MFC debug info for variadic functions

r264826: Merge LLVM r202188:

    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 r202185.

    rdar://problem/13690847

    This re-applies r202184 + a bugfix in DwarfDebug's argument handling.

  This merge includes a change to use the LLVM 3.4 API in
  lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp:

  DwarfUnit -> CompileUnit

r264827: Merge Clang r202185:

    Debug info: Generate debug info for variadic functions.
    Paired commit with LLVM.

    rdar://problem/13690847

  This merege includes changes to use the Clang 3.4 API (revisions
  199686 and 200082) in lib/CodeGen/CGDebugInfo.cpp:

  getParamType  -> getArgType
  getNumParams  -> getNumArgs
  getReturnType -> getResultType

r264828: Add patches corresponding to r264826 and r264827

Sponsored by:	DARPA, AFRL

3 files changed, 50 insertions, 28 deletions

diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 97ef687..50f5cc9 100644
--- a/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -1116,6 +1116,22 @@ void CompileUnit::constructTypeDIE(DIE &Buffer, DIDerivedType DTy) {
     addSourceLine(&Buffer, DTy);
 }
 
+/// constructSubprogramArguments - Construct function argument DIEs.
+void CompileUnit::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);
+      }
+    }
+}
+
 /// Return true if the type is appropriately scoped to be contained inside
 /// its own type unit.
 static bool isTypeUnitScoped(DIType Ty, const DwarfDebug *DD) {
@@ -1170,19 +1186,12 @@ void CompileUnit::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();
@@ -1475,13 +1484,7 @@ DIE *CompileUnit::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/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index 69a96df..b9e941e 100644
--- a/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -342,6 +342,9 @@ public:
   void emitHeader(const MCSection *ASection, const MCSymbol *ASectionSym);
 
 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);
 
diff --git a/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d1e1ad1..d922433 100644
--- a/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/contrib/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -404,15 +404,21 @@ DIE *DwarfDebug::updateSubprogramScopeDIE(CompileUnit *SPCU, DISubprogram SP) {
         DIArray Args = SPTy.getTypeArray();
         uint16_t SPTag = SPTy.getTag();
         if (SPTag == dwarf::DW_TAG_subroutine_type)
+          // FIXME: Use DwarfUnit::constructSubprogramArguments() here.
           for (unsigned i = 1, N = Args.getNumElements(); i < N; ++i) {
-            DIE *Arg =
-                SPCU->createAndAddDIE(dwarf::DW_TAG_formal_parameter, *SPDie);
             DIType ATy(Args.getElement(i));
-            SPCU->addType(Arg, ATy);
-            if (ATy.isArtificial())
-              SPCU->addFlag(Arg, dwarf::DW_AT_artificial);
-            if (ATy.isObjectPointer())
-              SPCU->addDIEEntry(SPDie, dwarf::DW_AT_object_pointer, Arg);
+            if (ATy.isUnspecifiedParameter()) {
+              assert(i == N-1 && "ellipsis must be the last argument");
+              SPCU->createAndAddDIE(dwarf::DW_TAG_unspecified_parameters, *SPDie);
+            } else {
+              DIE *Arg =
+                SPCU->createAndAddDIE(dwarf::DW_TAG_formal_parameter, *SPDie);
+              SPCU->addType(Arg, ATy);
+              if (ATy.isArtificial())
+                SPCU->addFlag(Arg, dwarf::DW_AT_artificial);
+              if (ATy.isObjectPointer())
+                SPCU->addDIEEntry(SPDie, dwarf::DW_AT_object_pointer, Arg);
+            }
           }
         DIE *SPDeclDie = SPDie;
         SPDie =
@@ -579,7 +585,7 @@ DIE *DwarfDebug::createScopeChildrenDIE(CompileUnit *TheCU, LexicalScope *Scope,
     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 =
@@ -588,6 +594,16 @@ DIE *DwarfDebug::createScopeChildrenDIE(CompileUnit *TheCU, LexicalScope *Scope,
           if (ArgDV->isObjectPointer()) 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);
   for (unsigned i = 0, N = Variables.size(); i < N; ++i)