From f61a563a19a3f4c999011c8c6287717532dcdfd9 Mon Sep 17 00:00:00 2001 From: Teresa Johnson Date: Wed, 14 Nov 2018 20:58:04 +0000 Subject: [ThinLTO] Fix a crash in lazy loading of Metadata This is a revised version of D41474. When the debug location is parsed in BitcodeReader::parseFunction, the scope and inlinedAt MDNodes are obtained via MDLoader->getMDNodeFwdRefOrNull(), which will create a forward ref if they were not yet loaded. Specifically, if one of these MDNodes is in the module level metadata block, and this is during ThinLTO importing, that metadata block is lazily loaded. Most places in that invoke getMDNodeFwdRefOrNull have a corresponding call to resolveForwardRefsAndPlaceholders which will take care of resolving them. E.g. places that call getMetadataFwdRefOrLoad, or at the end of parsing a function-level metadata block, or at the end of the initial lazy load of module level metadata in order to handle invocations of getMDNodeFwdRefOrNull for named metadata and global object attachments. However, the calls for the scope/inlinedAt of debug locations are not backed by any such call to resolveForwardRefsAndPlaceholders. To fix this, change the scope and inlinedAt parsing to instead use getMetadataFwdRefOrLoad, which will ensure the forward refs to lazily loaded metadata are resolved. Fixes PR35472. llvm-svn: 346891 --- llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'llvm/lib/Bitcode/Reader/BitcodeReader.cpp') diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp index 3b1d54f82cb..5f5167c9a2e 100644 --- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp +++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp @@ -3548,12 +3548,14 @@ Error BitcodeReader::parseFunctionBody(Function *F) { MDNode *Scope = nullptr, *IA = nullptr; if (ScopeID) { - Scope = MDLoader->getMDNodeFwdRefOrNull(ScopeID - 1); + Scope = dyn_cast_or_null( + MDLoader->getMetadataFwdRefOrLoad(ScopeID - 1)); if (!Scope) return error("Invalid record"); } if (IAID) { - IA = MDLoader->getMDNodeFwdRefOrNull(IAID - 1); + IA = dyn_cast_or_null( + MDLoader->getMetadataFwdRefOrLoad(IAID - 1)); if (!IA) return error("Invalid record"); } -- cgit v1.2.3