clang/test/Analysis/return-value-guaranteed.cpp

   1 // RUN: %clang_analyze_cc1 \
   2 // RUN:  -analyzer-checker=core,apiModeling.llvm.ReturnValue \
   3 // RUN:  -analyzer-output=text -verify=class %s
   4
   5 struct Foo { int Field; };
   6 bool problem();
   7 void doSomething();
   8
   9 // We predefined the return value of 'MCAsmParser::Error' as true and we cannot
  10 // take the false-branches which leads to a "garbage value" false positive.
  11 namespace test_classes {
  12 struct MCAsmParser {
  13   static bool Error();
  14 };
  15
  16 bool parseFoo(Foo &F) {
  17   if (problem()) {
  18     // class-note@-1 {{Assuming the condition is false}}
  19     // class-note@-2 {{Taking false branch}}
  20     return MCAsmParser::Error();
  21   }
  22
  23   F.Field = 0;
  24   // class-note@-1 {{The value 0 is assigned to 'F.Field'}}
  25   return !MCAsmParser::Error();
  26   // class-note@-1 {{'MCAsmParser::Error' returns true}}
  27 }
  28
  29 bool parseFile() {
  30   Foo F;
  31   if (parseFoo(F)) {
  32     // class-note@-1 {{Calling 'parseFoo'}}
  33     // class-note@-2 {{Returning from 'parseFoo'}}
  34     // class-note@-3 {{Taking false branch}}
  35     return true;
  36   }
  37
  38   if (F.Field == 0) {
  39     // class-note@-1 {{Field 'Field' is equal to 0}}
  40     // class-note@-2 {{Taking true branch}}
  41
  42     // no-warning: "The left operand of '==' is a garbage value" was here.
  43     doSomething();
  44   }
  45
  46   (void)(1 / F.Field);
  47   // class-warning@-1 {{Division by zero}}
  48   // class-note@-2 {{Division by zero}}
  49   return false;
  50 }
  51 } // namespace test_classes
  52
  53
  54 // We predefined 'MCAsmParser::Error' as returning true, but now it returns
  55 // false, which breaks our invariant. Test the notes.
  56 namespace test_break {
  57 struct MCAsmParser {
  58   static bool Error() {
  59     return false; // class-note {{'MCAsmParser::Error' returns false}}
  60   }
  61 };
  62
  63 bool parseFoo(Foo &F) {
  64   if (problem()) {
  65     // class-note@-1 {{Assuming the condition is false}}
  66     // class-note@-2 {{Taking false branch}}
  67     return !MCAsmParser::Error();
  68   }
  69
  70   F.Field = 0;
  71   // class-note@-1 {{The value 0 is assigned to 'F.Field'}}
  72   return MCAsmParser::Error();
  73   // class-note@-1 {{Calling 'MCAsmParser::Error'}}
  74   // class-note@-2 {{Returning from 'MCAsmParser::Error'}}
  75 }
  76
  77 bool parseFile() {
  78   Foo F;
  79   if (parseFoo(F)) {
  80     // class-note@-1 {{Calling 'parseFoo'}}
  81     // class-note@-2 {{Returning from 'parseFoo'}}
  82     // class-note@-3 {{Taking false branch}}
  83     return true;
  84   }
  85
  86   (void)(1 / F.Field);
  87   // class-warning@-1 {{Division by zero}}
  88   // class-note@-2 {{Division by zero}}
  89   return false;
  90 }
  91 } // namespace test_classes