r210372 - Add -Wtautological-undefined-compare and -Wundefined-bool-conversion warnings
Richard Trieu
rtrieu at google.com
Mon Jun 9 13:04:01 PDT 2014
Sorry for the breakages. I am getting a patch together to fix these issues.
On Mon, Jun 9, 2014 at 1:07 AM, Kostya Serebryany <kcc at google.com> wrote:
> Meanwhile, all our bots are red due to this commit.
>
>
> On Mon, Jun 9, 2014 at 3:59 AM, Gabriel Dos Reis <
> gdr at integrable-solutions.net> wrote:
>
>>
>>
>>
>> On Sun, Jun 8, 2014 at 4:20 PM, NAKAMURA Takumi <geek4civic at gmail.com>
>> wrote:
>>
>>> We see warnings in the llvm/clang tree. Shall we honor them?
>>>
>>> /home/tnakamura/fio/ninja/llvm-project/llvm/lib/IR/AsmWriter.cpp:2159:8:
>>> error: 'this' pointer cannot be null in well-defined C++ code; pointer
>>> may be assumed always converted to true
>>> [-Werror,-Wundefined-bool-conversion]
>>> if (!this) {
>>> ~^~~~
>>> llvm/lib/IR/AsmWriter.cpp:2175:8: error: 'this' pointer cannot be null
>>> in well-defined C++ code; pointer may be assumed always converted to
>>> true [-Werror,-Wundefined-bool-conversion]
>>> if (!this) {
>>> ~^~~~
>>>
>>> clang/lib/AST/StmtPrinter.cpp:2028:7: error: 'this' pointer cannot be
>>> null in well-defined C++ code; comparison may be assumed to always
>>> evaluate to false [-Werror,-Wtautological-undefined-compare]
>>> if (this == nullptr) {
>>> ^~~~ ~~~~~~~
>>>
>>
>> Interesting. Looks like potentially a source of bug in the existing code
>> :-)
>>
>> -- Gaby
>>
>>
>>
>>>
>>> 2014-06-07 6:39 GMT+09:00 Richard Trieu <rtrieu at google.com>:
>>> > Author: rtrieu
>>> > Date: Fri Jun 6 16:39:26 2014
>>> > New Revision: 210372
>>> >
>>> > URL: http://llvm.org/viewvc/llvm-project?rev=210372&view=rev
>>> > Log:
>>> > Add -Wtautological-undefined-compare and -Wundefined-bool-conversion
>>> warnings
>>> > to detect underfined behavior involving pointers.
>>> >
>>> > Added:
>>> > cfe/trunk/test/SemaCXX/warn-tautological-undefined-compare.cpp
>>> > cfe/trunk/test/SemaCXX/warn-undefined-bool-conversion.cpp
>>> > Modified:
>>> > cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>>> > cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>> > cfe/trunk/lib/Sema/SemaChecking.cpp
>>> > cfe/trunk/test/Analysis/inlining/path-notes.cpp
>>> > cfe/trunk/test/Analysis/misc-ps-region-store.cpp
>>> > cfe/trunk/test/Analysis/reference.cpp
>>> > cfe/trunk/test/Analysis/stack-addr-ps.cpp
>>> >
>>> > Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=210372&r1=210371&r2=210372&view=diff
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
>>> > +++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Fri Jun 6
>>> 16:39:26 2014
>>> > @@ -38,7 +38,9 @@ def LiteralConversion : DiagGroup<"liter
>>> > def StringConversion : DiagGroup<"string-conversion">;
>>> > def SignConversion : DiagGroup<"sign-conversion">;
>>> > def PointerBoolConversion : DiagGroup<"pointer-bool-conversion">;
>>> > -def BoolConversion : DiagGroup<"bool-conversion", [
>>> PointerBoolConversion ] >;
>>> > +def UndefinedBoolConversion : DiagGroup<"undefined-bool-conversion">;
>>> > +def BoolConversion : DiagGroup<"bool-conversion",
>>> [PointerBoolConversion,
>>> > +
>>> UndefinedBoolConversion]>;
>>> > def IntConversion : DiagGroup<"int-conversion">;
>>> > def EnumConversion : DiagGroup<"enum-conversion">;
>>> > def FloatConversion : DiagGroup<"float-conversion">;
>>> > @@ -298,10 +300,12 @@ def StrncatSize : DiagGroup<"strncat-siz
>>> > def TautologicalOutOfRangeCompare :
>>> DiagGroup<"tautological-constant-out-of-range-compare">;
>>> > def TautologicalPointerCompare :
>>> DiagGroup<"tautological-pointer-compare">;
>>> > def TautologicalOverlapCompare :
>>> DiagGroup<"tautological-overlap-compare">;
>>> > +def TautologicalUndefinedCompare :
>>> DiagGroup<"tautological-undefined-compare">;
>>> > def TautologicalCompare : DiagGroup<"tautological-compare",
>>> > [TautologicalOutOfRangeCompare,
>>> > TautologicalPointerCompare,
>>> > - TautologicalOverlapCompare]>;
>>> > + TautologicalOverlapCompare,
>>> > + TautologicalUndefinedCompare]>;
>>> > def HeaderHygiene : DiagGroup<"header-hygiene">;
>>> > def DuplicateDeclSpecifier : DiagGroup<"duplicate-decl-specifier">;
>>> > def CompareDistinctPointerType :
>>> DiagGroup<"compare-distinct-pointer-types">;
>>> >
>>> > Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=210372&r1=210371&r2=210372&view=diff
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
>>> > +++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Jun 6
>>> 16:39:26 2014
>>> > @@ -2400,10 +2400,27 @@ def warn_impcast_pointer_to_bool : Warni
>>> > "address of%select{| function| array}0 '%1' will always evaluate
>>> to "
>>> > "'true'">,
>>> > InGroup<PointerBoolConversion>;
>>> > +def warn_this_bool_conversion : Warning<
>>> > + "'this' pointer cannot be null in well-defined C++ code; pointer
>>> may be "
>>> > + "assumed always converted to true">,
>>> InGroup<UndefinedBoolConversion>;
>>> > +def warn_address_of_reference_bool_conversion : Warning<
>>> > + "reference cannot be bound to dereferenced null pointer in
>>> well-defined C++ "
>>> > + "code; pointer may be assumed always converted to true">,
>>> > + InGroup<UndefinedBoolConversion>;
>>> > +
>>> > def warn_null_pointer_compare : Warning<
>>> > "comparison of %select{address of|function|array}0 '%1'
>>> %select{not |}2"
>>> > "equal to a null pointer is always %select{true|false}2">,
>>> > InGroup<TautologicalPointerCompare>;
>>> > +def warn_this_null_compare : Warning<
>>> > + "'this' pointer cannot be null in well-defined C++ code; comparison
>>> may be "
>>> > + "assumed to always evaluate to %select{true|false}0">,
>>> > + InGroup<TautologicalUndefinedCompare>;
>>> > +def warn_address_of_reference_null_compare : Warning<
>>> > + "reference cannot be bound to dereferenced null pointer in
>>> well-defined C++ "
>>> > + "code; comparison may be assumed to always evaluate to "
>>> > + "%select{true|false}0">,
>>> > + InGroup<TautologicalUndefinedCompare>;
>>> >
>>> > def note_function_warning_silence : Note<
>>> > "prefix with the address-of operator to silence this warning">;
>>> >
>>> > Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=210372&r1=210371&r2=210372&view=diff
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
>>> > +++ cfe/trunk/lib/Sema/SemaChecking.cpp Fri Jun 6 16:39:26 2014
>>> > @@ -6189,6 +6189,13 @@ void Sema::DiagnoseAlwaysNonNullPointer(
>>> >
>>> > const bool IsCompare = NullKind != Expr::NPCK_NotNull;
>>> >
>>> > + if (isa<CXXThisExpr>(E)) {
>>> > + unsigned DiagID = IsCompare ? diag::warn_this_null_compare
>>> > + : diag::warn_this_bool_conversion;
>>> > + Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range <<
>>> IsEqual;
>>> > + return;
>>> > + }
>>> > +
>>> > bool IsAddressOf = false;
>>> >
>>> > if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
>>> > @@ -6218,9 +6225,14 @@ void Sema::DiagnoseAlwaysNonNullPointer(
>>> > // Address of function is used to silence the function warning.
>>> > if (IsFunction)
>>> > return;
>>> > - // Address of reference can be null.
>>> > - if (T->isReferenceType())
>>> > +
>>> > + if (T->isReferenceType()) {
>>> > + unsigned DiagID = IsCompare
>>> > + ?
>>> diag::warn_address_of_reference_null_compare
>>> > + :
>>> diag::warn_address_of_reference_bool_conversion;
>>> > + Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range
>>> << IsEqual;
>>> > return;
>>> > + }
>>> > }
>>> >
>>> > // Found nothing.
>>> >
>>> > Modified: cfe/trunk/test/Analysis/inlining/path-notes.cpp
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/inlining/path-notes.cpp?rev=210372&r1=210371&r2=210372&view=diff
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/test/Analysis/inlining/path-notes.cpp (original)
>>> > +++ cfe/trunk/test/Analysis/inlining/path-notes.cpp Fri Jun 6
>>> 16:39:26 2014
>>> > @@ -1,5 +1,5 @@
>>> > -// RUN: %clang_cc1 -analyze -analyzer-checker=core
>>> -analyzer-output=text -analyzer-config c++-inlining=destructors -std=c++11
>>> -verify %s
>>> > -// RUN: %clang_cc1 -analyze -analyzer-checker=core
>>> -analyzer-output=plist-multi-file -analyzer-config c++-inlining=destructors
>>> -std=c++11 -analyzer-config path-diagnostics-alternate=false %s -o %t.plist
>>> > +// RUN: %clang_cc1 -analyze -analyzer-checker=core
>>> -analyzer-output=text -analyzer-config c++-inlining=destructors -std=c++11
>>> -verify -Wno-tautological-undefined-compare %s
>>> > +// RUN: %clang_cc1 -analyze -analyzer-checker=core
>>> -analyzer-output=plist-multi-file -analyzer-config c++-inlining=destructors
>>> -std=c++11 -analyzer-config path-diagnostics-alternate=false %s -o %t.plist
>>> -Wno-tautological-undefined-compare
>>> > // RUN: FileCheck --input-file=%t.plist %s
>>> >
>>> > class Foo {
>>> >
>>> > Modified: cfe/trunk/test/Analysis/misc-ps-region-store.cpp
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/misc-ps-region-store.cpp?rev=210372&r1=210371&r2=210372&view=diff
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/test/Analysis/misc-ps-region-store.cpp (original)
>>> > +++ cfe/trunk/test/Analysis/misc-ps-region-store.cpp Fri Jun 6
>>> 16:39:26 2014
>>> > @@ -1,5 +1,5 @@
>>> > -// RUN: %clang_cc1 -triple i386-apple-darwin9 -analyze
>>> -analyzer-checker=core,alpha.core,debug.ExprInspection
>>> -analyzer-store=region -verify -fblocks -analyzer-opt-analyze-nested-blocks
>>> %s -fexceptions -fcxx-exceptions
>>> > -// RUN: %clang_cc1 -triple x86_64-apple-darwin9 -analyze
>>> -analyzer-checker=core,alpha.core,debug.ExprInspection
>>> -analyzer-store=region -verify -fblocks -analyzer-opt-analyze-nested-blocks
>>> %s -fexceptions -fcxx-exceptions
>>> > +// RUN: %clang_cc1 -triple i386-apple-darwin9 -analyze
>>> -analyzer-checker=core,alpha.core,debug.ExprInspection
>>> -analyzer-store=region -verify -fblocks -analyzer-opt-analyze-nested-blocks
>>> %s -fexceptions -fcxx-exceptions -Wno-tautological-undefined-compare
>>> > +// RUN: %clang_cc1 -triple x86_64-apple-darwin9 -analyze
>>> -analyzer-checker=core,alpha.core,debug.ExprInspection
>>> -analyzer-store=region -verify -fblocks -analyzer-opt-analyze-nested-blocks
>>> %s -fexceptions -fcxx-exceptions -Wno-tautological-undefined-compare
>>> >
>>> > void clang_analyzer_warnIfReached();
>>> >
>>> >
>>> > Modified: cfe/trunk/test/Analysis/reference.cpp
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/reference.cpp?rev=210372&r1=210371&r2=210372&view=diff
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/test/Analysis/reference.cpp (original)
>>> > +++ cfe/trunk/test/Analysis/reference.cpp Fri Jun 6 16:39:26 2014
>>> > @@ -1,4 +1,4 @@
>>> > -// RUN: %clang_cc1 -analyze
>>> -analyzer-checker=core,alpha.core,debug.ExprInspection
>>> -analyzer-store=region -analyzer-constraints=range -verify
>>> -Wno-null-dereference %s
>>> > +// RUN: %clang_cc1 -analyze
>>> -analyzer-checker=core,alpha.core,debug.ExprInspection
>>> -analyzer-store=region -analyzer-constraints=range -verify
>>> -Wno-null-dereference -Wno-tautological-undefined-compare %s
>>> >
>>> > void clang_analyzer_eval(bool);
>>> >
>>> >
>>> > Modified: cfe/trunk/test/Analysis/stack-addr-ps.cpp
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/stack-addr-ps.cpp?rev=210372&r1=210371&r2=210372&view=diff
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/test/Analysis/stack-addr-ps.cpp (original)
>>> > +++ cfe/trunk/test/Analysis/stack-addr-ps.cpp Fri Jun 6 16:39:26 2014
>>> > @@ -1,4 +1,4 @@
>>> > -// RUN: %clang_cc1 -analyze -analyzer-checker=core
>>> -analyzer-store=region -verify %s
>>> > +// RUN: %clang_cc1 -analyze -analyzer-checker=core
>>> -analyzer-store=region -verify %s -Wno-undefined-bool-conversion
>>> >
>>> > typedef __INTPTR_TYPE__ intptr_t;
>>> >
>>> >
>>> > Added: cfe/trunk/test/SemaCXX/warn-tautological-undefined-compare.cpp
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-tautological-undefined-compare.cpp?rev=210372&view=auto
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/test/SemaCXX/warn-tautological-undefined-compare.cpp
>>> (added)
>>> > +++ cfe/trunk/test/SemaCXX/warn-tautological-undefined-compare.cpp Fri
>>> Jun 6 16:39:26 2014
>>> > @@ -0,0 +1,34 @@
>>> > +// RUN: %clang_cc1 -fsyntax-only -verify %s
>>> > +// RUN: %clang_cc1 -fsyntax-only -verify
>>> -Wtautological-undefined-compare %s
>>> > +// RUN: %clang_cc1 -fsyntax-only -verify -Wno-tautological-compare
>>> -Wtautological-undefined-compare %s
>>> > +// RUN: %clang_cc1 -fsyntax-only -verify -Wtautological-compare %s
>>> > +
>>> > +void test1(int &x) {
>>> > + if (x == 1) { }
>>> > + if (&x == 0) { }
>>> > + // expected-warning at -1{{reference cannot be bound to dereferenced
>>> null pointer in well-defined C++ code; comparison may be assumed to always
>>> evaluate to false}}
>>> > + if (&x != 0) { }
>>> > + // expected-warning at -1{{reference cannot be bound to dereferenced
>>> null pointer in well-defined C++ code; comparison may be assumed to always
>>> evaluate to true}}
>>> > +}
>>> > +
>>> > +class test2 {
>>> > + test2() : x(y) {}
>>> > +
>>> > + void foo() {
>>> > + if (this == 0) { }
>>> > + // expected-warning at -1{{'this' pointer cannot be null in
>>> well-defined C++ code; comparison may be assumed to always evaluate to
>>> false}}
>>> > + if (this != 0) { }
>>> > + // expected-warning at -1{{'this' pointer cannot be null in
>>> well-defined C++ code; comparison may be assumed to always evaluate to
>>> true}}
>>> > + }
>>> > +
>>> > + void bar() {
>>> > + if (x == 1) { }
>>> > + if (&x == 0) { }
>>> > + // expected-warning at -1{{reference cannot be bound to
>>> dereferenced null pointer in well-defined C++ code; comparison may be
>>> assumed to always evaluate to false}}
>>> > + if (&x != 0) { }
>>> > + // expected-warning at -1{{reference cannot be bound to
>>> dereferenced null pointer in well-defined C++ code; comparison may be
>>> assumed to always evaluate to true}}
>>> > + }
>>> > +
>>> > + int &x;
>>> > + int y;
>>> > +};
>>> >
>>> > Added: cfe/trunk/test/SemaCXX/warn-undefined-bool-conversion.cpp
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/warn-undefined-bool-conversion.cpp?rev=210372&view=auto
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/test/SemaCXX/warn-undefined-bool-conversion.cpp (added)
>>> > +++ cfe/trunk/test/SemaCXX/warn-undefined-bool-conversion.cpp Fri Jun
>>> 6 16:39:26 2014
>>> > @@ -0,0 +1,37 @@
>>> > +// RUN: %clang_cc1 -fsyntax-only -verify %s
>>> > +// RUN: %clang_cc1 -fsyntax-only -verify -Wundefined-bool-conversion
>>> %s
>>> > +// RUN: %clang_cc1 -fsyntax-only -verify -Wno-bool-conversion
>>> -Wundefined-bool-conversion %s
>>> > +// RUN: %clang_cc1 -fsyntax-only -verify -Wbool-conversion %s
>>> > +
>>> > +void test1(int &x) {
>>> > + if (x == 1) { }
>>> > + if (&x) { }
>>> > + // expected-warning at -1{{reference cannot be bound to dereferenced
>>> null pointer in well-defined C++ code; pointer may be assumed always
>>> converted to true}}
>>> > +
>>> > + if (!&x) { }
>>> > + // expected-warning at -1{{reference cannot be bound to dereferenced
>>> null pointer in well-defined C++ code; pointer may be assumed always
>>> converted to true}}
>>> > +}
>>> > +
>>> > +class test2 {
>>> > + test2() : x(y) {}
>>> > +
>>> > + void foo() {
>>> > + if (this) { }
>>> > + // expected-warning at -1{{'this' pointer cannot be null in
>>> well-defined C++ code; pointer may be assumed always converted to true}}
>>> > +
>>> > + if (!this) { }
>>> > + // expected-warning at -1{{'this' pointer cannot be null in
>>> well-defined C++ code; pointer may be assumed always converted to true}}
>>> > + }
>>> > +
>>> > + void bar() {
>>> > + if (x == 1) { }
>>> > + if (&x) { }
>>> > + // expected-warning at -1{{reference cannot be bound to
>>> dereferenced null pointer in well-defined C++ code; pointer may be assumed
>>> always converted to true}}
>>> > +
>>> > + if (!&x) { }
>>> > + // expected-warning at -1{{reference cannot be bound to
>>> dereferenced null pointer in well-defined C++ code; pointer may be assumed
>>> always converted to true}}
>>> > + }
>>> > +
>>> > + int &x;
>>> > + int y;
>>> > +};
>>> >
>>> >
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