DebugInfo: Implement MDLocation::getInlinedAtScope()

Write `MDLocation::getInlinedAtScope()` and use it to re-implement
`DebugLoc::getScopeNode()` (and simplify `DISubprogram::Verify()`).
This follows the inlined-at linked list and returns the scope of the
deepest/last location.

llvm-svn: 233568

llvm/include/llvm/IR/DebugInfoMetadata.h

@@ -949,6 +949,16 @@ public:
     return cast_or_null<MDLocation>(getRawInlinedAt());
   }
 
+  /// \brief Get the scope where this is inlined.
+  ///
+  /// Walk through \a getInlinedAt() and return \a getScope() from the deepest
+  /// location.
+  MDLocalScope *getInlinedAtScope() const {
+    if (auto *IA = getInlinedAt())
+      return IA->getInlinedAtScope();
+    return getScope();
+  }
+
   Metadata *getRawScope() const { return getOperand(0); }
   Metadata *getRawInlinedAt() const {
     if (getNumOperands() == 2)

llvm/lib/IR/DebugInfo.cpp

@@ -349,9 +349,7 @@ bool DISubprogram::Verify() const {
           continue;
 
         // walk the inlined-at scopes
-        while (MDLocation *IA = DL->getInlinedAt())
-          DL = IA;
-        MDScope *Scope = DL->getScope();
+        MDScope *Scope = DL->getInlinedAtScope();
         if (!Scope)
           return false;
         while (!isa<MDSubprogram>(Scope)) {

llvm/lib/IR/DebugLoc.cpp

@@ -33,9 +33,7 @@ void DebugLoc::getScopeAndInlinedAt(MDNode *&Scope, MDNode *&IA) const {
 }
 
 MDNode *DebugLoc::getScopeNode() const {
-  if (MDNode *InlinedAt = getInlinedAt())
-    return DebugLoc::getFromDILocation(InlinedAt).getScopeNode();
-  return getScope();
+  return cast<MDLocation>(Loc)->getInlinedAtScope();
 }
 
 DebugLoc DebugLoc::getFnDebugLoc() const {