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Bitstream reader: Fix undefined behavior seen after rL364464 

Summary:
After rL364464 the following tests started to fail when
running the clang-doc tests with an ubsan instrumented
build of clang-doc:
    Clang Tools :: clang-doc/single-file-public.cpp
    Extra Tools Unit Tests :: clang-doc/./ClangDocTests/BitcodeTest.emitEnumInfoBitcode
    Extra Tools Unit Tests :: clang-doc/./ClangDocTests/BitcodeTest.emitMethodInfoBitcode
    Extra Tools Unit Tests :: clang-doc/./ClangDocTests/BitcodeTest.emitRecordInfoBitcode
    Extra Tools Unit Tests :: clang-doc/./ClangDocTests/SerializeTest.emitInfoWithCommentBitcode

We need to check that the read value is in range for being
casted to the llvm::bitc::FixedAbbrevIDs enum, before the
cast in ClangDocBitcodeReader::skipUntilRecordOrBlock.

SerializedDiagnosticReader::skipUntilRecordOrBlock was updated
in the same way.

Reviewers: jfb

Reviewed By: jfb

Subscribers: Bigcheese, vsapsai, bruno, ilya-biryukov, dexonsmith, kadircet, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64262

llvm-svn: 365239
This commit is contained in:
Bjorn Pettersson 2019-07-05 20:22:40 +00:00
parent 28e0187175
commit 009225374a
2 changed files with 16 additions and 12 deletions
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15
clang-tools-extra/clang-doc/BitcodeReader.cpp
View File

@ -615,10 +615,12 @@ ClangDocBitcodeReader::skipUntilRecordOrBlock(unsigned &BlockOrRecordID) {
return Cursor::BadBlock;
}
// FIXME check that the enum is in range.
auto Code = static_cast<llvm::bitc::FixedAbbrevIDs>(MaybeCode.get());
switch (Code) {
unsigned Code = MaybeCode.get();
if (Code >= static_cast<unsigned>(llvm::bitc::FIRST_APPLICATION_ABBREV)) {
BlockOrRecordID = Code;
return Cursor::Record;
}
switch (static_cast<llvm::bitc::FixedAbbrevIDs>(Code)) {
case llvm::bitc::ENTER_SUBBLOCK:
if (Expected<unsigned> MaybeID = Stream.ReadSubBlockID())
BlockOrRecordID = MaybeID.get();
@ -639,9 +641,8 @@ ClangDocBitcodeReader::skipUntilRecordOrBlock(unsigned &BlockOrRecordID) {
continue;
case llvm::bitc::UNABBREV_RECORD:
return Cursor::BadBlock;
default:
BlockOrRecordID = Code;
return Cursor::Record;
case llvm::bitc::FIRST_APPLICATION_ABBREV:
llvm_unreachable("Unexpected abbrev id.");
}
}
llvm_unreachable("Premature stream end.");

13
clang/lib/Frontend/SerializedDiagnosticReader.cpp
View File

@ -124,7 +124,12 @@ SerializedDiagnosticReader::skipUntilRecordOrBlock(
else
return llvm::errorToErrorCode(Res.takeError());
switch ((llvm::bitc::FixedAbbrevIDs)Code) {
if (Code >= static_cast<unsigned>(llvm::bitc::FIRST_APPLICATION_ABBREV)) {
// We found a record.
BlockOrRecordID = Code;
return Cursor::Record;
}
switch (static_cast<llvm::bitc::FixedAbbrevIDs>(Code)) {
case llvm::bitc::ENTER_SUBBLOCK:
if (Expected<unsigned> Res = Stream.ReadSubBlockID())
BlockOrRecordID = Res.get();
@ -145,10 +150,8 @@ SerializedDiagnosticReader::skipUntilRecordOrBlock(
case llvm::bitc::UNABBREV_RECORD:
return SDError::UnsupportedConstruct;
default:
// We found a record.
BlockOrRecordID = Code;
return Cursor::Record;
case llvm::bitc::FIRST_APPLICATION_ABBREV:
llvm_unreachable("Unexpected abbrev id.");
}
}