From 84ea41fd17d09e75c50531d8cb4b52d2cc0acbbb Mon Sep 17 00:00:00 2001 From: David Bolvansky Date: Mon, 23 Sep 2019 14:21:08 +0000 Subject: [PATCH] [Diagnostics] Warn if '<<' in bool context with -Wint-in-bool-context (GCC compatibility) Extracted from D63082, addressed review comments related to a warning message. llvm-svn: 372612 --- clang/include/clang/Basic/DiagnosticGroups.td | 2 ++ clang/include/clang/Basic/DiagnosticSemaKinds.td | 3 +++ clang/lib/Sema/SemaChecking.cpp | 11 ++++++++- clang/test/Sema/warn-int-in-bool-context.c | 31 ++++++++++++++++++++++++ clang/test/SemaCXX/cxx2a-explicit-bool.cpp | 2 +- 5 files changed, 47 insertions(+), 2 deletions(-) create mode 100644 clang/test/Sema/warn-int-in-bool-context.c diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td index 4e2f85d..4c7ea3d 100644 --- a/clang/include/clang/Basic/DiagnosticGroups.td +++ b/clang/include/clang/Basic/DiagnosticGroups.td @@ -499,6 +499,7 @@ def StringCompare : DiagGroup<"string-compare">; def StringPlusInt : DiagGroup<"string-plus-int">; def StringPlusChar : DiagGroup<"string-plus-char">; def StrncatSize : DiagGroup<"strncat-size">; +def IntInBoolContext : DiagGroup<"int-in-bool-context">; def TautologicalTypeLimitCompare : DiagGroup<"tautological-type-limit-compare">; def TautologicalUnsignedZeroCompare : DiagGroup<"tautological-unsigned-zero-compare">; def TautologicalUnsignedEnumZeroCompare : DiagGroup<"tautological-unsigned-enum-zero-compare">; @@ -821,6 +822,7 @@ def Most : DiagGroup<"most", [ Format, Implicit, InfiniteRecursion, + IntInBoolContext, MismatchedTags, MissingBraces, Move, diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 5f47da0..26b328b 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -5720,6 +5720,9 @@ def warn_precedence_conditional : Warning< def note_precedence_conditional_first : Note< "place parentheses around the '?:' expression to evaluate it first">; +def warn_left_shift_in_bool_context : Warning< + "converting the result of '<<' to a boolean; did you mean '(%0) != 0'?">, + InGroup; def warn_logical_instead_of_bitwise : Warning< "use of logical '%0' with constant operand">, InGroup>; diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp index 7aeace5..cbe7e9a 100644 --- a/clang/lib/Sema/SemaChecking.cpp +++ b/clang/lib/Sema/SemaChecking.cpp @@ -11256,10 +11256,16 @@ static bool isSameWidthConstantConversion(Sema &S, Expr *E, QualType T, return true; } -static void DiagnoseIntInBoolContext(Sema &S, const Expr *E) { +static void DiagnoseIntInBoolContext(Sema &S, Expr *E) { E = E->IgnoreParenImpCasts(); SourceLocation ExprLoc = E->getExprLoc(); + if (const auto *BO = dyn_cast(E)) { + BinaryOperator::Opcode Opc = BO->getOpcode(); + if (Opc == BO_Shl) + S.Diag(ExprLoc, diag::warn_left_shift_in_bool_context) << E; + } + if (const auto *CO = dyn_cast(E)) { const auto *LHS = dyn_cast(CO->getTrueExpr()); if (!LHS) { @@ -11585,6 +11591,9 @@ static void CheckImplicitConversion(Sema &S, Expr *E, QualType T, S.DiscardMisalignedMemberAddress(Target, E); + if (Target->isBooleanType()) + DiagnoseIntInBoolContext(S, E); + if (!Source->isIntegerType() || !Target->isIntegerType()) return; diff --git a/clang/test/Sema/warn-int-in-bool-context.c b/clang/test/Sema/warn-int-in-bool-context.c new file mode 100644 index 0000000..0a0d88f --- /dev/null +++ b/clang/test/Sema/warn-int-in-bool-context.c @@ -0,0 +1,31 @@ +// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wint-in-bool-context %s +// RUN: %clang_cc1 -x c -fsyntax-only -verify -Wall %s +// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wint-in-bool-context %s +// RUN: %clang_cc1 -x c++ -fsyntax-only -verify -Wall %s + +#define ONE 1 +#define TWO 2 + +#define SHIFT(l, r) l << r + +#ifdef __cplusplus +typedef bool boolean; +#else +typedef _Bool boolean; +#endif + +int test(int a) { + boolean r; + r = (1 << 3); // expected-warning {{converting the result of '<<' to a boolean; did you mean '(1 << 3) != 0'?}} + r = TWO << 7; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(2 << 7) != 0'?}} + r = a << 7; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(a << 7) != 0'?}} + r = ONE << a; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(1 << a) != 0'?}} + if (TWO << 4) // expected-warning {{converting the result of '<<' to a boolean; did you mean '(2 << 4) != 0'?}} + return a; + + if (a << TWO) // expected-warning {{converting the result of '<<' to a boolean; did you mean '(a << 2) != 0'?}} + return a; + + // Don't warn in macros. + return SHIFT(1, a); +} diff --git a/clang/test/SemaCXX/cxx2a-explicit-bool.cpp b/clang/test/SemaCXX/cxx2a-explicit-bool.cpp index 56fa76f..bb62a25 100644 --- a/clang/test/SemaCXX/cxx2a-explicit-bool.cpp +++ b/clang/test/SemaCXX/cxx2a-explicit-bool.cpp @@ -20,7 +20,7 @@ namespace special_cases template struct A { // expected-note@-1+ {{candidate constructor}} - explicit(1 << a) + explicit(1 << a) // expected-warning {{converting the result of '<<' to a boolean; did you mean '(1 << -1) != 0'?}} // expected-note@-1 {{negative shift count -1}} // expected-error@-2 {{explicit specifier argument is not a constant expression}} A(int); -- 2.7.4