Skip to content

[C] Allow __attribute__((nonstring)) on multidimensional arrays #138133

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 3 commits into from
May 2, 2025
Merged

[C] Allow __attribute__((nonstring)) on multidimensional arrays #138133

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
3ee89ca
[C] Allow __attribute__((nonstring)) on multidimensional arrays
AaronBallman May 1, 2025
94ff2f6
Go with a more direct implementation; NFC
AaronBallman May 1, 2025
f4a56c1
Update tests
AaronBallman May 1, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 15 additions & 2 deletions clang/lib/Sema/SemaInit.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -261,8 +261,21 @@ static void CheckStringInit(Expr *Str, QualType &DeclT, const ArrayType *AT,
<< Str->getSourceRange();
else if (StrLength - 1 == ArrayLen) {
// If the entity being initialized has the nonstring attribute, then
// silence the "missing nonstring" diagnostic.
if (const ValueDecl *D = Entity.getDecl();
// silence the "missing nonstring" diagnostic. If there's no entity,
// check whether we're initializing an array of arrays; if so, walk the
// parents to find an entity.
auto FindCorrectEntity = [](const InitializedEntity &Entity) {
const ValueDecl *Ret = nullptr;
for (const InitializedEntity *E = &Entity; E; E = Entity.getParent()) {
Ret = E->getDecl();
if (Ret)
break;
if (!E->getType()->isArrayType())
break;
}
return Ret;
};
if (const ValueDecl *D = FindCorrectEntity(Entity);
!D || !D->hasAttr<NonStringAttr>())
S.Diag(
Str->getBeginLoc(),
Expand Down
80 changes: 79 additions & 1 deletion clang/test/Sema/attr-nonstring.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
// RUN: %clang_cc1 -fsyntax-only -verify=noncxx,expected,no-nonstring -Wextra %s
// RUN: %clang_cc1 -fsyntax-only -verify=noncxx,expected,compat -Wc++-unterminated-string-initialization %s
// RUN: %clang_cc1 -fsyntax-only -verify=noncxx,expected,compat -Wc++-compat %s
// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx -x c++ %s
// RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx -x c++ -Wno-c99-designator %s
// RUN: %clang_cc1 -fsyntax-only -verify=expected,noncxx -Wno-unterminated-string-initialization %s
// RUN: %clang_cc1 -fsyntax-only -verify=expected,noncxx -Wc++-compat -Wextra -Wno-unterminated-string-initialization -Wno-c++-unterminated-string-initialization %s

Expand Down Expand Up @@ -39,3 +39,81 @@ __attribute__((nonstring)) int eek2; // expected-warning {{'nonstri
// diagnostic when you overwrite more than just the null terminator.
char too_big[3] = "this is too big"; // noncxx-warning {{initializer-string for char array is too long}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 16 (including the null terminating character)}}

// Show that this also applies to arrays of objects containing strings, too.
const char md_array[][3] __attribute__((nonstring)) = { "BAR", "FOO", }; // compat-warning 2 {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error 2 {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}

struct StructWithNSArray {
__attribute__((nonstring)) char blech[3];
};

struct StructWithNSArray s1[] = {
{ "FOO" }, // compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
{ "BAR" } // compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
};

struct T1 {
struct StructWithNSArray s[2];
};
struct U1 {
struct T1 t[2];
};
struct U1 u[] = {
{
.t[0] = {
.s[0] = { "FOO" }, // compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
.s[1] = { "BAR" } // compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
},
.t[1] = {
.s[0] = { "BIP" }, // compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
.s[1] = { "BOP" } // compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
}
}
};

struct StructWithoutNSArray {
char blech[3];
};

struct StructWithoutNSArray s2[] = {
{ "FOO" }, // no-nonstring-warning {{initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute?}} \
compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
{ "BAR" } // no-nonstring-warning {{initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute?}} \
compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
};

struct T2 {
struct StructWithoutNSArray s[2];
};
struct U2 {
struct T2 t[2];
};
struct U2 u2[] = {
{
.t[0] = {
.s[0] = { "FOO" }, // no-nonstring-warning {{initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute?}} \
compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
.s[1] = { "BAR" } // no-nonstring-warning {{initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute?}} \
compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
},
.t[1] = {
.s[0] = { "BIP" }, // no-nonstring-warning {{initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute?}} \
compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
.s[1] = { "BOP" } // no-nonstring-warning {{initializer-string for character array is too long, array size is 3 but initializer has size 4 (including the null terminating character); did you mean to use the 'nonstring' attribute?}} \
compat-warning {{initializer-string for character array is too long for C++, array size is 3 but initializer has size 4 (including the null terminating character)}} \
cxx-error {{initializer-string for char array is too long, array size is 3 but initializer has size 4 (including the null terminating character)}}
}
}
};