[Debug Info] remove DITrivialType and use null to represent unspecified param.

Per feedback on r214111, we are going to use null to represent unspecified
parameter. If the type array is {null}, it means a function that returns void;
If the type array is {null, null}, it means a variadic function that returns
void. In summary if we have more than one element in the type array and the last
element is null, it is a variadic function.

rdar://17628609

llvm-svn: 214189

4 files changed, 12 insertions, 31 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d58e47eaf03..d0958c0e975 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -469,11 +469,13 @@ DIE *DwarfDebug::createScopeChildrenDIE(
     // If this is a variadic function, add an unspecified parameter.
     DISubprogram SP(Scope->getScopeNode());
     DITypeArray FnArgs = SP.getType().getTypeArray();
-    if (resolve(FnArgs.getElement(FnArgs.getNumElements() - 1))
-            .isUnspecifiedParameter()) {
+    // If we have a single element of null, it is a function that returns void.
+    // If we have more than one elements and the last one is null, it is a
+    // variadic function.
+    if (FnArgs.getNumElements() > 1 &&
+        !resolve(FnArgs.getElement(FnArgs.getNumElements() - 1)))
       Children.push_back(
           make_unique<DIE>(dwarf::DW_TAG_unspecified_parameters));
-    }
   }
 
   // Collect lexical scope children first.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 43c6de5b0c3..f49eaca8c23 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1132,7 +1132,7 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, DIDerivedType DTy) {
 void DwarfUnit::constructSubprogramArguments(DIE &Buffer, DITypeArray Args) {
   for (unsigned i = 1, N = Args.getNumElements(); i < N; ++i) {
     DIType Ty = resolve(Args.getElement(i));
-    if (Ty.isUnspecifiedParameter()) {
+    if (!Ty) {
       assert(i == N-1 && "Unspecified parameter must be the last argument");
       createAndAddDIE(dwarf::DW_TAG_unspecified_parameters, Buffer);
     } else {
@@ -1168,7 +1168,7 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
 
     bool isPrototyped = true;
     if (Elements.getNumElements() == 2 &&
-        resolve(Elements.getElement(1)).isUnspecifiedParameter())
+        !resolve(Elements.getElement(1)))
       isPrototyped = false;
 
     constructSubprogramArguments(Buffer, Elements);
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index 16ff8a07570..2903b9d3453 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -875,11 +875,8 @@ void DIBuilder::retainType(DIType T) {
 
 /// createUnspecifiedParameter - Create unspeicified type descriptor
 /// for the subroutine type.
-DITrivialType DIBuilder::createUnspecifiedParameter() {
-  Value *Elts[] = {
-    GetTagConstant(VMContext, dwarf::DW_TAG_unspecified_parameters)
-  };
-  return DITrivialType(MDNode::get(VMContext, Elts));
+DIBasicType DIBuilder::createUnspecifiedParameter() {
+  return DIBasicType(nullptr);
 }
 
 /// createForwardDecl - Create a temporary forward-declared type that
diff --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index b97358545a5..b08755ed707 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -39,7 +39,6 @@ bool DIDescriptor::Verify() const {
   return DbgNode &&
          (DIDerivedType(DbgNode).Verify() ||
           DICompositeType(DbgNode).Verify() || DIBasicType(DbgNode).Verify() ||
-          DITrivialType(DbgNode).Verify() ||
           DIVariable(DbgNode).Verify() || DISubprogram(DbgNode).Verify() ||
           DIGlobalVariable(DbgNode).Verify() || DIFile(DbgNode).Verify() ||
           DICompileUnit(DbgNode).Verify() || DINameSpace(DbgNode).Verify() ||
@@ -155,10 +154,6 @@ MDNode *DIVariable::getInlinedAt() const { return getNodeField(DbgNode, 7); }
 // Predicates
 //===----------------------------------------------------------------------===//
 
-bool DIDescriptor::isTrivialType() const {
-  return DbgNode && getTag() == dwarf::DW_TAG_unspecified_parameters;
-}
-
 bool DIDescriptor::isSubroutineType() const {
   return isCompositeType() && getTag() == dwarf::DW_TAG_subroutine_type;
 }
@@ -233,8 +228,7 @@ bool DIDescriptor::isVariable() const {
 
 /// isType - Return true if the specified tag is legal for DIType.
 bool DIDescriptor::isType() const {
-  return isBasicType() || isCompositeType() || isDerivedType() ||
-         isTrivialType();
+  return isBasicType() || isCompositeType() || isDerivedType();
 }
 
 /// isSubprogram - Return true if the specified tag is legal for
@@ -250,12 +244,6 @@ bool DIDescriptor::isGlobalVariable() const {
                      getTag() == dwarf::DW_TAG_constant);
 }
 
-/// isUnspecifiedParmeter - Return true if the specified tag is
-/// DW_TAG_unspecified_parameters.
-bool DIDescriptor::isUnspecifiedParameter() const {
-  return DbgNode && getTag() == dwarf::DW_TAG_unspecified_parameters;
-}
-
 /// isScope - Return true if the specified tag is one of the scope
 /// related tag.
 bool DIDescriptor::isScope() const {
@@ -459,7 +447,7 @@ bool DIType::Verify() const {
 
   // FIXME: Sink this into the various subclass verifies.
   uint16_t Tag = getTag();
-  if (!isBasicType() && !isTrivialType() && Tag != dwarf::DW_TAG_const_type &&
+  if (!isBasicType() && Tag != dwarf::DW_TAG_const_type &&
       Tag != dwarf::DW_TAG_volatile_type && Tag != dwarf::DW_TAG_pointer_type &&
       Tag != dwarf::DW_TAG_ptr_to_member_type &&
       Tag != dwarf::DW_TAG_reference_type &&
@@ -474,8 +462,6 @@ bool DIType::Verify() const {
   // a CompositeType.
   if (isBasicType())
     return DIBasicType(DbgNode).Verify();
-  else if (isTrivialType())
-    return DITrivialType(DbgNode).Verify();
   else if (isCompositeType())
     return DICompositeType(DbgNode).Verify();
   else if (isDerivedType())
@@ -489,10 +475,6 @@ bool DIBasicType::Verify() const {
   return isBasicType() && DbgNode->getNumOperands() == 10;
 }
 
-bool DITrivialType::Verify() const {
-  return isTrivialType() && DbgNode->getNumOperands() == 1;
-}
-
 /// Verify - Verify that a derived type descriptor is well formed.
 bool DIDerivedType::Verify() const {
   // Make sure DerivedFrom @ field 9 is TypeRef.
@@ -1297,7 +1279,7 @@ void DIEnumerator::printInternal(raw_ostream &OS) const {
 }
 
 void DIType::printInternal(raw_ostream &OS) const {
-  if (!DbgNode || isTrivialType())
+  if (!DbgNode)
     return;
 
   StringRef Res = getName();