[codeview] Improve readability of type record assembly

Adds the method MCStreamer::EmitBinaryData, which is usually an alias
for EmitBytes. In the MCAsmStreamer case, it is overridden to emit hex
dump output like this:
        .byte   0x0e, 0x00, 0x08, 0x10
        .byte   0x03, 0x00, 0x00, 0x00
        .byte   0x00, 0x00, 0x00, 0x00
        .byte   0x00, 0x10, 0x00, 0x00

Also, when verbose asm comments are enabled, this patch prints the dump
output for each comment before its record, like this:
        # ArgList (0x1000) {
        #   TypeLeafKind: LF_ARGLIST (0x1201)
        #   NumArgs: 0
        #   Arguments [
        #   ]
        # }
        .byte   0x06, 0x00, 0x01, 0x12
        .byte   0x00, 0x00, 0x00, 0x00

This should make debugging easier and testing more convenient.

Reviewers: aaboud

Subscribers: majnemer, zturner, amccarth, aaboud, llvm-commits

Differential Revision: http://reviews.llvm.org/D20711

llvm-svn: 271313

1 files changed, 19 insertions, 8 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/MemoryTypeTableBuilder.cpp b/llvm/lib/DebugInfo/CodeView/MemoryTypeTableBuilder.cpp
index 9afce92eeb1..8b9e73b94ff 100644
--- a/llvm/lib/DebugInfo/CodeView/MemoryTypeTableBuilder.cpp
+++ b/llvm/lib/DebugInfo/CodeView/MemoryTypeTableBuilder.cpp
@@ -13,23 +13,34 @@
 using namespace llvm;
 using namespace codeview;
 
-MemoryTypeTableBuilder::Record::Record(StringRef RData)
-    : Size(RData.size()), Data(new char[RData.size()]) {
-  memcpy(Data.get(), RData.data(), RData.size());
-}
-
 TypeIndex MemoryTypeTableBuilder::writeRecord(StringRef Data) {
+  assert(Data.size() <= UINT16_MAX);
   auto I = HashedRecords.find(Data);
   if (I != HashedRecords.end()) {
     return I->second;
   }
 
-  std::unique_ptr<Record> R(new Record(Data));
+  // The record provided by the user lacks the 2 byte size field prefix and is
+  // not padded to 4 bytes. Ultimately, that is what gets emitted in the object
+  // file, so pad it out now.
+  const int SizeOfRecLen = 2;
+  const int Align = 4;
+  int TotalSize = alignTo(Data.size() + SizeOfRecLen, Align);
+  assert(TotalSize - SizeOfRecLen <= UINT16_MAX);
+  char *Mem =
+      reinterpret_cast<char *>(RecordStorage.Allocate(TotalSize, Align));
+  *reinterpret_cast<ulittle16_t *>(Mem) = uint16_t(TotalSize - SizeOfRecLen);
+  memcpy(Mem + SizeOfRecLen, Data.data(), Data.size());
+  for (int I = Data.size() + SizeOfRecLen; I < TotalSize; ++I)
+    Mem[I] = LF_PAD0 + (TotalSize - I);
 
   TypeIndex TI(static_cast<uint32_t>(Records.size()) +
                TypeIndex::FirstNonSimpleIndex);
-  HashedRecords.insert(std::make_pair(StringRef(R->data(), R->size()), TI));
-  Records.push_back(std::move(R));
+
+  // Use only the data supplied by the user as a key to the hash table, so that
+  // future lookups will succeed.
+  HashedRecords.insert(std::make_pair(StringRef(Mem + SizeOfRecLen, Data.size()), TI));
+  Records.push_back(StringRef(Mem, TotalSize));
 
   return TI;
 }