https://github.com/DeanSturtevant1 updated
https://github.com/llvm/llvm-project/pull/150962
>From 1c6029240e6a19981105fc7561453fc2857e4703 Mon Sep 17 00:00:00 2001
From: Dean Sturtevant <dsturtev...@google.com>
Date: Mon, 28 Jul 2025 10:30:50 -0400
Subject: [PATCH 1/3] Fix Clang bug that -Wformat-signedness is not reported
properly.
The goal is to correctly identify diagnostics that are emitted by virtue of
-Wformat-signedness.
Before this change, diagnostic messages triggered by -Wformat-signedness might
look like:
format specifies type 'unsigned int' but the argument has type 'int' [-Wformat]
signedness of format specifier 'u' is incompatible with 'c' [-Wformat]
With this change:
format specifies type 'unsigned int' but the argument has type 'int', which
differs in signedness [-Wformat-signedness]
signedness of format specifier 'u' is incompatible with 'c'
[-Wformat-signedness]
Fix:
- handleFormatSignedness can now return NoMatchSignedness. Callers handle this.
- warn_format_conversion_argument_type extends the message it used to emit by a
string that
mentions "signedness".
- warn_format_cmp_specifier_sign_mismatch is now correctly categorized as a
diagnostic controlled by -Wformat-signedness.
---
.../clang/Basic/DiagnosticSemaKinds.td | 4 +-
clang/lib/Sema/SemaChecking.cpp | 41 +++++++------
clang/test/Sema/format-strings-signedness.c | 60 +++++++++----------
3 files changed, 56 insertions(+), 49 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index da4216dbda4c9..dfca6577c7701 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10400,6 +10400,7 @@ def
warn_format_conversion_argument_type_mismatch_pedantic : Extension<
InGroup<FormatPedantic>;
def warn_format_conversion_argument_type_mismatch_signedness : Warning<
warn_format_conversion_argument_type_mismatch.Summary>,
+ "format specifies type %0 but the argument has %select{type|underlying
type}2 %1, which differs in signedness">,
InGroup<FormatSignedness>, DefaultIgnore;
def warn_format_conversion_argument_type_mismatch_confusion : Warning<
warn_format_conversion_argument_type_mismatch.Summary>,
@@ -10513,7 +10514,8 @@ def warn_format_cmp_sensitivity_mismatch : Warning<
def warn_format_cmp_specifier_mismatch : Warning<
"format specifier '%0' is incompatible with '%1'">, InGroup<Format>;
def warn_format_cmp_specifier_sign_mismatch : Warning<
- "signedness of format specifier '%0' is incompatible with '%1'">,
InGroup<Format>;
+ "signedness of format specifier '%0' is incompatible with '%1'">,
InGroup<FormatSignedness>,
+ DefaultIgnore;
def warn_format_cmp_specifier_mismatch_pedantic : Extension<
warn_format_cmp_specifier_sign_mismatch.Summary>, InGroup<FormatPedantic>;
def note_format_cmp_with : Note<
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index c74b67106ad74..bd8a8f6264d16 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -40,6 +40,7 @@
#include "clang/AST/UnresolvedSet.h"
#include "clang/Basic/AddressSpaces.h"
#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticSema.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
@@ -7645,17 +7646,13 @@ bool EquatableFormatArgument::VerifyCompatible(
break;
case MK::NoMatchSignedness:
- if (!S.getDiagnostics().isIgnored(
- diag::warn_format_conversion_argument_type_mismatch_signedness,
- ElementLoc)) {
- EmitDiagnostic(S,
- S.PDiag(diag::warn_format_cmp_specifier_sign_mismatch)
- << buildFormatSpecifier()
- << Other.buildFormatSpecifier(),
- FmtExpr, InFunctionCall);
- HadError = S.Diag(Other.ElementLoc, diag::note_format_cmp_with)
- << 0 << Other.Range;
- }
+ EmitDiagnostic(S,
+ S.PDiag(diag::warn_format_cmp_specifier_sign_mismatch)
+ << buildFormatSpecifier()
+ << Other.buildFormatSpecifier(),
+ FmtExpr, InFunctionCall);
+ HadError = S.Diag(Other.ElementLoc, diag::note_format_cmp_with)
+ << 0 << Other.Range;
break;
}
return !HadError;
@@ -8189,11 +8186,14 @@ static analyze_format_string::ArgType::MatchKind
handleFormatSignedness(analyze_format_string::ArgType::MatchKind Match,
DiagnosticsEngine &Diags, SourceLocation Loc) {
if (Match == analyze_format_string::ArgType::NoMatchSignedness) {
- Match =
+ if (Diags.isIgnored(
+ diag::warn_format_conversion_argument_type_mismatch_signedness,
+ Loc) ||
Diags.isIgnored(
- diag::warn_format_conversion_argument_type_mismatch_signedness,
Loc)
- ? analyze_format_string::ArgType::Match
- : analyze_format_string::ArgType::NoMatch;
+ // Arbitrary -Wformat diagnostic to detect -Wno-format:
+ diag::warn_format_conversion_argument_type_mismatch, Loc)) {
+ return analyze_format_string::ArgType::Match;
+ }
}
return Match;
}
@@ -8407,8 +8407,10 @@ CheckPrintfHandler::checkFormatExpr(const
analyze_printf::PrintfSpecifier &FS,
case ArgType::Match:
case ArgType::MatchPromotion:
case ArgType::NoMatchPromotionTypeConfusion:
- case ArgType::NoMatchSignedness:
llvm_unreachable("expected non-matching");
+ case ArgType::NoMatchSignedness:
+ Diag = diag::warn_format_conversion_argument_type_mismatch_signedness;
+ break;
case ArgType::NoMatchPedantic:
Diag = diag::warn_format_conversion_argument_type_mismatch_pedantic;
break;
@@ -8733,9 +8735,10 @@ bool CheckScanfHandler::HandleScanfSpecifier(
analyze_format_string::ArgType::MatchKind Match =
AT.matchesType(S.Context, Ex->getType());
Match = handleFormatSignedness(Match, S.getDiagnostics(), Ex->getExprLoc());
- bool Pedantic = Match == analyze_format_string::ArgType::NoMatchPedantic;
if (Match == analyze_format_string::ArgType::Match)
return true;
+ bool Pedantic = Match == analyze_format_string::ArgType::NoMatchPedantic;
+ bool Signedness = Match == analyze_format_string::ArgType::NoMatchSignedness;
ScanfSpecifier fixedFS = FS;
bool Success = fixedFS.fixType(Ex->getType(),
Ex->IgnoreImpCasts()->getType(),
@@ -8743,7 +8746,9 @@ bool CheckScanfHandler::HandleScanfSpecifier(
unsigned Diag =
Pedantic ? diag::warn_format_conversion_argument_type_mismatch_pedantic
- : diag::warn_format_conversion_argument_type_mismatch;
+ : Signedness
+ ? diag::warn_format_conversion_argument_type_mismatch_signedness
+ : diag::warn_format_conversion_argument_type_mismatch;
if (Success) {
// Get the fix string from the fixed format specifier.
diff --git a/clang/test/Sema/format-strings-signedness.c
b/clang/test/Sema/format-strings-signedness.c
index d5a8140d9ef8a..773ff412ac177 100644
--- a/clang/test/Sema/format-strings-signedness.c
+++ b/clang/test/Sema/format-strings-signedness.c
@@ -39,13 +39,13 @@ void test_printf_unsigned_char(unsigned char x)
void test_printf_int(int x)
{
printf("%d", x); // no-warning
- printf("%u", x); // expected-warning{{format specifies type 'unsigned int'
but the argument has type 'int'}}
- printf("%x", x); // expected-warning{{format specifies type 'unsigned int'
but the argument has type 'int'}}
+ printf("%u", x); // expected-warning{{format specifies type 'unsigned int'
but the argument has type 'int', which differs in signedness}}
+ printf("%x", x); // expected-warning{{format specifies type 'unsigned int'
but the argument has type 'int', which differs in signedness}}
}
void test_printf_unsigned(unsigned x)
{
- printf("%d", x); // expected-warning{{format specifies type 'int' but the
argument has type 'unsigned int'}}
+ printf("%d", x); // expected-warning{{format specifies type 'int' but the
argument has type 'unsigned int', which differs in signedness}}
printf("%u", x); // no-warning
printf("%x", x); // no-warning
}
@@ -53,13 +53,13 @@ void test_printf_unsigned(unsigned x)
void test_printf_long(long x)
{
printf("%ld", x); // no-warning
- printf("%lu", x); // expected-warning{{format specifies type 'unsigned
long' but the argument has type 'long'}}
- printf("%lx", x); // expected-warning{{format specifies type 'unsigned
long' but the argument has type 'long'}}
+ printf("%lu", x); // expected-warning{{format specifies type 'unsigned
long' but the argument has type 'long', which differs in signedness}}
+ printf("%lx", x); // expected-warning{{format specifies type 'unsigned
long' but the argument has type 'long', which differs in signedness}}
}
void test_printf_unsigned_long(unsigned long x)
{
- printf("%ld", x); // expected-warning{{format specifies type 'long' but
the argument has type 'unsigned long'}}
+ printf("%ld", x); // expected-warning{{format specifies type 'long' but
the argument has type 'unsigned long', which differs in signedness}}
printf("%lu", x); // no-warning
printf("%lx", x); // no-warning
}
@@ -67,13 +67,13 @@ void test_printf_unsigned_long(unsigned long x)
void test_printf_long_long(long long x)
{
printf("%lld", x); // no-warning
- printf("%llu", x); // expected-warning{{format specifies type 'unsigned
long long' but the argument has type 'long long'}}
- printf("%llx", x); // expected-warning{{format specifies type 'unsigned
long long' but the argument has type 'long long'}}
+ printf("%llu", x); // expected-warning{{format specifies type 'unsigned
long long' but the argument has type 'long long', which differs in signedness}}
+ printf("%llx", x); // expected-warning{{format specifies type 'unsigned
long long' but the argument has type 'long long', which differs in signedness}}
}
void test_printf_unsigned_long_long(unsigned long long x)
{
- printf("%lld", x); // expected-warning{{format specifies type 'long long'
but the argument has type 'unsigned long long'}}
+ printf("%lld", x); // expected-warning{{format specifies type 'long long'
but the argument has type 'unsigned long long', which differs in signedness}}
printf("%llu", x); // no-warning
printf("%llx", x); // no-warning
}
@@ -85,8 +85,8 @@ enum enum_int {
void test_printf_enum_int(enum enum_int x)
{
printf("%d", x); // no-warning
- printf("%u", x); // expected-warning{{format specifies type 'unsigned int'
but the argument has underlying type 'int'}}
- printf("%x", x); // expected-warning{{format specifies type 'unsigned int'
but the argument has underlying type 'int'}}
+ printf("%u", x); // expected-warning{{format specifies type 'unsigned int'
but the argument has underlying type 'int', which differs in signedness}}
+ printf("%x", x); // expected-warning{{format specifies type 'unsigned int'
but the argument has underlying type 'int', which differs in signedness}}
}
#ifndef _WIN32 // Disabled due to enums have different underlying type on
_WIN32
@@ -96,7 +96,7 @@ enum enum_unsigned {
void test_printf_enum_unsigned(enum enum_unsigned x)
{
- printf("%d", x); // expected-warning{{format specifies type 'int' but the
argument has underlying type 'unsigned int'}}
+ printf("%d", x); // expected-warning{{format specifies type 'int' but the
argument has underlying type 'unsigned int', which differs in signedness}}
printf("%u", x); // no-warning
printf("%x", x); // no-warning
}
@@ -110,8 +110,8 @@ enum enum_long {
void test_printf_enum_long(enum enum_long x)
{
printf("%ld", x); // no-warning
- printf("%lu", x); // expected-warning{{format specifies type 'unsigned
long' but the argument has underlying type 'long'}}
- printf("%lx", x); // expected-warning{{format specifies type 'unsigned
long' but the argument has underlying type 'long'}}
+ printf("%lu", x); // expected-warning{{format specifies type 'unsigned
long' but the argument has underlying type 'long', which differs in signedness}}
+ printf("%lx", x); // expected-warning{{format specifies type 'unsigned
long' but the argument has underlying type 'long', which differs in signedness}}
}
enum enum_unsigned_long {
@@ -120,7 +120,7 @@ enum enum_unsigned_long {
void test_printf_enum_unsigned_long(enum enum_unsigned_long x)
{
- printf("%ld", x); // expected-warning{{format specifies type 'long' but
the argument has underlying type 'unsigned long'}}
+ printf("%ld", x); // expected-warning{{format specifies type 'long' but
the argument has underlying type 'unsigned long', which differs in signedness}}
printf("%lu", x); // no-warning
printf("%lx", x); // no-warning
}
@@ -136,61 +136,61 @@ void test_scanf_unsigned_char(unsigned char *y) {
void test_scanf_int(int *x) {
scanf("%d", x); // no-warning
- scanf("%u", x); // expected-warning{{format specifies type 'unsigned int *'
but the argument has type 'int *'}}
- scanf("%x", x); // expected-warning{{format specifies type 'unsigned int *'
but the argument has type 'int *'}}
+ scanf("%u", x); // expected-warning{{format specifies type 'unsigned int *'
but the argument has type 'int *', which differs in signedness}}
+ scanf("%x", x); // expected-warning{{format specifies type 'unsigned int *'
but the argument has type 'int *', which differs in signedness}}
}
void test_scanf_unsigned(unsigned *x) {
- scanf("%d", x); // expected-warning{{format specifies type 'int *' but the
argument has type 'unsigned int *'}}
+ scanf("%d", x); // expected-warning{{format specifies type 'int *' but the
argument has type 'unsigned int *', which differs in signedness}}
scanf("%u", x); // no-warning
scanf("%x", x); // no-warning
}
void test_scanf_long(long *x) {
scanf("%ld", x); // no-warning
- scanf("%lu", x); // expected-warning{{format specifies type 'unsigned long
*' but the argument has type 'long *'}}
- scanf("%lx", x); // expected-warning{{format specifies type 'unsigned long
*' but the argument has type 'long *'}}
+ scanf("%lu", x); // expected-warning{{format specifies type 'unsigned long
*' but the argument has type 'long *', which differs in signedness}}
+ scanf("%lx", x); // expected-warning{{format specifies type 'unsigned long
*' but the argument has type 'long *', which differs in signedness}}
}
void test_scanf_unsigned_long(unsigned long *x) {
- scanf("%ld", x); // expected-warning{{format specifies type 'long *' but the
argument has type 'unsigned long *'}}
+ scanf("%ld", x); // expected-warning{{format specifies type 'long *' but the
argument has type 'unsigned long *', which differs in signedness}}
scanf("%lu", x); // no-warning
scanf("%lx", x); // no-warning
}
void test_scanf_longlong(long long *x) {
scanf("%lld", x); // no-warning
- scanf("%llu", x); // expected-warning{{format specifies type 'unsigned long
long *' but the argument has type 'long long *'}}
- scanf("%llx", x); // expected-warning{{format specifies type 'unsigned long
long *' but the argument has type 'long long *'}}
+ scanf("%llu", x); // expected-warning{{format specifies type 'unsigned long
long *' but the argument has type 'long long *', which differs in signedness}}
+ scanf("%llx", x); // expected-warning{{format specifies type 'unsigned long
long *' but the argument has type 'long long *', which differs in signedness}}
}
void test_scanf_unsigned_longlong(unsigned long long *x) {
- scanf("%lld", x); // expected-warning{{format specifies type 'long long *'
but the argument has type 'unsigned long long *'}}
+ scanf("%lld", x); // expected-warning{{format specifies type 'long long *'
but the argument has type 'unsigned long long *', which differs in signedness}}
scanf("%llu", x); // no-warning
scanf("%llx", x); // no-warning
}
void test_scanf_enum_int(enum enum_int *x) {
scanf("%d", x); // no-warning
- scanf("%u", x); // expected-warning{{format specifies type 'unsigned int *'
but the argument has type 'enum enum_int *'}}
- scanf("%x", x); // expected-warning{{format specifies type 'unsigned int *'
but the argument has type 'enum enum_int *'}}
+ scanf("%u", x); // expected-warning{{format specifies type 'unsigned int *'
but the argument has type 'enum enum_int *', which differs in signedness}}
+ scanf("%x", x); // expected-warning{{format specifies type 'unsigned int *'
but the argument has type 'enum enum_int *', which differs in signedness}}
}
#ifndef _WIN32 // Disabled due to enums have different underlying type on
_WIN32
void test_scanf_enum_unsigned(enum enum_unsigned *x) {
- scanf("%d", x); // expected-warning{{format specifies type 'int *' but the
argument has type 'enum enum_unsigned *'}}
+ scanf("%d", x); // expected-warning{{format specifies type 'int *' but the
argument has type 'enum enum_unsigned *', which differs in signedness}}
scanf("%u", x); // no-warning
scanf("%x", x); // no-warning
}
void test_scanf_enum_long(enum enum_long *x) {
scanf("%ld", x); // no-warning
- scanf("%lu", x); // expected-warning{{format specifies type 'unsigned long
*' but the argument has type 'enum enum_long *'}}
- scanf("%lx", x); // expected-warning{{format specifies type 'unsigned long
*' but the argument has type 'enum enum_long *'}}
+ scanf("%lu", x); // expected-warning{{format specifies type 'unsigned long
*' but the argument has type 'enum enum_long *', which differs in signedness}}
+ scanf("%lx", x); // expected-warning{{format specifies type 'unsigned long
*' but the argument has type 'enum enum_long *', which differs in signedness}}
}
void test_scanf_enum_unsigned_long(enum enum_unsigned_long *x) {
- scanf("%ld", x); // expected-warning{{format specifies type 'long *' but the
argument has type 'enum enum_unsigned_long *'}}
+ scanf("%ld", x); // expected-warning{{format specifies type 'long *' but the
argument has type 'enum enum_unsigned_long *', which differs in signedness}}
scanf("%lu", x); // no-warning
scanf("%lx", x); // no-warning
}
>From 906679f9ef987c6e35110d0722f500b150a7cde3 Mon Sep 17 00:00:00 2001
From: Dean Sturtevant <dsturtev...@google.com>
Date: Mon, 28 Jul 2025 10:36:14 -0400
Subject: [PATCH 2/3] clang-format
---
clang/include/clang/Basic/DiagnosticSemaKinds.td | 16 +++++++++-------
clang/lib/Sema/SemaChecking.cpp | 4 ++--
2 files changed, 11 insertions(+), 9 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index dfca6577c7701..752ce93190d37 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10398,10 +10398,11 @@ def warn_format_conversion_argument_type_mismatch :
Warning<
def warn_format_conversion_argument_type_mismatch_pedantic : Extension<
warn_format_conversion_argument_type_mismatch.Summary>,
InGroup<FormatPedantic>;
-def warn_format_conversion_argument_type_mismatch_signedness : Warning<
- warn_format_conversion_argument_type_mismatch.Summary>,
- "format specifies type %0 but the argument has %select{type|underlying
type}2 %1, which differs in signedness">,
- InGroup<FormatSignedness>, DefaultIgnore;
+def warn_format_conversion_argument_type_mismatch_signedness
+ : Warning<warn_format_conversion_argument_type_mismatch.Summary>,
+ "format specifies type %0 but the argument has %select{type|underlying "
+ "type}2 %1, which differs in signedness" >
+ , InGroup<FormatSignedness>, DefaultIgnore;
def warn_format_conversion_argument_type_mismatch_confusion : Warning<
warn_format_conversion_argument_type_mismatch.Summary>,
InGroup<FormatTypeConfusion>, DefaultIgnore;
@@ -10513,9 +10514,10 @@ def warn_format_cmp_sensitivity_mismatch : Warning<
"it should be %select{unspecified|private|public|sensitive}1">,
InGroup<Format>;
def warn_format_cmp_specifier_mismatch : Warning<
"format specifier '%0' is incompatible with '%1'">, InGroup<Format>;
-def warn_format_cmp_specifier_sign_mismatch : Warning<
- "signedness of format specifier '%0' is incompatible with '%1'">,
InGroup<FormatSignedness>,
- DefaultIgnore;
+def warn_format_cmp_specifier_sign_mismatch
+ : Warning<"signedness of format specifier '%0' is incompatible with '%1'">,
+ InGroup<FormatSignedness>,
+ DefaultIgnore;
def warn_format_cmp_specifier_mismatch_pedantic : Extension<
warn_format_cmp_specifier_sign_mismatch.Summary>, InGroup<FormatPedantic>;
def note_format_cmp_with : Note<
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index bd8a8f6264d16..a9584f8273406 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -7648,8 +7648,8 @@ bool EquatableFormatArgument::VerifyCompatible(
case MK::NoMatchSignedness:
EmitDiagnostic(S,
S.PDiag(diag::warn_format_cmp_specifier_sign_mismatch)
- << buildFormatSpecifier()
- << Other.buildFormatSpecifier(),
+ << buildFormatSpecifier()
+ << Other.buildFormatSpecifier(),
FmtExpr, InFunctionCall);
HadError = S.Diag(Other.ElementLoc, diag::note_format_cmp_with)
<< 0 << Other.Range;
>From 2789319f4e38b35c4906aa89784e89248513f05d Mon Sep 17 00:00:00 2001
From: Dean Sturtevant <dsturtev...@google.com>
Date: Mon, 28 Jul 2025 10:50:36 -0400
Subject: [PATCH 3/3] Fix copy error.
---
clang/include/clang/Basic/DiagnosticSemaKinds.td | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 752ce93190d37..c02da7dba96fe 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -10398,8 +10398,7 @@ def warn_format_conversion_argument_type_mismatch :
Warning<
def warn_format_conversion_argument_type_mismatch_pedantic : Extension<
warn_format_conversion_argument_type_mismatch.Summary>,
InGroup<FormatPedantic>;
-def warn_format_conversion_argument_type_mismatch_signedness
- : Warning<warn_format_conversion_argument_type_mismatch.Summary>,
+def warn_format_conversion_argument_type_mismatch_signedness: Warning<
"format specifies type %0 but the argument has %select{type|underlying "
"type}2 %1, which differs in signedness" >
, InGroup<FormatSignedness>, DefaultIgnore;
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
