[DebugInfo] Append extended dereferencing mechanism to variables' DIExpression for targets that support more than one address space

Differential Revision: https://reviews.llvm.org/D29673

llvm-svn: 297397

2 files changed, 35 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 003b6c1872e..d8638c6f8d7 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -3272,6 +3272,20 @@ void CGDebugInfo::CreateLexicalBlock(SourceLocation Loc) {
       getColumnNumber(CurLoc)));
 }
 
+void CGDebugInfo::AppendAddressSpaceXDeref(
+    unsigned AddressSpace,
+    SmallVectorImpl<int64_t> &Expr) const {
+  Optional<unsigned> DWARFAddressSpace =
+      CGM.getTarget().getDWARFAddressSpace(AddressSpace);
+  if (!DWARFAddressSpace)
+    return;
+
+  Expr.push_back(llvm::dwarf::DW_OP_constu);
+  Expr.push_back(DWARFAddressSpace.getValue());
+  Expr.push_back(llvm::dwarf::DW_OP_swap);
+  Expr.push_back(llvm::dwarf::DW_OP_xderef);
+}
+
 void CGDebugInfo::EmitLexicalBlockStart(CGBuilderTy &Builder,
                                         SourceLocation Loc) {
   // Set our current location.
@@ -3422,13 +3436,16 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
     Line = getLineNumber(VD->getLocation());
     Column = getColumnNumber(VD->getLocation());
   }
-  SmallVector<int64_t, 9> Expr;
+  SmallVector<int64_t, 13> Expr;
   llvm::DINode::DIFlags Flags = llvm::DINode::FlagZero;
   if (VD->isImplicit())
     Flags |= llvm::DINode::FlagArtificial;
 
   auto Align = getDeclAlignIfRequired(VD, CGM.getContext());
 
+  unsigned AddressSpace = CGM.getContext().getTargetAddressSpace(VD->getType());
+  AppendAddressSpaceXDeref(AddressSpace, Expr);
+
   // If this is the first argument and it is implicit then
   // give it an object pointer flag.
   // FIXME: There has to be a better way to do this, but for static
@@ -3857,9 +3874,16 @@ void CGDebugInfo::EmitGlobalVariable(llvm::GlobalVariable *Var,
     GVE = CollectAnonRecordDecls(RD, Unit, LineNo, LinkageName, Var, DContext);
   } else {
     auto Align = getDeclAlignIfRequired(D, CGM.getContext());
+
+    SmallVector<int64_t, 4> Expr;
+    unsigned AddressSpace =
+        CGM.getContext().getTargetAddressSpace(D->getType());
+    AppendAddressSpaceXDeref(AddressSpace, Expr);
+
     GVE = DBuilder.createGlobalVariableExpression(
         DContext, DeclName, LinkageName, Unit, LineNo, getOrCreateType(T, Unit),
-        Var->hasLocalLinkage(), /*Expr=*/nullptr,
+        Var->hasLocalLinkage(),
+        Expr.empty() ? nullptr : DBuilder.createExpression(Expr),
         getOrCreateStaticDataMemberDeclarationOrNull(D), Align);
     Var->addDebugInfo(GVE);
   }
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index c9a44cf70df..c6d1c66e131 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -293,6 +293,15 @@ class CGDebugInfo {
   /// Create a new lexical block node and push it on the stack.
   void CreateLexicalBlock(SourceLocation Loc);
 
+  /// If target-specific LLVM \p AddressSpace directly maps to target-specific
+  /// DWARF address space, appends extended dereferencing mechanism to complex
+  /// expression \p Expr. Otherwise, does nothing.
+  ///
+  /// Extended dereferencing mechanism is has the following format:
+  ///     DW_OP_constu <DWARF Address Space> DW_OP_swap DW_OP_xderef
+  void AppendAddressSpaceXDeref(unsigned AddressSpace,
+                                SmallVectorImpl<int64_t> &Expr) const;
+
 public:
   CGDebugInfo(CodeGenModule &CGM);
   ~CGDebugInfo();