[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
MaskRay wrote:
> Presumably similar things might show up in macros? But can cross that bridge
> when we come to it.
>
> Perhaps we have some/could use some generic utility for this sort of
> contextual warning "if these things are literally written next to each other,
> warn, but if they came to be via template instantiation, macro, (something
> else?) then don't" because that sort of situation shows up pretty regularly
> in diagnostics, I think...
I modeled the template instantiation suppression after
`diagnoseTautologicalComparison`.
While some macro uses suppress `diagnoseTautologicalComparison` diagnostics,
e.g.
```
// Don't issue a warning when either the left or right side of the comparison
// results from a macro expansion.
#define R8435950_A i
#define R8435950_B i
int R8435950(int i) {
if (R8435950_A == R8435950_B) // no-warning
return 0;
return 1;
}
```
some have diagnostics (e.g. https://reviews.llvm.org/D70624). Yes, we can cross
that bridge when we come to it.
https://github.com/llvm/llvm-project/pull/83497
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[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
dwblaikie wrote: Presumably similar things might show up in macros? But can cross that bridge when we come to it. Perhaps we have some/could use some generic utility for this sort of contextual warning "if these things are literally written next to each other, warn, but if they came to be via template instantiation, macro, (something else?) then don't" because that sort of situation shows up pretty regularly in diagnostics, I think... https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
https://github.com/MaskRay closed https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
@@ -92,6 +92,19 @@ void foo() {
bool is_true = [](){ return true; };
// expected-warning@-1{{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
}
+
+template
+static bool IsFalse(const Ts&...) { return false; }
+template
+static bool IsFalse(const T& p) {
+ bool b;
+ b = f7; // expected-warning {{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
+ return p ? false : true;
MaskRay wrote:
Thanks for the suggestion! Adjusted to 80-col.
https://github.com/llvm/llvm-project/pull/83497
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[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
https://github.com/MaskRay updated
https://github.com/llvm/llvm-project/pull/83497
>From d7a168190f2fdf3b4f8ec1457400ad8e03bc3f3a Mon Sep 17 00:00:00 2001
From: Fangrui Song
Date: Thu, 29 Feb 2024 14:40:00 -0800
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
=?UTF-8?q?l=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Created using spr 1.3.4
---
clang/lib/Sema/SemaChecking.cpp | 17 ++---
clang/test/SemaCXX/warn-bool-conversion.cpp | 13 +
2 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 690bdaa63d058b..3533b5c8e0d235 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -16586,13 +16586,16 @@ void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
}
// Complain if we are converting a lambda expression to a boolean value
- if (const auto *MCallExpr = dyn_cast(E)) {
-if (const auto *MRecordDecl = MCallExpr->getRecordDecl();
-MRecordDecl && MRecordDecl->isLambda()) {
- Diag(E->getExprLoc(), diag::warn_impcast_pointer_to_bool)
- << /*LambdaPointerConversionOperatorType=*/3
- << MRecordDecl->getSourceRange() << Range << IsEqual;
- return;
+ // outside of instantiation.
+ if (!inTemplateInstantiation()) {
+if (const auto *MCallExpr = dyn_cast(E)) {
+ if (const auto *MRecordDecl = MCallExpr->getRecordDecl();
+ MRecordDecl && MRecordDecl->isLambda()) {
+Diag(E->getExprLoc(), diag::warn_impcast_pointer_to_bool)
+<< /*LambdaPointerConversionOperatorType=*/3
+<< MRecordDecl->getSourceRange() << Range << IsEqual;
+return;
+ }
}
}
diff --git a/clang/test/SemaCXX/warn-bool-conversion.cpp
b/clang/test/SemaCXX/warn-bool-conversion.cpp
index 9e8cf0e4f8944a..8b1bf80af79d26 100644
--- a/clang/test/SemaCXX/warn-bool-conversion.cpp
+++ b/clang/test/SemaCXX/warn-bool-conversion.cpp
@@ -92,6 +92,19 @@ void foo() {
bool is_true = [](){ return true; };
// expected-warning@-1{{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
}
+
+template
+static bool IsFalse(const Ts&...) { return false; }
+template
+static bool IsFalse(const T& p) {
+ bool b;
+ b = f7; // expected-warning {{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
+ return p ? false : true;
+}
+
+bool use_instantiation() {
+ return IsFalse([]() { return 0; });
+}
#endif
void bar() {
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[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
https://github.com/MaskRay edited https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
vinayakdsci wrote: Great catch! The usage of template instantiation didn't seem very obvious while adding the tests, and hence the missed test case. Thanks a lot for the fix! https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
https://github.com/AaronBallman approved this pull request. LGTM with a minor commenting nit. Thank you for catching this and the quick patch! https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
@@ -92,6 +92,19 @@ void foo() {
bool is_true = [](){ return true; };
// expected-warning@-1{{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
}
+
+template
+static bool IsFalse(const Ts&...) { return false; }
+template
+static bool IsFalse(const T& p) {
+ bool b;
+ b = f7; // expected-warning {{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
+ return p ? false : true;
AaronBallman wrote:
```suggestion
// Intentionally not warned on because p could be a lambda type in one
instantiation, but a pointer
// type in another.
return p ? false : true;
```
(May need to adjust for 80-col limits.)
https://github.com/llvm/llvm-project/pull/83497
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[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
https://github.com/AaronBallman edited https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
https://github.com/MaskRay edited https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
MaskRay wrote: @vinayakdsci https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
https://github.com/MaskRay edited https://github.com/llvm/llvm-project/pull/83497 ___ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
llvmbot wrote:
@llvm/pr-subscribers-clang
Author: Fangrui Song (MaskRay)
Changes
I have seen internal pieces of code that uses a template type parameter
to accept std::function, a closure type, or any callable type. The
diagnostic added in #83152 would require adaptation to the template,
which is difficult and also seems unnecessary.
```cpp
template typename... Ts
static bool IsFalse(const Ts...) { return false; }
template typename T, typename... Ts,
typename = typename std::enable_ifstd::is_constructiblebool,
const T::value::type
static bool IsFalse(const Partial, const T p, const Ts...) {
return p ? false : true;
}
template typename... Args
void Init(Args... args) {
if (IsFalse(absl::implicit_castconst typename
std::decayArgs::type(
args)...)) {
// A callable object convertible to false is either a null pointer or a
// null functor (e.g., a default-constructed std::function).
empty_ = true;
} else {
empty_ = false;
new (factory_) Factory(std::forwardArgs(args)...);
}
}
```
---
Full diff: https://github.com/llvm/llvm-project/pull/83497.diff
2 Files Affected:
- (modified) clang/lib/Sema/SemaChecking.cpp (+10-7)
- (modified) clang/test/SemaCXX/warn-bool-conversion.cpp (+13)
``diff
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 690bdaa63d058b..3533b5c8e0d235 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -16586,13 +16586,16 @@ void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
}
// Complain if we are converting a lambda expression to a boolean value
- if (const auto *MCallExpr = dyn_cast(E)) {
-if (const auto *MRecordDecl = MCallExpr->getRecordDecl();
-MRecordDecl && MRecordDecl->isLambda()) {
- Diag(E->getExprLoc(), diag::warn_impcast_pointer_to_bool)
- << /*LambdaPointerConversionOperatorType=*/3
- << MRecordDecl->getSourceRange() << Range << IsEqual;
- return;
+ // outside of instantiation.
+ if (!inTemplateInstantiation()) {
+if (const auto *MCallExpr = dyn_cast(E)) {
+ if (const auto *MRecordDecl = MCallExpr->getRecordDecl();
+ MRecordDecl && MRecordDecl->isLambda()) {
+Diag(E->getExprLoc(), diag::warn_impcast_pointer_to_bool)
+<< /*LambdaPointerConversionOperatorType=*/3
+<< MRecordDecl->getSourceRange() << Range << IsEqual;
+return;
+ }
}
}
diff --git a/clang/test/SemaCXX/warn-bool-conversion.cpp
b/clang/test/SemaCXX/warn-bool-conversion.cpp
index 9e8cf0e4f8944a..8b1bf80af79d26 100644
--- a/clang/test/SemaCXX/warn-bool-conversion.cpp
+++ b/clang/test/SemaCXX/warn-bool-conversion.cpp
@@ -92,6 +92,19 @@ void foo() {
bool is_true = [](){ return true; };
// expected-warning@-1{{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
}
+
+template
+static bool IsFalse(const Ts&...) { return false; }
+template
+static bool IsFalse(const T& p) {
+ bool b;
+ b = f7; // expected-warning {{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
+ return p ? false : true;
+}
+
+bool use_instantiation() {
+ return IsFalse([]() { return 0; });
+}
#endif
void bar() {
``
https://github.com/llvm/llvm-project/pull/83497
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[clang] [Sema] -Wpointer-bool-conversion: suppress lambda function pointer conversion diagnostic during instantiation (PR #83497)
https://github.com/MaskRay created
https://github.com/llvm/llvm-project/pull/83497
I have seen internal pieces of code that uses a template type parameter
to accept std::function, a closure type, or any callable type. The
diagnostic added in #83152 would require adaptation to the template,
which is difficult and also seems unnecessary.
```cpp
template
static bool IsFalse(const Ts&...) { return false; }
template ::value>::type>
static bool IsFalse(const Partial&, const T& p, const Ts&...) {
return p ? false : true;
}
template
void Init(Args&&... args) {
if (IsFalse(absl::implicit_cast::type&>(
args)...)) {
// A callable object convertible to false is either a null pointer or a
// null functor (e.g., a default-constructed std::function).
empty_ = true;
} else {
empty_ = false;
new (_) Factory(std::forward(args)...);
}
}
```
>From d7a168190f2fdf3b4f8ec1457400ad8e03bc3f3a Mon Sep 17 00:00:00 2001
From: Fangrui Song
Date: Thu, 29 Feb 2024 14:40:00 -0800
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
=?UTF-8?q?l=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Created using spr 1.3.4
---
clang/lib/Sema/SemaChecking.cpp | 17 ++---
clang/test/SemaCXX/warn-bool-conversion.cpp | 13 +
2 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 690bdaa63d058b..3533b5c8e0d235 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -16586,13 +16586,16 @@ void Sema::DiagnoseAlwaysNonNullPointer(Expr *E,
}
// Complain if we are converting a lambda expression to a boolean value
- if (const auto *MCallExpr = dyn_cast(E)) {
-if (const auto *MRecordDecl = MCallExpr->getRecordDecl();
-MRecordDecl && MRecordDecl->isLambda()) {
- Diag(E->getExprLoc(), diag::warn_impcast_pointer_to_bool)
- << /*LambdaPointerConversionOperatorType=*/3
- << MRecordDecl->getSourceRange() << Range << IsEqual;
- return;
+ // outside of instantiation.
+ if (!inTemplateInstantiation()) {
+if (const auto *MCallExpr = dyn_cast(E)) {
+ if (const auto *MRecordDecl = MCallExpr->getRecordDecl();
+ MRecordDecl && MRecordDecl->isLambda()) {
+Diag(E->getExprLoc(), diag::warn_impcast_pointer_to_bool)
+<< /*LambdaPointerConversionOperatorType=*/3
+<< MRecordDecl->getSourceRange() << Range << IsEqual;
+return;
+ }
}
}
diff --git a/clang/test/SemaCXX/warn-bool-conversion.cpp
b/clang/test/SemaCXX/warn-bool-conversion.cpp
index 9e8cf0e4f8944a..8b1bf80af79d26 100644
--- a/clang/test/SemaCXX/warn-bool-conversion.cpp
+++ b/clang/test/SemaCXX/warn-bool-conversion.cpp
@@ -92,6 +92,19 @@ void foo() {
bool is_true = [](){ return true; };
// expected-warning@-1{{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
}
+
+template
+static bool IsFalse(const Ts&...) { return false; }
+template
+static bool IsFalse(const T& p) {
+ bool b;
+ b = f7; // expected-warning {{address of lambda function pointer conversion
operator will always evaluate to 'true'}}
+ return p ? false : true;
+}
+
+bool use_instantiation() {
+ return IsFalse([]() { return 0; });
+}
#endif
void bar() {
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