[DebugInfo] Align comments in debug_loc section
Summary:
This commit updates the BufferByteStreamer, used by DebugLocStream
to buffer bytes/comments to put in the debug_loc section, to
make sure that the Buffer and Comments vectors are synced.
Previously, when an SLEB128 or ULEB128 was emitted together with
a comment, the vectors could be out-of-sync if the LEB encoding
added several entries to the Buffer vectors, while we only added
a single entry to the Comments vector.
The goal with this is to get the comments in the debug_loc
section in the .s file correctly aligned.
Example (using ARM as target):
Instead of
.byte 144 @ sub-register DW_OP_regx
.byte 128 @ 256
.byte 2 @ DW_OP_piece
.byte 147 @ 8
.byte 8 @ sub-register DW_OP_regx
.byte 144 @ 257
.byte 129 @ DW_OP_piece
.byte 2 @ 8
.byte 147 @
.byte 8 @
we now get
.byte 144 @ sub-register DW_OP_regx
.byte 128 @ 256
.byte 2 @
.byte 147 @ DW_OP_piece
.byte 8 @ 8
.byte 144 @ sub-register DW_OP_regx
.byte 129 @ 257
.byte 2 @
.byte 147 @ DW_OP_piece
.byte 8 @ 8
Reviewers: JDevlieghere, rnk, aprantl
Reviewed By: aprantl
Subscribers: davide, Ka-Ka, uabelho, aemerson, javed.absar, kristof.beyls, llvm-commits, JDevlieghere
Differential Revision: https://reviews.llvm.org/D41763
llvm-svn: 321907
diff --git a/llvm/lib/CodeGen/AsmPrinter/ByteStreamer.h b/llvm/lib/CodeGen/AsmPrinter/ByteStreamer.h
index aaf6180..34ad66f 100644
--- a/llvm/lib/CodeGen/AsmPrinter/ByteStreamer.h
+++ b/llvm/lib/CodeGen/AsmPrinter/ByteStreamer.h
@@ -93,15 +93,27 @@
}
void EmitSLEB128(uint64_t DWord, const Twine &Comment) override {
raw_svector_ostream OSE(Buffer);
- encodeSLEB128(DWord, OSE);
- if (GenerateComments)
+ unsigned Length = encodeSLEB128(DWord, OSE);
+ if (GenerateComments) {
Comments.push_back(Comment.str());
+ // Add some empty comments to keep the Buffer and Comments vectors aligned
+ // with each other.
+ for (size_t i = 1; i < Length; ++i)
+ Comments.push_back("");
+
+ }
}
void EmitULEB128(uint64_t DWord, const Twine &Comment) override {
raw_svector_ostream OSE(Buffer);
- encodeULEB128(DWord, OSE);
- if (GenerateComments)
+ unsigned Length = encodeULEB128(DWord, OSE);
+ if (GenerateComments) {
Comments.push_back(Comment.str());
+ // Add some empty comments to keep the Buffer and Comments vectors aligned
+ // with each other.
+ for (size_t i = 1; i < Length; ++i)
+ Comments.push_back("");
+
+ }
}
};