Debug info: Infrastructure to support debug locations for fragmented
variables (for example, by-value struct arguments passed in registers, or
large integer values split across several smaller registers).
On the IR level, this adds a new type of complex address operation OpPiece
to DIVariable that describes size and offset of a variable fragment.
On the DWARF emitter level, all pieces describing the same variable are
collected, sorted and emitted as DWARF expressions using the DW_OP_piece
and DW_OP_bit_piece operators.
http://reviews.llvm.org/D3373
rdar://problem/15928306
What this patch doesn't do / Future work:
- This patch only adds the backend machinery to make this work, patches
that change SROA and SelectionDAG's type legalizer to actually create
such debug info will follow. (http://reviews.llvm.org/D2680)
- Making the DIVariable complex expressions into an argument of dbg.value
will reduce the memory footprint of the debug metadata.
- The sorting/uniquing of pieces should be moved into DebugLocEntry,
to facilitate the merging of multi-piece entries.
llvm-svn: 214576
diff --git a/llvm/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h b/llvm/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h
index b9177f0..6f72b91 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DbgValueHistoryCalculator.h
@@ -28,9 +28,11 @@
// range. If end is not specified, location is valid until the start
// instruction of the next instruction range, or until the end of the
// function.
+public:
typedef std::pair<const MachineInstr *, const MachineInstr *> InstrRange;
typedef SmallVector<InstrRange, 4> InstrRanges;
typedef MapVector<const MDNode *, InstrRanges> InstrRangesMap;
+private:
InstrRangesMap VarInstrRanges;
public: