r193418 - Add -Wstring-plus-char, which warns when adding char literals to C strings.
Jordan Rose
jordan_rose at apple.com
Fri Oct 25 09:52:00 PDT 2013
Author: jrose
Date: Fri Oct 25 11:52:00 2013
New Revision: 193418
URL: http://llvm.org/viewvc/llvm-project?rev=193418&view=rev
Log:
Add -Wstring-plus-char, which warns when adding char literals to C strings.
Specifically, this warns when a character literal is added (using '+') to a
variable with type 'char *' (or any other pointer to character type). Like
-Wstring-plus-int, there is a fix-it to change "foo + 'a'" to "&foo['a']"
iff the character literal is on the right side of the string.
Patch by Anders Rönnholm!
Added:
cfe/trunk/test/Sema/string-plus-char.c
cfe/trunk/test/SemaCXX/string-plus-char.cpp
Modified:
cfe/trunk/include/clang/Basic/DiagnosticGroups.td
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaExpr.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticGroups.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticGroups.td?rev=193418&r1=193417&r2=193418&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticGroups.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticGroups.td Fri Oct 25 11:52:00 2013
@@ -269,6 +269,7 @@ def GNUStaticFloatInit : DiagGroup<"gnu-
def StaticFloatInit : DiagGroup<"static-float-init", [GNUStaticFloatInit]>;
def GNUStatementExpression : DiagGroup<"gnu-statement-expression">;
def StringPlusInt : DiagGroup<"string-plus-int">;
+def StringPlusChar : DiagGroup<"string-plus-char">;
def StrncatSize : DiagGroup<"strncat-size">;
def TautologicalOutOfRangeCompare : DiagGroup<"tautological-constant-out-of-range-compare">;
def TautologicalCompare : DiagGroup<"tautological-compare",
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=193418&r1=193417&r2=193418&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Fri Oct 25 11:52:00 2013
@@ -4292,7 +4292,10 @@ def warn_self_assignment : Warning<
def warn_string_plus_int : Warning<
"adding %0 to a string does not append to the string">,
InGroup<StringPlusInt>;
-def note_string_plus_int_silence : Note<
+def warn_string_plus_char : Warning<
+ "adding %0 to a string pointer does not append to the string">,
+ InGroup<StringPlusChar>;
+def note_string_plus_scalar_silence : Note<
"use array indexing to silence this warning">;
def warn_sizeof_array_param : Warning<
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=193418&r1=193417&r2=193418&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Fri Oct 25 11:52:00 2013
@@ -6963,12 +6963,63 @@ static void diagnoseStringPlusInt(Sema &
// Only print a fixit for "str" + int, not for int + "str".
if (IndexExpr == RHSExpr) {
SourceLocation EndLoc = Self.PP.getLocForEndOfToken(RHSExpr->getLocEnd());
- Self.Diag(OpLoc, diag::note_string_plus_int_silence)
+ Self.Diag(OpLoc, diag::note_string_plus_scalar_silence)
<< FixItHint::CreateInsertion(LHSExpr->getLocStart(), "&")
<< FixItHint::CreateReplacement(SourceRange(OpLoc), "[")
<< FixItHint::CreateInsertion(EndLoc, "]");
} else
- Self.Diag(OpLoc, diag::note_string_plus_int_silence);
+ Self.Diag(OpLoc, diag::note_string_plus_scalar_silence);
+}
+
+/// \brief Emit a warning when adding a char literal to a string.
+static void diagnoseStringPlusChar(Sema &Self, SourceLocation OpLoc,
+ Expr *LHSExpr, Expr *RHSExpr) {
+ const DeclRefExpr *StringRefExpr =
+ dyn_cast<DeclRefExpr>(LHSExpr->IgnoreImpCasts());
+ const CharacterLiteral *CharExpr =
+ dyn_cast<CharacterLiteral>(RHSExpr->IgnoreImpCasts());
+ if (!StringRefExpr) {
+ StringRefExpr = dyn_cast<DeclRefExpr>(RHSExpr->IgnoreImpCasts());
+ CharExpr = dyn_cast<CharacterLiteral>(LHSExpr->IgnoreImpCasts());
+ }
+
+ if (!CharExpr || !StringRefExpr)
+ return;
+
+ const QualType StringType = StringRefExpr->getType();
+
+ // Return if not a PointerType.
+ if (!StringType->isAnyPointerType())
+ return;
+
+ // Return if not a CharacterType.
+ if (!StringType->getPointeeType()->isAnyCharacterType())
+ return;
+
+ ASTContext &Ctx = Self.getASTContext();
+ SourceRange DiagRange(LHSExpr->getLocStart(), RHSExpr->getLocEnd());
+
+ const QualType CharType = CharExpr->getType();
+ if (!CharType->isAnyCharacterType() &&
+ CharType->isIntegerType() &&
+ llvm::isUIntN(Ctx.getCharWidth(), CharExpr->getValue())) {
+ Self.Diag(OpLoc, diag::warn_string_plus_char)
+ << DiagRange << Ctx.CharTy;
+ } else {
+ Self.Diag(OpLoc, diag::warn_string_plus_char)
+ << DiagRange << CharExpr->getType();
+ }
+
+ // Only print a fixit for str + char, not for char + str.
+ if (isa<CharacterLiteral>(RHSExpr->IgnoreImpCasts())) {
+ SourceLocation EndLoc = Self.PP.getLocForEndOfToken(RHSExpr->getLocEnd());
+ Self.Diag(OpLoc, diag::note_string_plus_scalar_silence)
+ << FixItHint::CreateInsertion(LHSExpr->getLocStart(), "&")
+ << FixItHint::CreateReplacement(SourceRange(OpLoc), "[")
+ << FixItHint::CreateInsertion(EndLoc, "]");
+ } else {
+ Self.Diag(OpLoc, diag::note_string_plus_scalar_silence);
+ }
}
/// \brief Emit error when two pointers are incompatible.
@@ -6997,9 +7048,11 @@ QualType Sema::CheckAdditionOperands( //
if (LHS.isInvalid() || RHS.isInvalid())
return QualType();
- // Diagnose "string literal" '+' int.
- if (Opc == BO_Add)
+ // Diagnose "string literal" '+' int and string '+' "char literal".
+ if (Opc == BO_Add) {
diagnoseStringPlusInt(*this, Loc, LHS.get(), RHS.get());
+ diagnoseStringPlusChar(*this, Loc, LHS.get(), RHS.get());
+ }
// handle the common case first (both operands are arithmetic).
if (!compType.isNull() && compType->isArithmeticType()) {
Added: cfe/trunk/test/Sema/string-plus-char.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/string-plus-char.c?rev=193418&view=auto
==============================================================================
--- cfe/trunk/test/Sema/string-plus-char.c (added)
+++ cfe/trunk/test/Sema/string-plus-char.c Fri Oct 25 11:52:00 2013
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+void f(const char *s) {
+ char *str = 0;
+ char *str2 = str + 'c'; // expected-warning {{adding 'char' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+
+ const char *constStr = s + 'c'; // expected-warning {{adding 'char' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+
+ str = 'c' + str;// expected-warning {{adding 'char' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+
+ // no-warning
+ char c = 'c';
+ str = str + c;
+ str = c + str;
+}
Added: cfe/trunk/test/SemaCXX/string-plus-char.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/string-plus-char.cpp?rev=193418&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/string-plus-char.cpp (added)
+++ cfe/trunk/test/SemaCXX/string-plus-char.cpp Fri Oct 25 11:52:00 2013
@@ -0,0 +1,32 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 -verify %s
+
+class A {
+public:
+ A(): str() { }
+ A(const char *p) { }
+ A(char *p) : str(p + 'a') { } // expected-warning {{adding 'char' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+ A& operator+(const char *p) { return *this; }
+ A& operator+(char ch) { return *this; }
+ char * str;
+};
+
+void f(const char *s) {
+ A a = s + 'a'; // // expected-warning {{adding 'char' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+ a = a + s + 'b'; // no-warning
+
+ char *str = 0;
+ char *str2 = str + 'c'; // expected-warning {{adding 'char' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+
+ const char *constStr = s + 'c'; // expected-warning {{adding 'char' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+
+ str = 'c' + str;// expected-warning {{adding 'char' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+
+ wchar_t *wstr;
+ wstr = wstr + L'c'; // expected-warning {{adding 'wchar_t' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+ str2 = str + u'a'; // expected-warning {{adding 'char16_t' to a string pointer does not append to the string}} expected-note {{use array indexing to silence this warning}}
+
+ // no-warning
+ char c = 'c';
+ str = str + c;
+ str = c + str;
+}
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