[clang-tools-extra] [clang-doc] Remove uses of consumeError (PR #168759)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang-tools-extra

Author: Paul Kirth (ilovepi)

<details>
<summary>Changes</summary>

In BitcodeReader, we were using consumeError(), which drops the error
and hides it from normal usage. To avoid that, we can just slightly
tweak the API to return an Expected<T>, and propagate the error
accordingly.

---
Full diff: https://github.com/llvm/llvm-project/pull/168759.diff


2 Files Affected:

- (modified) clang-tools-extra/clang-doc/BitcodeReader.cpp (+20-26) 
- (modified) clang-tools-extra/clang-doc/BitcodeReader.h (+1-1) 


``````````diff
diff --git a/clang-tools-extra/clang-doc/BitcodeReader.cpp b/clang-tools-extra/clang-doc/BitcodeReader.cpp
index 4efbbd34730cf..0af7aeb1d3500 100644
--- a/clang-tools-extra/clang-doc/BitcodeReader.cpp
+++ b/clang-tools-extra/clang-doc/BitcodeReader.cpp
@@ -847,9 +847,11 @@ llvm::Error ClangDocBitcodeReader::readBlock(unsigned ID, T I) {
 
   while (true) {
     unsigned BlockOrCode = 0;
-    Cursor Res = skipUntilRecordOrBlock(BlockOrCode);
+    llvm::Expected<Cursor> C = skipUntilRecordOrBlock(BlockOrCode);
+    if (!C)
+      return C.takeError();
 
-    switch (Res) {
+    switch (*C) {
     case Cursor::BadBlock:
       return llvm::createStringError(llvm::inconvertibleErrorCode(),
                                      "bad block found");
@@ -985,45 +987,39 @@ llvm::Error ClangDocBitcodeReader::readSubBlock(unsigned ID, T I) {
   }
 }
 
-ClangDocBitcodeReader::Cursor
+llvm::Expected<ClangDocBitcodeReader::Cursor>
 ClangDocBitcodeReader::skipUntilRecordOrBlock(unsigned &BlockOrRecordID) {
   llvm::TimeTraceScope("Reducing infos", "skipUntilRecordOrBlock");
   BlockOrRecordID = 0;
 
   while (!Stream.AtEndOfStream()) {
-    Expected<unsigned> MaybeCode = Stream.ReadCode();
-    if (!MaybeCode) {
-      // FIXME this drops the error on the floor.
-      consumeError(MaybeCode.takeError());
-      return Cursor::BadBlock;
-    }
+    Expected<unsigned> Code = Stream.ReadCode();
+    if (!Code)
+      return Code.takeError();
 
-    unsigned Code = MaybeCode.get();
-    if (Code >= static_cast<unsigned>(llvm::bitc::FIRST_APPLICATION_ABBREV)) {
+    if (*Code >= static_cast<unsigned>(llvm::bitc::FIRST_APPLICATION_ABBREV)) {
       BlockOrRecordID = Code;
       return Cursor::Record;
     }
-    switch (static_cast<llvm::bitc::FixedAbbrevIDs>(Code)) {
+    switch (static_cast<llvm::bitc::FixedAbbrevIDs>(*Code)) {
     case llvm::bitc::ENTER_SUBBLOCK:
       if (Expected<unsigned> MaybeID = Stream.ReadSubBlockID())
         BlockOrRecordID = MaybeID.get();
-      else {
-        // FIXME this drops the error on the floor.
-        consumeError(MaybeID.takeError());
-      }
+      else
+        return MaybeID.takeError();
       return Cursor::BlockBegin;
     case llvm::bitc::END_BLOCK:
       if (Stream.ReadBlockEnd())
-        return Cursor::BadBlock;
+        return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                       "error at end of block");
       return Cursor::BlockEnd;
     case llvm::bitc::DEFINE_ABBREV:
-      if (llvm::Error Err = Stream.ReadAbbrevRecord()) {
-        // FIXME this drops the error on the floor.
-        consumeError(std::move(Err));
-      }
+      if (llvm::Error Err = Stream.ReadAbbrevRecord())
+        return std::move(Err);
       continue;
     case llvm::bitc::UNABBREV_RECORD:
-      return Cursor::BadBlock;
+      return llvm::createStringError(llvm::inconvertibleErrorCode(),
+                                     "found unabbreviated record");
     case llvm::bitc::FIRST_APPLICATION_ABBREV:
       llvm_unreachable("Unexpected abbrev id.");
     }
@@ -1149,10 +1145,8 @@ ClangDocBitcodeReader::readBitcode() {
         return std::move(Err);
       continue;
     default:
-      if (llvm::Error Err = Stream.SkipBlock()) {
-        // FIXME this drops the error on the floor.
-        consumeError(std::move(Err));
-      }
+      if (llvm::Error Err = Stream.SkipBlock())
+        return std::move(Err);
       continue;
     }
   }
diff --git a/clang-tools-extra/clang-doc/BitcodeReader.h b/clang-tools-extra/clang-doc/BitcodeReader.h
index 4947721f0a06d..0f7f4f256f15b 100644
--- a/clang-tools-extra/clang-doc/BitcodeReader.h
+++ b/clang-tools-extra/clang-doc/BitcodeReader.h
@@ -59,7 +59,7 @@ class ClangDocBitcodeReader {
 
   // Helper function to step through blocks to find and dispatch the next record
   // or block to be read.
-  Cursor skipUntilRecordOrBlock(unsigned &BlockOrRecordID);
+  llvm::Expected<Cursor> skipUntilRecordOrBlock(unsigned &BlockOrRecordID);
 
   // Helper function to set up the appropriate type of Info.
   llvm::Expected<std::unique_ptr<Info>> readBlockToInfo(unsigned ID);

``````````

</details>


https://github.com/llvm/llvm-project/pull/168759