[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, 29 insertions, 15 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 3f3408eb368..b09925b74c2 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -15,12 +15,14 @@
 #include "llvm/DebugInfo/CodeView/CodeView.h"
 #include "llvm/DebugInfo/CodeView/Line.h"
 #include "llvm/DebugInfo/CodeView/SymbolRecord.h"
+#include "llvm/DebugInfo/CodeView/TypeDumper.h"
 #include "llvm/DebugInfo/CodeView/TypeIndex.h"
 #include "llvm/DebugInfo/CodeView/TypeRecord.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCSectionCOFF.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/COFF.h"
+#include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Target/TargetSubtargetInfo.h"
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Target/TargetFrameLowering.h"
@@ -282,22 +284,34 @@ void CodeViewDebug::emitTypeInformation() {
   OS.SwitchSection(Asm->getObjFileLowering().getCOFFDebugTypesSection());
   emitCodeViewMagicVersion();
 
+  SmallString<8> CommentPrefix;
+  if (OS.isVerboseAsm()) {
+    CommentPrefix += '\t';
+    CommentPrefix += Asm->MAI->getCommentString();
+    CommentPrefix += ' ';
+  }
+
+  CVTypeDumper CVTD(nullptr, /*PrintRecordBytes=*/false);
   TypeTable.ForEachRecord(
-      [&](TypeIndex Index, const MemoryTypeTableBuilder::Record *R) {
-        // Each record should be 4 byte aligned. We achieve that by emitting
-        // LF_PAD padding bytes. The on-disk record size includes the padding
-        // bytes so that consumers don't have to skip past them.
-        uint64_t RecordSize = R->size() + 2;
-        uint64_t AlignedSize = alignTo(RecordSize, 4);
-        uint64_t AlignedRecordSize = AlignedSize - 2;
-        assert(AlignedRecordSize < (1 << 16) && "type record size overflow");
-        OS.AddComment("Type record length");
-        OS.EmitIntValue(AlignedRecordSize, 2);
-        OS.AddComment("Type record data");
-        OS.EmitBytes(StringRef(R->data(), R->size()));
-        // Pad the record with LF_PAD bytes.
-        for (unsigned I = AlignedSize - RecordSize; I > 0; --I)
-          OS.EmitIntValue(LF_PAD0 + I, 1);
+      [&](TypeIndex Index, StringRef Record) {
+        if (OS.isVerboseAsm()) {
+          // Emit a block comment describing the type record for readability.
+          SmallString<512> CommentBlock;
+          raw_svector_ostream CommentOS(CommentBlock);
+          ScopedPrinter SP(CommentOS);
+          SP.setPrefix(CommentPrefix);
+          CVTD.setPrinter(&SP);
+          bool DumpSuccess =
+              CVTD.dump({Record.bytes_begin(), Record.bytes_end()});
+          (void)DumpSuccess;
+          assert(DumpSuccess && "produced malformed type record");
+          // emitRawComment will insert its own tab and comment string before
+          // the first line, so strip off our first one. It also prints its own
+          // newline.
+          OS.emitRawComment(
+              CommentOS.str().drop_front(CommentPrefix.size() - 1).rtrim());
+        }
+        OS.EmitBinaryData(Record);
       });
 }