-Wempty-body: fix false negative triggered by macros

When if statement condition ended in a macro:

    if (ptr == NULL);

the check used to consider the definition location of NULL, instead of the
current line.

Patch by Manasij Mukherjee.

llvm-svn: 232295

clang/lib/Sema/SemaChecking.cpp

@@ -8625,7 +8625,7 @@ bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr,
 
   // Get line numbers of statement and body.
   bool StmtLineInvalid;
-  unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc,
+  unsigned StmtLine = SourceMgr.getPresumedLineNumber(StmtLoc,
                                                       &StmtLineInvalid);
   if (StmtLineInvalid)
     return false;

clang/test/SemaCXX/warn-empty-body.cpp

@@ -4,10 +4,17 @@ void a(int i);
 int b();
 int c();
 
+#define MACRO_A 0
+
 void test1(int x, int y) {
   while(true) {
     if (x); // expected-warning {{if statement has empty body}} expected-note{{put the semicolon on a separate line to silence this warning}}
 
+    // Check that we handle conditions that start or end with a macro
+    // correctly.
+    if (x == MACRO_A); // expected-warning {{if statement has empty body}} expected-note{{put the semicolon on a separate line to silence this warning}}
+    if (MACRO_A == x); // expected-warning {{if statement has empty body}} expected-note{{put the semicolon on a separate line to silence this warning}}
+
     int i;
     // PR11329
     for (i = 0; i < x; i++); { // expected-warning{{for loop has empty body}} expected-note{{put the semicolon on a separate line to silence this warning}}