Solidify the assumption that a DW_TAG_subprogram's type is a DW_TAG_subroutine_type

There were bits & pieces of code lying around that may've given the
impression that debug info metadata supported the possibility that a
subprogram's type could be specified by a non-subroutine type describing
the return type of a void function. This support was incomplete &
unnecessary. Asserts & API have been changed to make the desired usage
more clear.

llvm-svn: 182532

2 files changed, 18 insertions, 21 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index 7f0c33bb05c..90ca034c976 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -1208,13 +1208,11 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
 
   // Add Return Type.
   DICompositeType SPTy = SP.getType();
-  DIArray Args = SPTy.getTypeArray();
-  unsigned SPTag = SPTy.getTag();
+  assert(SPTy.getTag() == dwarf::DW_TAG_subroutine_type &&
+         "the type of a subprogram should be a subroutine");
 
-  if (Args.getNumElements() == 0 || SPTag != dwarf::DW_TAG_subroutine_type)
-    addType(SPDie, SPTy);
-  else
-    addType(SPDie, DIType(Args.getElement(0)));
+  DIArray Args = SPTy.getTypeArray();
+  addType(SPDie, DIType(Args.getElement(0)));
 
   unsigned VK = SP.getVirtuality();
   if (VK) {
@@ -1232,19 +1230,14 @@ DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram SP) {
 
     // Add arguments. Do not add arguments for subprogram definition. They will
     // be handled while processing variables.
-    DICompositeType SPTy = SP.getType();
-    DIArray Args = SPTy.getTypeArray();
-    unsigned SPTag = SPTy.getTag();
-
-    if (SPTag == dwarf::DW_TAG_subroutine_type)
-      for (unsigned i = 1, N =  Args.getNumElements(); i < N; ++i) {
-        DIE *Arg = new DIE(dwarf::DW_TAG_formal_parameter);
-        DIType ATy = DIType(Args.getElement(i));
-        addType(Arg, ATy);
-        if (ATy.isArtificial())
-          addFlag(Arg, dwarf::DW_AT_artificial);
-        SPDie->addChild(Arg);
-      }
+    for (unsigned i = 1, N =  Args.getNumElements(); i < N; ++i) {
+      DIE *Arg = new DIE(dwarf::DW_TAG_formal_parameter);
+      DIType ATy = DIType(Args.getElement(i));
+      addType(Arg, ATy);
+      if (ATy.isArtificial())
+        addFlag(Arg, dwarf::DW_AT_artificial);
+      SPDie->addChild(Arg);
+    }
   }
 
   if (SP.isArtificial())
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index 1c799452754..8edc6a0f10c 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -969,13 +969,15 @@ DISubprogram DIBuilder::createFunction(DIDescriptor Context,
                                        StringRef Name,
                                        StringRef LinkageName,
                                        DIFile File, unsigned LineNo,
-                                       DIType Ty,
+                                       DICompositeType Ty,
                                        bool isLocalToUnit, bool isDefinition,
                                        unsigned ScopeLine,
                                        unsigned Flags, bool isOptimized,
                                        Function *Fn,
                                        MDNode *TParams,
                                        MDNode *Decl) {
+  assert(Ty.getTag() == dwarf::DW_TAG_subroutine_type &&
+         "function types should be subroutines");
   Value *TElts[] = { GetTagConstant(VMContext, DW_TAG_base_type) };
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_subprogram),
@@ -1014,7 +1016,7 @@ DISubprogram DIBuilder::createMethod(DIDescriptor Context,
                                      StringRef Name,
                                      StringRef LinkageName,
                                      DIFile F,
-                                     unsigned LineNo, DIType Ty,
+                                     unsigned LineNo, DICompositeType Ty,
                                      bool isLocalToUnit,
                                      bool isDefinition,
                                      unsigned VK, unsigned VIndex,
@@ -1023,6 +1025,8 @@ DISubprogram DIBuilder::createMethod(DIDescriptor Context,
                                      bool isOptimized,
                                      Function *Fn,
                                      MDNode *TParam) {
+  assert(Ty.getTag() == dwarf::DW_TAG_subroutine_type &&
+         "function types should be subroutines");
   Value *TElts[] = { GetTagConstant(VMContext, DW_TAG_base_type) };
   Value *Elts[] = {
     GetTagConstant(VMContext, dwarf::DW_TAG_subprogram),