[DebugInfo] Enable debug information for C99 VLA types

Summary:
This patch enables debugging of C99 VLA types by generating more precise
LLVM Debug metadata, using the extended DISubrange 'count' field that
takes a DIVariable.
    
This should implement:
  Bug 30553: Debug info generated for arrays is not what GDB expects (not as good as GCC's)
https://bugs.llvm.org/show_bug.cgi?id=30553

Reviewers: echristo, aprantl, dexonsmith, clayborg, pcc, kristof.beyls, dblaikie

Reviewed By: aprantl

Subscribers: jholewinski, schweitz, davide, fhahn, JDevlieghere, cfe-commits

Differential Revision: https://reviews.llvm.org/D41698

llvm-svn: 323952

1 files changed, 4 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index fb919d7b028..052ebcaf389 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -237,9 +237,10 @@ llvm::Value *CodeGenFunction::getTypeSize(QualType Ty) {
   if (SizeInChars.isZero()) {
     // getTypeSizeInChars() returns 0 for a VLA.
     while (auto *VAT = C.getAsVariableArrayType(Ty)) {
-      llvm::Value *ArraySize;
-      std::tie(ArraySize, Ty) = getVLASize(VAT);
-      Size = Size ? Builder.CreateNUWMul(Size, ArraySize) : ArraySize;
+      auto VlaSize = getVLASize(VAT);
+      Ty = VlaSize.Type;
+      Size = Size ? Builder.CreateNUWMul(Size, VlaSize.NumElts)
+                  : VlaSize.NumElts;
     }
     SizeInChars = C.getTypeSizeInChars(Ty);
     if (SizeInChars.isZero())