeStream(Types))
+    return EC;
   IndexMap.clear();
-  return !hadError();
+
+  Error Ret = std::move(*LastError);
+  LastError.reset();
+  return Ret;
 }
 
-bool llvm::codeview::mergeTypeStreams(TypeTableBuilder &DestStream,
-                                      const CVTypeArray &Types) {
+Error llvm::codeview::mergeTypeStreams(TypeTableBuilder &DestStream,
+                                       const CVTypeArray &Types) {
   return TypeStreamMerger(DestStream).mergeStream(Types);
 }
-- 
2.50.1