[Bitcode] Address backwards compat bug in r342631

r342631 expanded bitc::METADATA_LOCATION by one element. The bitcode
metadata loader was changed in a backwards-incompatible way, leading to
crashes when disassembling old bitcode:

  assertion: empty() && "PlaceholderQueue hasn't been flushed before being destroyed"
  Assertion failed: (empty() && "PlaceholderQueue hasn't been flushed before being destroyed")

This commit teaches the metadata loader to assume that the newly-added
IsImplicitCode bit is 'false' when not present in old bitcode. I've added a
bitcode compat regression test.

rdar://44645820

llvm-svn: 342678
This commit is contained in:
Vedant Kumar 2018-09-20 18:59:33 +00:00
parent 8852ffb12f
commit 3117751229
3 changed files with 10 additions and 2 deletions

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@ -1139,7 +1139,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
break;
}
case bitc::METADATA_LOCATION: {
if (Record.size() != 6)
if (Record.size() != 5 && Record.size() != 6)
return error("Invalid record");
IsDistinct = Record[0];
@ -1147,7 +1147,7 @@ Error MetadataLoader::MetadataLoaderImpl::parseOneMetadata(
unsigned Column = Record[2];
Metadata *Scope = getMD(Record[3]);
Metadata *InlinedAt = getMDOrNull(Record[4]);
bool ImplicitCode = Record[5];
bool ImplicitCode = Record.size() == 6 && Record[5];
MetadataList.assignValue(
GET_OR_DISTINCT(DILocation, (Context, Line, Column, Scope, InlinedAt,
ImplicitCode)),

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@ -0,0 +1,8 @@
; AppleClang-700 uses a debug info version that isn't recognized by llvm.org
; compilers. However, it does produce valid bitcode which should parse without
; crashing the metadata loader.
RUN: llvm-dis < %S/Inputs/apple-clang-700-O3-g-1.bc 2>&1 \
RUN: | FileCheck %s -check-prefix INVALID-VERSION
INVALID-VERSION: warning: ignoring debug info with an invalid version (700000003)