Selector::getIdentifierInfoForSlot() can return NULL values, a fact

that was ignored in a few places (most notably, code
completion). Introduce Selector::getNameForSlot() for the common case
where we only care about the name. Audit all uses of
getIdentifierInfoForSlot(), switching many over to getNameForSlot(),
fixing a few crashers.

Fixed <rdar://problem/8939352>, a code-completion crasher.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125977 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 21 insertions, 22 deletions

diff --git a/lib/AST/DeclarationName.cpp b/lib/AST/DeclarationName.cpp
index ac3989bbb8..cef54e97c9 100644
--- a/lib/AST/DeclarationName.cpp
+++ b/lib/AST/DeclarationName.cpp
@@ -94,10 +94,8 @@ int DeclarationName::compare(DeclarationName LHS, DeclarationName RHS) {
     Selector RHSSelector = RHS.getObjCSelector();
     unsigned LN = LHSSelector.getNumArgs(), RN = RHSSelector.getNumArgs();
     for (unsigned I = 0, N = std::min(LN, RN); I != N; ++I) {
-      IdentifierInfo *LHSId = LHSSelector.getIdentifierInfoForSlot(I);
-      IdentifierInfo *RHSId = RHSSelector.getIdentifierInfoForSlot(I);
-        
-      switch (LHSId->getName().compare(RHSId->getName())) {
+      switch (LHSSelector.getNameForSlot(I).compare(
+                                               RHSSelector.getNameForSlot(I))) {
       case -1: return true;
       case 1: return false;
       default: break;
diff --git a/lib/AST/StmtPrinter.cpp b/lib/AST/StmtPrinter.cpp
index a67e269790..1cdd220881 100644
--- a/lib/AST/StmtPrinter.cpp
+++ b/lib/AST/StmtPrinter.cpp
@@ -1311,7 +1311,7 @@ void StmtPrinter::VisitObjCMessageExpr(ObjCMessageExpr *Mess) {
   OS << ' ';
   Selector selector = Mess->getSelector();
   if (selector.isUnarySelector()) {
-    OS << selector.getIdentifierInfoForSlot(0)->getName();
+    OS << selector.getNameForSlot(0);
   } else {
     for (unsigned i = 0, e = Mess->getNumArgs(); i != e; ++i) {
       if (i < selector.getNumArgs()) {
diff --git a/lib/Basic/IdentifierTable.cpp b/lib/Basic/IdentifierTable.cpp
index 48a5f49914..ef11d658ed 100644
--- a/lib/Basic/IdentifierTable.cpp
+++ b/lib/Basic/IdentifierTable.cpp
@@ -326,6 +326,11 @@ IdentifierInfo *Selector::getIdentifierInfoForSlot(unsigned argIndex) const {
   return SI->getIdentifierInfoForSlot(argIndex);
 }
 
+llvm::StringRef Selector::getNameForSlot(unsigned int argIndex) const {
+  IdentifierInfo *II = getIdentifierInfoForSlot(argIndex);
+  return II? II->getName() : llvm::StringRef();
+}
+
 std::string MultiKeywordSelector::getName() const {
   llvm::SmallString<256> Str;
   llvm::raw_svector_ostream OS(Str);
diff --git a/lib/Sema/SemaCodeComplete.cpp b/lib/Sema/SemaCodeComplete.cpp
index 703734e247..a65d5fd6fc 100644
--- a/lib/Sema/SemaCodeComplete.cpp
+++ b/lib/Sema/SemaCodeComplete.cpp
@@ -2391,11 +2391,11 @@ CodeCompletionResult::CreateCodeCompletionString(Sema &S,
     Selector Sel = Method->getSelector();
     if (Sel.isUnarySelector()) {
       Result.AddTypedTextChunk(Result.getAllocator().CopyString(
-                                  Sel.getIdentifierInfoForSlot(0)->getName()));
+                                  Sel.getNameForSlot(0)));
       return Result.TakeString();
     }
 
-    std::string SelName = Sel.getIdentifierInfoForSlot(0)->getName().str();
+    std::string SelName = Sel.getNameForSlot(0).str();
     SelName += ':';
     if (StartParameter == 0)
       Result.AddTypedTextChunk(Result.getAllocator().CopyString(SelName));
@@ -4531,10 +4531,10 @@ static ObjCMethodDecl *AddSuperSendCompletion(Sema &S, bool NeedSuperKeyword,
   if (Sel.isUnarySelector()) {
     if (NeedSuperKeyword)
       Builder.AddTextChunk(Builder.getAllocator().CopyString(
-                                  Sel.getIdentifierInfoForSlot(0)->getName()));
+                                  Sel.getNameForSlot(0)));
     else
       Builder.AddTypedTextChunk(Builder.getAllocator().CopyString(
-                                   Sel.getIdentifierInfoForSlot(0)->getName()));
+                                   Sel.getNameForSlot(0)));
   } else {
     ObjCMethodDecl::param_iterator CurP = CurMethod->param_begin();
     for (unsigned I = 0, N = Sel.getNumArgs(); I != N; ++I, ++CurP) {
@@ -4544,17 +4544,17 @@ static ObjCMethodDecl *AddSuperSendCompletion(Sema &S, bool NeedSuperKeyword,
       if (I < NumSelIdents)
         Builder.AddInformativeChunk(
                    Builder.getAllocator().CopyString(
-                      Sel.getIdentifierInfoForSlot(I)->getName().str() + ":"));
+                                                 Sel.getNameForSlot(I) + ":"));
       else if (NeedSuperKeyword || I > NumSelIdents) {
         Builder.AddTextChunk(
                  Builder.getAllocator().CopyString(
-                      Sel.getIdentifierInfoForSlot(I)->getName().str() + ":"));
+                                                  Sel.getNameForSlot(I) + ":"));
         Builder.AddPlaceholderChunk(Builder.getAllocator().CopyString(
                                          (*CurP)->getIdentifier()->getName()));
       } else {
         Builder.AddTypedTextChunk(
                   Builder.getAllocator().CopyString(
-                      Sel.getIdentifierInfoForSlot(I)->getName().str() + ":"));
+                                                  Sel.getNameForSlot(I) + ":"));
         Builder.AddPlaceholderChunk(Builder.getAllocator().CopyString(
                                          (*CurP)->getIdentifier()->getName())); 
       }
@@ -5002,7 +5002,7 @@ void Sema::CodeCompleteObjCSelector(Scope *S, IdentifierInfo **SelIdents,
     CodeCompletionBuilder Builder(Results.getAllocator());
     if (Sel.isUnarySelector()) {
       Builder.AddTypedTextChunk(Builder.getAllocator().CopyString(
-                                   Sel.getIdentifierInfoForSlot(0)->getName()));
+                                                       Sel.getNameForSlot(0)));
       Results.AddResult(Builder.TakeString());
       continue;
     }
@@ -5017,7 +5017,7 @@ void Sema::CodeCompleteObjCSelector(Scope *S, IdentifierInfo **SelIdents,
         }
       }
       
-      Accumulator += Sel.getIdentifierInfoForSlot(I)->getName().str();
+      Accumulator += Sel.getNameForSlot(I).str();
       Accumulator += ':';
     }
     Builder.AddTypedTextChunk(Builder.getAllocator().CopyString( Accumulator));
@@ -6115,7 +6115,7 @@ void Sema::CodeCompleteObjCMethodDecl(Scope *S,
 
     // Add the first part of the selector to the pattern.
     Builder.AddTypedTextChunk(Builder.getAllocator().CopyString(
-                                   Sel.getIdentifierInfoForSlot(0)->getName()));
+                                                       Sel.getNameForSlot(0)));
 
     // Add parameters to the pattern.
     unsigned I = 0;
@@ -6128,9 +6128,7 @@ void Sema::CodeCompleteObjCMethodDecl(Scope *S,
       else if (I < Sel.getNumArgs()) {
         Builder.AddChunk(CodeCompletionString::CK_HorizontalSpace);
         Builder.AddTypedTextChunk(
-                          Builder.getAllocator().CopyString(
-                                   (Sel.getIdentifierInfoForSlot(I)->getName()
-                                    + ":").str()));
+                Builder.getAllocator().CopyString(Sel.getNameForSlot(I) + ":"));
       } else
         break;
 
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index d5e6e77c3e..7e6eee7fb7 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9487,13 +9487,11 @@ void Sema::DiagnoseAssignmentAsCondition(Expr *E) {
       Selector Sel = ME->getSelector();
 
       // self = [<foo> init...]
-      if (isSelfExpr(Op->getLHS())
-          && Sel.getIdentifierInfoForSlot(0)->getName().startswith("init"))
+      if (isSelfExpr(Op->getLHS()) && Sel.getNameForSlot(0).startswith("init"))
         diagnostic = diag::warn_condition_is_idiomatic_assignment;
 
       // <foo> = [<bar> nextObject]
-      else if (Sel.isUnarySelector() &&
-               Sel.getIdentifierInfoForSlot(0)->getName() == "nextObject")
+      else if (Sel.isUnarySelector() && Sel.getNameForSlot(0) == "nextObject")
         diagnostic = diag::warn_condition_is_idiomatic_assignment;
     }