[clang-tidy] Make 'modernize-use-nullptr' check ignores NULL marcos used in other macros.

[alexfh]

Adding Benjamin as a reviewer, since I'm on vacation.

[bkramer]

Patch looks good, only one cosmetic comment.

clang-tidy/modernize/UseNullptrCheck.cpp

232

This doesn't look clang-formatted.

[hokein]

Format code.

clang-tidy/modernize/UseNullptrCheck.cpp

bool VisitStmt(Stmt *S) {
     // If the location comes from a macro arg expansion, *all* uses of that
     // arg must be checked to result in NullTo(Member)Pointer casts.
     //
     // If the location comes from a macro body expansion, check to see if its
     // coming from one of the allowed 'NULL' macros.
     if (SM.isMacroArgExpansion(StartLoc) && SM.isMacroArgExpansion(EndLoc)) {
       SourceLocation FileLocStart = SM.getFileLoc(StartLoc),
                      FileLocEnd = SM.getFileLoc(EndLoc);
+      SourceLocation ImmediateMarcoArgLoc, MacroLoc;
+      // Skip NULL macros used in macro.
+      if (!getMacroAndArgLocations(StartLoc, ImmediateMarcoArgLoc, MacroLoc)
+          || ImmediateMarcoArgLoc != FileLocStart)
+        return skipSubTree();
+
       if (isReplaceableRange(FileLocStart, FileLocEnd, SM) &&
           allArgUsesValid(C)) {
         replaceWithNullptr(Check, SM, FileLocStart, FileLocEnd);
       }
       return skipSubTree();
     }
 
     if (SM.isMacroBodyExpansion(StartLoc) && SM.isMacroBodyExpansion(EndLoc)) {

test/clang-tidy/modernize-use-nullptr.cpp

#define assert2 assert1
   assert2(p == 0);
   // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: use nullptr
   // CHECK-FIXES: assert2(p == nullptr);
   assert2(p == NULL);
   // CHECK-MESSAGES: :[[@LINE-1]]:16: warning: use nullptr
   // CHECK-FIXES: assert2(p == nullptr);
 #undef assert2
 #undef assert1
+
+#define ASSERT_EQ(a, b) a == b
+#define ASSERT_NULL(x) ASSERT_EQ(static_cast<void *>(NULL), x)
+  int *pp;
+  ASSERT_NULL(pp);
+  ASSERT_NULL(NULL);
+  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: use nullptr
+  // CHECK-FIXES: ASSERT_NULL(nullptr);
+#undef ASSERT_NULL
+#undef ASSERT_EQ
 }
 
 // One of the ancestor of the cast is a NestedNameSpecifierLoc.
 class NoDef;
 char function(NoDef *p);
 #define F(x) (sizeof(function(x)) == 1)
 template<class T, T t>
 class C {};
 C<bool, F(0)> c;
 // CHECK-MESSAGES: :[[@LINE-1]]:11: warning: use nullptr
 // CHECK-FIXES: C<bool, F(nullptr)> c;
 #undef F