Change Metadata Index emission in the bitcode to use 2x32 bits for the placeholder

The Bitstream reader and writer are limited to handle a "size_t" at
most, which means that we can't backpatch and read back a 64bits
value on 32 bits platform.

llvm-svn: 290693

3 files changed, 10 insertions, 4 deletions

diff --git a/llvm/include/llvm/Bitcode/BitstreamWriter.h b/llvm/include/llvm/Bitcode/BitstreamWriter.h
index 06113869ad6..d31989e9c89 100644
--- a/llvm/include/llvm/Bitcode/BitstreamWriter.h
+++ b/llvm/include/llvm/Bitcode/BitstreamWriter.h
@@ -284,7 +284,7 @@ private:
     default: llvm_unreachable("Unknown encoding!");
     case BitCodeAbbrevOp::Fixed:
       if (Op.getEncodingData())
-        Emit64(V, (unsigned)Op.getEncodingData());
+        Emit((unsigned)V, (unsigned)Op.getEncodingData());
       break;
     case BitCodeAbbrevOp::VBR:
       if (Op.getEncodingData())
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index b7f753e1d62..c10ba2399e7 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1920,7 +1920,8 @@ void ModuleBitcodeWriter::writeModuleMetadata() {
 
   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
-  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 64));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
+  Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
   unsigned OffsetAbbrev = Stream.EmitAbbrev(Abbv);
 
   Abbv = new BitCodeAbbrev();
@@ -1939,7 +1940,7 @@ void ModuleBitcodeWriter::writeModuleMetadata() {
     // which is written after the records, so that it can include
     // the offset of each entry. The placeholder offset will be
     // updated after all records are emitted.
-    uint64_t Vals[] = {0};
+    uint64_t Vals[] = {0, 0};
     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
   }
 
diff --git a/llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp b/llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
index 3220063275b..f97a18448f0 100644
--- a/llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
+++ b/llvm/tools/llvm-bcanalyzer/llvm-bcanalyzer.cpp
@@ -609,7 +609,12 @@ static bool ParseBlock(BitstreamCursor &Stream, BitstreamBlockInfo &BlockInfo,
       // and validate its forward reference offset was correct!
       if (BlockID == bitc::METADATA_BLOCK_ID) {
         if (Code == bitc::METADATA_INDEX_OFFSET) {
-          MetadataIndexOffset = Stream.GetCurrentBitNo() + Record[0];
+          if (Record.size() != 2)
+            outs() << "(Invalid record)";
+          else {
+            auto Offset = Record[0] + (Record[1] << 32);
+            MetadataIndexOffset = Stream.GetCurrentBitNo() + Offset;
+          }
         }
         if (Code == bitc::METADATA_INDEX) {
           outs() << " (offset ";