97dd8e3c4f
This commit heavily refactors and simplifies the small and trivial checker `apiModeling.llvm.ReturnValue`, which is responsible for modeling the peculiar coding convention that in the LLVM/Clang codebase certain Error() methods always return true. Changes included in this commit: - The call description mode is now specified explicitly (this is not the most significant change, but it was the original reason for touching this checker). - Previously the code provided support for modeling functions that always return `false`; but there was no need for that, so this commit hardcodes that the return value is `true`. - The overcomplicated constraint/state handling logic was simplified. - The separate `checkEndFunction` callback was removed to simplify the code. Admittedly this means that the note tag for the "<method> returns false, breaking the convention" case is placed on the method call instead of the `return` statement; but that case will _never_ appear in practice, so this difference is mostly academical. - The text of the note tags was clarified. - The descriptions in the header comment and Checkers.td were clarified. - Some minor cleanup was applied in the associated test file. This change is very close to NFC because it only affects a hidden `apiModeling.llvm` checker that's only relevant during the analysis of the LLVM/Clang codebase, and even there it doesn't affect the normal behavior of the checker.
92 lines
2.4 KiB
C++
92 lines
2.4 KiB
C++
// RUN: %clang_analyze_cc1 \
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// RUN: -analyzer-checker=core,apiModeling.llvm.ReturnValue \
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// RUN: -analyzer-output=text -verify %s
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struct Foo { int Field; };
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bool problem();
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void doSomething();
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// Test the normal case when the implementation of MCAsmParser::Error() (one of
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// the methods modeled by this checker) is opaque.
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namespace test_normal {
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struct MCAsmParser {
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static bool Error();
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};
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bool parseFoo(Foo &F) {
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if (problem()) {
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// expected-note@-1 {{Assuming the condition is false}}
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// expected-note@-2 {{Taking false branch}}
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return MCAsmParser::Error();
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}
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F.Field = 0;
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// expected-note@-1 {{The value 0 is assigned to 'F.Field'}}
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return false;
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}
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bool parseFile() {
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Foo F;
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if (parseFoo(F)) {
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// expected-note@-1 {{Calling 'parseFoo'}}
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// expected-note@-2 {{Returning from 'parseFoo'}}
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// expected-note@-3 {{Taking false branch}}
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return true;
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}
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// The following expression would produce the false positive report
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// "The left operand of '==' is a garbage value"
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// without the modeling done by apiModeling.llvm.ReturnValue:
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if (F.Field == 0) {
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// expected-note@-1 {{Field 'Field' is equal to 0}}
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// expected-note@-2 {{Taking true branch}}
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doSomething();
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}
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// Trigger a zero division to get path notes:
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(void)(1 / F.Field);
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// expected-warning@-1 {{Division by zero}}
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// expected-note@-2 {{Division by zero}}
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return false;
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}
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} // namespace test_normal
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// Sanity check for the highly unlikely case where the implementation of the
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// method breaks the convention.
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namespace test_break {
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struct MCAsmParser {
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static bool Error() {
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return false;
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}
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};
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bool parseFoo(Foo &F) {
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if (problem()) {
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// expected-note@-1 {{Assuming the condition is false}}
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// expected-note@-2 {{Taking false branch}}
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return !MCAsmParser::Error();
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}
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F.Field = 0;
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// expected-note@-1 {{The value 0 is assigned to 'F.Field'}}
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return MCAsmParser::Error();
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// expected-note@-1 {{'MCAsmParser::Error' returned false, breaking the convention that it always returns true}}
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}
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bool parseFile() {
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Foo F;
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if (parseFoo(F)) {
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// expected-note@-1 {{Calling 'parseFoo'}}
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// expected-note@-2 {{Returning from 'parseFoo'}}
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// expected-note@-3 {{Taking false branch}}
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return true;
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}
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(void)(1 / F.Field);
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// expected-warning@-1 {{Division by zero}}
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// expected-note@-2 {{Division by zero}}
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return false;
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}
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} // namespace test_break
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