[DebugInfo] Emit DWARF reference for DIVariable 'count' in DISubrange
Summary:
This patch implements the codegen of DWARF debug info for non-constant
'count' fields for DISubrange.
This is patch [2/3] in a series to extend LLVM's DISubrange Metadata
node to support debugging of C99 variable length arrays and vectors with
runtime length like the Scalable Vector Extension for AArch64. It is
also a first step towards representing more complex cases like arrays
in Fortran.
Reviewers: echristo, pcc, aprantl, dexonsmith, clayborg, kristof.beyls, dblaikie
Reviewed By: aprantl
Subscribers: fhahn, aemerson, rengolin, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D41696
llvm-svn: 323323
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 907ede0..71f452b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1335,7 +1335,13 @@
if (DefaultLowerBound == -1 || LowerBound != DefaultLowerBound)
addUInt(DW_Subrange, dwarf::DW_AT_lower_bound, None, LowerBound);
- if (Count != -1)
+ if (auto *CV = SR->getCount().dyn_cast<DIVariable*>()) {
+ // 'finishVariableDefinition' that creates the types for a variable is
+ // always called _after_ the DIEs for variables are created.
+ auto *CountVarDIE = getDIE(CV);
+ assert(CountVarDIE && "DIE for count is not yet instantiated");
+ addDIEEntry(DW_Subrange, dwarf::DW_AT_count, *CountVarDIE);
+ } else if (Count != -1)
// FIXME: An unbounded array should reference the expression that defines
// the array.
addUInt(DW_Subrange, dwarf::DW_AT_count, None, Count);