gchatelet created this revision.
gchatelet added a reviewer: courbet.
Herald added subscribers: shchenz, kbarton, xazax.hun, nemanjai.
gchatelet requested review of this revision.
Herald added a project: clang-tools-extra.
Herald added a subscriber: cfe-commits.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D104018
Files:
clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines-narrowing-conversions.rst
clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-narrowing-conversions-narrowinginteger-option.cpp
Index: clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-narrowing-conversions-narrowinginteger-option.cpp
===================================================================
--- /dev/null
+++ clang-tools-extra/test/clang-tidy/checkers/cppcoreguidelines-narrowing-conversions-narrowinginteger-option.cpp
@@ -0,0 +1,23 @@
+// RUN: %check_clang_tidy -check-suffix=DEFAULT %s \
+// RUN: cppcoreguidelines-narrowing-conversions %t -- \
+// RUN: -config='{CheckOptions: [{key: cppcoreguidelines-narrowing-conversions.WarnOnIntegerNarrowingConversion, value: true}]}'
+
+// RUN: %check_clang_tidy -check-suffix=DISABLED %s \
+// RUN: cppcoreguidelines-narrowing-conversions %t -- \
+// RUN: -config='{CheckOptions: [{key: cppcoreguidelines-narrowing-conversions.WarnOnIntegerNarrowingConversion, value: false}]}'
+
+void foo(unsigned long long value) {
+ int a = value;
+ // CHECK-MESSAGES-DEFAULT: :[[@LINE-1]]:11: warning: narrowing conversion from 'unsigned long long' to signed type 'int' is implementation-defined [cppcoreguidelines-narrowing-conversions]
+ // DISABLED: No warning for integer narrowing conversions when WarnOnIntegerNarrowingConversion = false.
+ long long b = value;
+ // CHECK-MESSAGES-DEFAULT: :[[@LINE-1]]:17: warning: narrowing conversion from 'unsigned long long' to signed type 'long long' is implementation-defined [cppcoreguidelines-narrowing-conversions]
+ // DISABLED: No warning for integer narrowing conversions when WarnOnIntegerNarrowingConversion = false.
+}
+
+void casting_float_to_bool_is_still_operational_when_integer_narrowing_is_disabled(float f) {
+ if (f) {
+ // CHECK-MESSAGES-DEFAULT: :[[@LINE-1]]:7: warning: narrowing conversion from 'float' to 'bool' [cppcoreguidelines-narrowing-conversions]
+ // CHECK-MESSAGES-DISABLED: :[[@LINE-2]]:7: warning: narrowing conversion from 'float' to 'bool' [cppcoreguidelines-narrowing-conversions]
+ }
+}
Index: clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines-narrowing-conversions.rst
===================================================================
--- clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines-narrowing-conversions.rst
+++ clang-tools-extra/docs/clang-tidy/checks/cppcoreguidelines-narrowing-conversions.rst
@@ -13,7 +13,8 @@
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#es46-avoid-lossy-narrowing-truncating-arithmetic-conversions.
We enforce only part of the guideline, more specifically, we flag narrowing conversions from:
- - an integer to a narrower integer (e.g. ``char`` to ``unsigned char``),
+ - an integer to a narrower integer (e.g. ``char`` to ``unsigned char``)
+ if WarnOnIntegerNarrowingConversion Option is set,
- an integer to a narrower floating-point (e.g. ``uint64_t`` to ``float``),
- a floating-point to an integer (e.g. ``double`` to ``int``),
- a floating-point to a narrower floating-point (e.g. ``double`` to ``float``)
@@ -30,6 +31,11 @@
Options
-------
+.. option:: WarnOnIntegerNarrowingConversion
+
+ When `true`, the check will warn on narrowing integer conversion
+ (e.g. ``int`` to ``size_t``). `true` by default.
+
.. option:: WarnOnFloatingPointNarrowingConversion
When `true`, the check will warn on narrowing floating point conversion
Index: clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
===================================================================
--- clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
+++ clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.h
@@ -93,6 +93,7 @@
void handleBinaryOperator(const ASTContext &Context,
const BinaryOperator &Op);
+ const bool WarnOnIntegerNarrowingConversion;
const bool WarnOnFloatingPointNarrowingConversion;
const bool WarnWithinTemplateInstantiation;
const bool WarnOnEquivalentBitWidth;
Index: clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
+++ clang-tools-extra/clang-tidy/cppcoreguidelines/NarrowingConversionsCheck.cpp
@@ -35,6 +35,8 @@
NarrowingConversionsCheck::NarrowingConversionsCheck(StringRef Name,
ClangTidyContext *Context)
: ClangTidyCheck(Name, Context),
+ WarnOnIntegerNarrowingConversion(
+ Options.get("WarnOnIntegerNarrowingConversion", true)),
WarnOnFloatingPointNarrowingConversion(
Options.get("WarnOnFloatingPointNarrowingConversion", true)),
WarnWithinTemplateInstantiation(
@@ -45,6 +47,8 @@
void NarrowingConversionsCheck::storeOptions(
ClangTidyOptions::OptionMap &Opts) {
+ Options.store(Opts, "WarnOnIntegerNarrowingConversion",
+ WarnOnIntegerNarrowingConversion);
Options.store(Opts, "WarnOnFloatingPointNarrowingConversion",
WarnOnFloatingPointNarrowingConversion);
Options.store(Opts, "WarnWithinTemplateInstantiation",
@@ -294,34 +298,37 @@
SourceLocation SourceLoc,
const Expr &Lhs,
const Expr &Rhs) {
- const BuiltinType *ToType = getBuiltinType(Lhs);
- // From [conv.integral]p7.3.8:
- // Conversions to unsigned integer is well defined so no warning is issued.
- // "The resulting value is the smallest unsigned value equal to the source
- // value modulo 2^n where n is the number of bits used to represent the
- // destination type."
- if (ToType->isUnsignedInteger())
- return;
- const BuiltinType *FromType = getBuiltinType(Rhs);
-
- // With this option, we don't warn on conversions that have equivalent width
- // in bits. eg. uint32 <-> int32.
- if (!WarnOnEquivalentBitWidth) {
- uint64_t FromTypeSize = Context.getTypeSize(FromType);
- uint64_t ToTypeSize = Context.getTypeSize(ToType);
- if (FromTypeSize == ToTypeSize)
+ if (WarnOnIntegerNarrowingConversion) {
+ const BuiltinType *ToType = getBuiltinType(Lhs);
+ // From [conv.integral]p7.3.8:
+ // Conversions to unsigned integer is well defined so no warning is issued.
+ // "The resulting value is the smallest unsigned value equal to the source
+ // value modulo 2^n where n is the number of bits used to represent the
+ // destination type."
+ if (ToType->isUnsignedInteger())
return;
- }
+ const BuiltinType *FromType = getBuiltinType(Rhs);
- llvm::APSInt IntegerConstant;
- if (getIntegerConstantExprValue(Context, Rhs, IntegerConstant)) {
- if (!isWideEnoughToHold(Context, IntegerConstant, *ToType))
- diagNarrowIntegerConstantToSignedInt(SourceLoc, Lhs, Rhs, IntegerConstant,
- Context.getTypeSize(FromType));
- return;
+ // With this option, we don't warn on conversions that have equivalent width
+ // in bits. eg. uint32 <-> int32.
+ if (!WarnOnEquivalentBitWidth) {
+ uint64_t FromTypeSize = Context.getTypeSize(FromType);
+ uint64_t ToTypeSize = Context.getTypeSize(ToType);
+ if (FromTypeSize == ToTypeSize)
+ return;
+ }
+
+ llvm::APSInt IntegerConstant;
+ if (getIntegerConstantExprValue(Context, Rhs, IntegerConstant)) {
+ if (!isWideEnoughToHold(Context, IntegerConstant, *ToType))
+ diagNarrowIntegerConstantToSignedInt(SourceLoc, Lhs, Rhs,
+ IntegerConstant,
+ Context.getTypeSize(FromType));
+ return;
+ }
+ if (!isWideEnoughToHold(Context, *FromType, *ToType))
+ diagNarrowTypeToSignedInt(SourceLoc, Lhs, Rhs);
}
- if (!isWideEnoughToHold(Context, *FromType, *ToType))
- diagNarrowTypeToSignedInt(SourceLoc, Lhs, Rhs);
}
void NarrowingConversionsCheck::handleIntegralToBoolean(
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