Add template type and value parameter metadata nodes to template variable specializations

[ormris]

Summary

Add an optional attribute referring to a tuple of type and value template parameter nodes to the DIGlobalVariable node. This allows us to record the parameters of template variable specializations.

[JDevlieghere]

lib/CodeGen/CGDebugInfo.cpp

3125

What's the meaning of this comment?

lib/CodeGen/CGDebugInfo.h

654

s/templateParameters/TemplateParameters/ (same for the rest of this patch)

[ormris]

lib/CodeGen/CGDebugInfo.cpp

3125

Hmm... That should be removed.

lib/CodeGen/CGDebugInfo.h

654

OK. Will fix.

[ormris]

• Removed unneeded comment
• Renamed variable
• Rebased

[JDevlieghere]

Generally this looks good, but I'd like for the other to have a look first (at this and the other patch) before accepting.

lib/CodeGen/CGDebugInfo.cpp

1783

Might be nice to add a comment here saying what you're doing in this block and below. Looks like the top one is for partial specialization and the bottom one for the general case?

1783

I also suggest to extract TS->getSpecializedTemplateOrPartial() into a variable to make this a little less dense.

[ormris]

In D52058#1237868, @JDevlieghere wrote:

Generally this looks good, but I'd like for the other to have a look first (at this and the other patch) before accepting.

Sounds good. Thanks for your comments!

lib/CodeGen/CGDebugInfo.cpp

1783

Hmm... Yeah. I'll take a look at clarifying this section.

[ormris]

Ping

[ormris]

• Clarify CGDebugInfo::CollectVarTemplateParams

[ormris]

Ping Ping

[JDevlieghere]

LGTM

[ormris]

Thanks! I'll go ahead and commit this.

lib/CodeGen/CGDebugInfo.h

#include "clang/Basic/OpenCLImageTypes.def"
   llvm::DINodeArray CollectTemplateParams(const TemplateParameterList *TPList,
                                           ArrayRef<TemplateArgument> TAList,
                                           llvm::DIFile *Unit);
   /// A helper function to collect debug info for function template
   /// parameters.
   llvm::DINodeArray CollectFunctionTemplateParams(const FunctionDecl *FD,
                                                   llvm::DIFile *Unit);
 
+  /// A helper function to collect debug info for function template
+  /// parameters.
+  llvm::DINodeArray CollectVarTemplateParams(const VarDecl *VD,
+                                             llvm::DIFile *Unit);
+
   /// A helper function to collect debug info for template
   /// parameters.
   llvm::DINodeArray
   CollectCXXTemplateParams(const ClassTemplateSpecializationDecl *TS,
                            llvm::DIFile *F);
 
   llvm::DIType *createFieldType(StringRef name, QualType type,
                                 SourceLocation loc, AccessSpecifier AS,
void collectFunctionDeclProps(GlobalDecl GD, llvm::DIFile *Unit,
                                 StringRef &Name, StringRef &LinkageName,
                                 llvm::DIScope *&FDContext,
                                 llvm::DINodeArray &TParamsArray,
                                 llvm::DINode::DIFlags &Flags);
 
   /// Collect various properties of a VarDecl.
   void collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
                            unsigned &LineNo, QualType &T, StringRef &Name,
-                           StringRef &LinkageName, llvm::DIScope *&VDContext);
+                           StringRef &LinkageName,
+                           llvm::MDTuple *&TemplateParameters,
+                           llvm::DIScope *&VDContext);
 
   /// Allocate a copy of \p A using the DebugInfoNames allocator
   /// and return a reference to it. If multiple arguments are given the strings
   /// are concatenated.
   StringRef internString(StringRef A, StringRef B = StringRef()) {
     char *Data = DebugInfoNames.Allocate<char>(A.size() + B.size());
     if (!A.empty())
       std::memcpy(Data, A.data(), A.size());

lib/CodeGen/CGDebugInfo.cpp

 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/MD5.h"
 #include "llvm/Support/Path.h"
 using namespace clang;
 using namespace clang::CodeGen;
 
 static uint32_t getTypeAlignIfRequired(const Type *Ty, const ASTContext &Ctx) {
const TemplateParameterList *TList = FD->getTemplateSpecializationInfo()
                                              ->getTemplate()
                                              ->getTemplateParameters();
     return CollectTemplateParams(
         TList, FD->getTemplateSpecializationArgs()->asArray(), Unit);
   }
   return llvm::DINodeArray();
 }
 
+llvm::DINodeArray CGDebugInfo::CollectVarTemplateParams(const VarDecl *VL,
+    llvm::DIFile *Unit) {
+  if (auto *TS = dyn_cast<VarTemplateSpecializationDecl>(VL)) {
+    auto T = TS->getSpecializedTemplateOrPartial();
+    auto TA = TS->getTemplateArgs().asArray();
+    // Collect parameters for a partial specialization
+    if (T.is<VarTemplatePartialSpecializationDecl *>()) {
+      const TemplateParameterList *TList =
+        T.get<VarTemplatePartialSpecializationDecl *>()
+        ->getTemplateParameters();
+      return CollectTemplateParams(TList, TA, Unit);
+    }
+
+    // Collect parameters for an explicit specialization
+    if (T.is<VarTemplateDecl *>()) {
+      const TemplateParameterList *TList = T.get<VarTemplateDecl *>()
+        ->getTemplateParameters();
+      return CollectTemplateParams(TList, TA, Unit);
+    }
+  }
+  return llvm::DINodeArray();
+}
+
 llvm::DINodeArray CGDebugInfo::CollectCXXTemplateParams(
     const ClassTemplateSpecializationDecl *TSpecial, llvm::DIFile *Unit) {
   // Always get the full list of parameters, not just the ones from
   // the specialization.
   TemplateParameterList *TPList =
       TSpecial->getSpecializedTemplate()->getTemplateParameters();
   const TemplateArgumentList &TAList = TSpecial->getTemplateArgs();
   return CollectTemplateParams(TPList, TAList.asArray(), Unit);
if (DebugKind >= codegenoptions::LimitedDebugInfo) {
     // Collect template parameters.
     TParamsArray = CollectFunctionTemplateParams(FD, Unit);
   }
 }
 
 void CGDebugInfo::collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
                                       unsigned &LineNo, QualType &T,
                                       StringRef &Name, StringRef &LinkageName,
+                                      llvm::MDTuple *&TemplateParameters,
                                       llvm::DIScope *&VDContext) {
   Unit = getOrCreateFile(VD->getLocation());
   LineNo = getLineNumber(VD->getLocation());
 
   setLocation(VD->getLocation());
 
   T = VD->getType();
   if (T->isIncompleteArrayType()) {
     // CodeGen turns int[] into int[1] so we'll do the same here.
     llvm::APInt ConstVal(32, 1);
     QualType ET = CGM.getContext().getAsArrayType(T)->getElementType();
 
     T = CGM.getContext().getConstantArrayType(ET, ConstVal, ArrayType::Normal,
                                               0);
   }
 
   Name = VD->getName();
   if (VD->getDeclContext() && !isa<FunctionDecl>(VD->getDeclContext()) &&
       !isa<ObjCMethodDecl>(VD->getDeclContext()))
     LinkageName = CGM.getMangledName(VD);
   if (LinkageName == Name)
     LinkageName = StringRef();
 
+  if (isa<VarTemplateSpecializationDecl>(VD)) {
+    llvm::DINodeArray parameterNodes = CollectVarTemplateParams(VD, &*Unit);
+    TemplateParameters = parameterNodes.get();
+  } else {
+    TemplateParameters = nullptr;
+  }
+
   // Since we emit declarations (DW_AT_members) for static members, place the
   // definition of those static members in the namespace they were declared in
   // in the source code (the lexical decl context).
   // FIXME: Generalize this for even non-member global variables where the
   // declaration and definition may have different lexical decl contexts, once
   // we have support for emitting declarations of (non-member) global variables.
   const DeclContext *DC = VD->isStaticDataMember() ? VD->getLexicalDeclContext()
                                                    : VD->getDeclContext();

 llvm::DIGlobalVariable *
 CGDebugInfo::getGlobalVariableForwardDeclaration(const VarDecl *VD) {
   QualType T;
   StringRef Name, LinkageName;
   SourceLocation Loc = VD->getLocation();
   llvm::DIFile *Unit = getOrCreateFile(Loc);
   llvm::DIScope *DContext = Unit;
   unsigned Line = getLineNumber(Loc);
+  llvm::MDTuple *TemplateParameters = nullptr;
 
-  collectVarDeclProps(VD, Unit, Line, T, Name, LinkageName, DContext);
+  collectVarDeclProps(VD, Unit, Line, T, Name, LinkageName, TemplateParameters,
+                      DContext);
   auto Align = getDeclAlignIfRequired(VD, CGM.getContext());
   auto *GV = DBuilder.createTempGlobalVariableFwdDecl(
       DContext, Name, LinkageName, Unit, Line, getOrCreateType(T, Unit),
-      !VD->isExternallyVisible(), nullptr, Align);
+      !VD->isExternallyVisible(), nullptr, TemplateParameters, Align);
   FwdDeclReplaceMap.emplace_back(
       std::piecewise_construct,
       std::make_tuple(cast<VarDecl>(VD->getCanonicalDecl())),
       std::make_tuple(static_cast<llvm::Metadata *>(GV)));
   return GV;
 }
 
 llvm::DINode *CGDebugInfo::getDeclarationOrDefinition(const Decl *D) {
return Var->addDebugInfo(
         cast<llvm::DIGlobalVariableExpression>(Cached->second));
 
   // Create global variable debug descriptor.
   llvm::DIFile *Unit = nullptr;
   llvm::DIScope *DContext = nullptr;
   unsigned LineNo;
   StringRef DeclName, LinkageName;
   QualType T;
-  collectVarDeclProps(D, Unit, LineNo, T, DeclName, LinkageName, DContext);
+  llvm::MDTuple *TemplateParameters = nullptr;
+  collectVarDeclProps(D, Unit, LineNo, T, DeclName, LinkageName,
+                      TemplateParameters, DContext);
 
   // Attempt to store one global variable for the declaration - even if we
   // emit a lot of fields.
   llvm::DIGlobalVariableExpression *GVE = nullptr;
 
   // If this is an anonymous union then we'll want to emit a global
   // variable for each member of the anonymous union so that it's possible
   // to find the name of any field in the union.
if (T->isUnionType() && DeclName.empty()) {
     unsigned AddressSpace =
         CGM.getContext().getTargetAddressSpace(D->getType());
     AppendAddressSpaceXDeref(AddressSpace, Expr);
 
     GVE = DBuilder.createGlobalVariableExpression(
         DContext, DeclName, LinkageName, Unit, LineNo, getOrCreateType(T, Unit),
         Var->hasLocalLinkage(),
         Expr.empty() ? nullptr : DBuilder.createExpression(Expr),
-        getOrCreateStaticDataMemberDeclarationOrNull(D), Align);
+        getOrCreateStaticDataMemberDeclarationOrNull(D), TemplateParameters,
+        Align);
     Var->addDebugInfo(GVE);
   }
   DeclCache[D->getCanonicalDecl()].reset(GVE);
 }
 
 void CGDebugInfo::EmitGlobalVariable(const ValueDecl *VD, const APValue &Init) {
   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   if (VD->hasAttr<NoDebugAttr>())
if (CGM.getContext().getTypeSize(VD->getType()) <= 64) {
     // FIXME: Add a representation for integer constants wider than 64 bits.
     if (Init.isInt())
       InitExpr =
           DBuilder.createConstantValueExpression(Init.getInt().getExtValue());
     else if (Init.isFloat())
       InitExpr = DBuilder.createConstantValueExpression(
           Init.getFloat().bitcastToAPInt().getZExtValue());
   }
+
+  llvm::MDTuple *TemplateParameters = nullptr;
+
+  if (isa<VarTemplateSpecializationDecl>(VD))
+    if (VarD) {
+      llvm::DINodeArray parameterNodes = CollectVarTemplateParams(VarD, &*Unit);
+      TemplateParameters = parameterNodes.get();
+    }
+
   GV.reset(DBuilder.createGlobalVariableExpression(
       DContext, Name, StringRef(), Unit, getLineNumber(VD->getLocation()), Ty,
       true, InitExpr, getOrCreateStaticDataMemberDeclarationOrNull(VarD),
-      Align));
+      TemplateParameters, Align));
 }
 
 llvm::DIScope *CGDebugInfo::getCurrentContextDescriptor(const Decl *D) {
   if (!LexicalBlockStack.empty())
     return LexicalBlockStack.back();
   llvm::DIScope *Mod = getParentModuleOrNull(D);
   return getContextDescriptor(D, Mod ? Mod : TheCU);
 }

test/CodeGenCXX/debug-info-template-member.cpp

 inline int add3(int x) {
   return MyClass().add<3>(x); // even though add<3> is ODR used, don't emit it since we don't codegen it
 }
 
 // The compile unit pulls in the global variables first.
 // CHECK: [[X]] = !DIGlobalVariableExpression(var: [[XV:.*]], expr: !DIExpression())
 // CHECK: [[XV]] = distinct !DIGlobalVariable(name: "x",
 // CHECK-SAME:                                type: ![[OUTER_FOO_INNER_ID:[0-9]+]]
+//
+// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
+// CHECK-SAME: name: "var"
+// CHECK-SAME: templateParams: {{![0-9]+}}
+// CHECK: !DITemplateTypeParameter(name: "T", type: [[TY:![0-9]+]])
+// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
+// CHECK-SAME: name: "var"
+// CHECK-SAME: templateParams: {{![0-9]+}}
+// CHECK: !DITemplateTypeParameter(name: "P", type: {{![0-9]+}})
+// CHECK: {{![0-9]+}} = distinct !DIGlobalVariable(
+// CHECK-SAME: name: "varray"
+// CHECK-SAME: templateParams: {{![0-9]+}}
+// CHECK: !DITemplateValueParameter(name: "N", type: [[TY]], value: i32 1)
 
 // CHECK: ![[OUTER_FOO_INNER_ID:[0-9]*]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "inner"{{.*}}, identifier:
 // CHECK: !DICompositeType(tag: DW_TAG_structure_type, name: "foo"
 // CHECK-SAME:             elements: [[FOO_MEM:![0-9]*]]
 // CHECK-SAME:             identifier: "_ZTS3foo"
 // CHECK: [[FOO_MEM]] = !{[[FOO_FUNC:![0-9]*]]}
 // CHECK: [[FOO_FUNC]] = !DISubprogram(name: "func", linkageName: "_ZN3foo4funcEN5outerIS_E5innerE",
 // CHECK-SAME:                         type: [[FOO_FUNC_TYPE:![0-9]*]]

 
 // Check that the member function template specialization and implicit special
 // members (the default ctor) refer to their class by scope, even though they
 // didn't appear in the class's member list (C_MEM). This prevents the functions
 // from being added to type units, while still appearing in the type
 // declaration/reference in the compile unit.
 // CHECK: !DISubprogram(name: "MyClass"
 // CHECK-SAME:          scope: [[C]]
+
+template <typename T>
+T var = T();
+template <typename P>
+P var<P *> = P();
+template <typename T, int N>
+T varray[N];
+void f3() {
+  var<int> = 1;
+  var<int *> = 1;
+  varray<int, 1>[0] = 1;
+}