aaron.ballman created this revision.
aaron.ballman added reviewers: efriedma, jyknight, clang-language-wg.
Herald added a project: All.
aaron.ballman requested review of this revision.
Herald added a project: clang.
As was observed in https://reviews.llvm.org/D123627#3707635, it's confusing
that a user can write:
float rintf(void) {}
and get a warning, but writing:
float rintf() {}
gives an error. This patch changes the behavior so that both are warnings, so
that users who have functions which conflict with a builtin identifier can
still use that identifier as they wish.
Note, if we accept this, I would like to backport it to the Clang 15.x branch
because the original change was made in Clang 15.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D131499
Files:
clang/lib/Sema/SemaDecl.cpp
clang/test/Sema/prototype-redecls.c
Index: clang/test/Sema/prototype-redecls.c
===================================================================
--- clang/test/Sema/prototype-redecls.c
+++ clang/test/Sema/prototype-redecls.c
@@ -29,7 +29,7 @@
// Ensure redeclarations that conflict with a builtin use a note which makes it
// clear that the previous declaration was a builtin.
-float rintf() { // expected-error {{conflicting types for 'rintf'}} \
+float rintf() { // expected-warning {{incompatible redeclaration of library
function 'rintf'}} \
expected-note {{'rintf' is a builtin with type 'float
(float)'}}
return 1.0f;
}
Index: clang/lib/Sema/SemaDecl.cpp
===================================================================
--- clang/lib/Sema/SemaDecl.cpp
+++ clang/lib/Sema/SemaDecl.cpp
@@ -4042,7 +4042,7 @@
// default argument promotion rules were already checked by
// ASTContext::typesAreCompatible().
if (Old->hasPrototype() && !New->hasWrittenPrototype() && NewDeclIsDefn &&
- Old->getNumParams() != New->getNumParams()) {
+ Old->getNumParams() != New->getNumParams() && !Old->isImplicit()) {
if (Old->hasInheritedPrototype())
Old = Old->getCanonicalDecl();
Diag(New->getLocation(), diag::err_conflicting_types) << New;
Index: clang/test/Sema/prototype-redecls.c
===================================================================
--- clang/test/Sema/prototype-redecls.c
+++ clang/test/Sema/prototype-redecls.c
@@ -29,7 +29,7 @@
// Ensure redeclarations that conflict with a builtin use a note which makes it
// clear that the previous declaration was a builtin.
-float rintf() { // expected-error {{conflicting types for 'rintf'}} \
+float rintf() { // expected-warning {{incompatible redeclaration of library function 'rintf'}} \
expected-note {{'rintf' is a builtin with type 'float (float)'}}
return 1.0f;
}
Index: clang/lib/Sema/SemaDecl.cpp
===================================================================
--- clang/lib/Sema/SemaDecl.cpp
+++ clang/lib/Sema/SemaDecl.cpp
@@ -4042,7 +4042,7 @@
// default argument promotion rules were already checked by
// ASTContext::typesAreCompatible().
if (Old->hasPrototype() && !New->hasWrittenPrototype() && NewDeclIsDefn &&
- Old->getNumParams() != New->getNumParams()) {
+ Old->getNumParams() != New->getNumParams() && !Old->isImplicit()) {
if (Old->hasInheritedPrototype())
Old = Old->getCanonicalDecl();
Diag(New->getLocation(), diag::err_conflicting_types) << New;
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