Debug info: Support variadic functions.

Variadic functions have an unspecified parameter tag after the last
argument. In IR this is represented as an unspecified parameter in the
subroutine type.

Paired commit with CFE.

rdar://problem/13690847

llvm-svn: 202184

3 files changed, 37 insertions, 21 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 2425948ae9a..f9ee2705a39 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -582,7 +582,7 @@ DIE *DwarfDebug::createScopeChildrenDIE(DwarfCompileUnit *TheCU,
   DIE *ObjectPointer = NULL;
 
   // Collect arguments for current function.
-  if (LScopes.isCurrentFunctionScope(Scope))
+  if (LScopes.isCurrentFunctionScope(Scope)) {
     for (unsigned i = 0, N = CurrentFnArguments.size(); i < N; ++i)
       if (DbgVariable *ArgDV = CurrentFnArguments[i])
         if (DIE *Arg =
@@ -592,6 +592,16 @@ DIE *DwarfDebug::createScopeChildrenDIE(DwarfCompileUnit *TheCU,
             ObjectPointer = Arg;
         }
 
+    // Create the unspecified parameter that marks a function as variadic.
+    DISubprogram SP(Scope->getScopeNode());
+    assert(SP.Verify());
+    DIArray FnArgs = SP.getType().getTypeArray();
+    if (FnArgs.getElement(FnArgs.getNumElements()-1).isUnspecifiedParameter()) {
+      DIE *Ellipsis = new DIE(dwarf::DW_TAG_unspecified_parameters);
+      Children.push_back(Ellipsis);
+    }
+  }
+
   // Collect lexical scope children first.
   const SmallVectorImpl<DbgVariable *> &Variables =
       ScopeVariables.lookup(Scope);
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 81dbfc505ac..4626c43f568 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -1139,6 +1139,22 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, DIDerivedType DTy) {
     addSourceLine(&Buffer, DTy);
 }
 
+/// constructSubprogramArguments - Construct function argument DIEs.
+void DwarfUnit::constructSubprogramArguments(DIE &Buffer, DIArray Args) {
+    for (unsigned i = 1, N = Args.getNumElements(); i < N; ++i) {
+      DIDescriptor Ty = Args.getElement(i);
+      if (Ty.isUnspecifiedParameter()) {
+        assert(i == N-1 && "ellipsis must be the last argument");
+        createAndAddDIE(dwarf::DW_TAG_unspecified_parameters, Buffer);
+      } else {
+        DIE *Arg = createAndAddDIE(dwarf::DW_TAG_formal_parameter, Buffer);
+        addType(Arg, DIType(Ty));
+        if (DIType(Ty).isArtificial())
+          addFlag(Arg, dwarf::DW_AT_artificial);
+      }
+    }
+}
+
 /// constructTypeDIE - Construct type DIE from DICompositeType.
 void DwarfUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
   // Add name if not anonymous or intermediate type.
@@ -1162,19 +1178,12 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, DICompositeType CTy) {
       addType(&Buffer, RTy);
 
     bool isPrototyped = true;
-    // Add arguments.
-    for (unsigned i = 1, N = Elements.getNumElements(); i < N; ++i) {
-      DIDescriptor Ty = Elements.getElement(i);
-      if (Ty.isUnspecifiedParameter()) {
-        createAndAddDIE(dwarf::DW_TAG_unspecified_parameters, Buffer);
-        isPrototyped = false;
-      } else {
-        DIE *Arg = createAndAddDIE(dwarf::DW_TAG_formal_parameter, Buffer);
-        addType(Arg, DIType(Ty));
-        if (DIType(Ty).isArtificial())
-          addFlag(Arg, dwarf::DW_AT_artificial);
-      }
-    }
+    if (Elements.getNumElements() == 2 &&
+        Elements.getElement(1).isUnspecifiedParameter())
+      isPrototyped = false;
+
+    constructSubprogramArguments(Buffer, Elements);
+
     // Add prototype flag if we're dealing with a C language and the
     // function has been prototyped.
     uint16_t Language = getLanguage();
@@ -1457,13 +1466,7 @@ DIE *DwarfUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
 
     // Add arguments. Do not add arguments for subprogram definition. They will
     // be handled while processing variables.
-    for (unsigned i = 1, N = Args.getNumElements(); i < N; ++i) {
-      DIE *Arg = createAndAddDIE(dwarf::DW_TAG_formal_parameter, *SPDie);
-      DIType ATy(Args.getElement(i));
-      addType(Arg, ATy);
-      if (ATy.isArtificial())
-        addFlag(Arg, dwarf::DW_AT_artificial);
-    }
+    constructSubprogramArguments(*SPDie, Args);
   }
 
   if (SP.isArtificial())
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
index 370ecbf831e..bf77272b8a2 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -476,6 +476,9 @@ protected:
   DIE *getOrCreateStaticMemberDIE(DIDerivedType DT);
 
 private:
+  /// constructSubprogramArguments - Construct function argument DIEs.
+  void constructSubprogramArguments(DIE &Buffer, DIArray Args);
+
   /// constructTypeDIE - Construct basic type die from DIBasicType.
   void constructTypeDIE(DIE &Buffer, DIBasicType BTy);