emaste created this revision.
emaste added a reviewer: DmitryPolukhin.
Herald added a reviewer: javed.absar.
Herald added subscribers: kristof.beyls, krytarowski.
When ifunc support was added to Clang (in https://reviews.llvm.org/rC265917) it
did not allow resolvers to take function arguments. This was based on GCC's
documentation, which states resolvers return a pointer and take no arguments.
However, GCC actually allows it, and glibc (on non-x86 platforms) and FreeBSD
(on x86 and arm64) pass CPU identification information as arguments to ifunc
resolvers. I believe GCC's documentation is simply incorrect / out-of-date.
We've removed the prohibition in FreeBSD's in-tree Clang:
https://svnweb.freebsd.org/changeset/base/339019.
https://reviews.llvm.org/D52703
Files:
include/clang/Basic/AttrDocs.td
include/clang/Basic/DiagnosticSemaKinds.td
lib/CodeGen/CodeGenModule.cpp
test/Sema/attr-ifunc.c
Index: test/Sema/attr-ifunc.c
===================================================================
--- test/Sema/attr-ifunc.c
+++ test/Sema/attr-ifunc.c
@@ -27,10 +27,6 @@
void f4() __attribute__((ifunc("f4_ifunc")));
//expected-error@-1 {{ifunc resolver function must return a pointer}}
-void* f5_ifunc(int i) { return 0; }
-void f5() __attribute__((ifunc("f5_ifunc")));
-//expected-error@-1 {{ifunc resolver function must have no parameters}}
-
#else
void f1a() __asm("f1");
void f1a() {}
Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -322,8 +322,6 @@
assert(FTy);
if (!FTy->getReturnType()->isPointerTy())
Diags.Report(Location, diag::err_ifunc_resolver_return);
- if (FTy->getNumParams())
- Diags.Report(Location, diag::err_ifunc_resolver_params);
}
llvm::Constant *Aliasee = Alias->getIndirectSymbol();
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -2887,8 +2887,6 @@
"%select{alias|ifunc}0 definition is part of a cycle">;
def err_ifunc_resolver_return : Error<
"ifunc resolver function must return a pointer">;
-def err_ifunc_resolver_params : Error<
- "ifunc resolver function must have no parameters">;
def warn_attribute_wrong_decl_type_str : Warning<
"%0 attribute only applies to %1">, InGroup<IgnoredAttributes>;
def err_attribute_wrong_decl_type_str : Error<
Index: include/clang/Basic/AttrDocs.td
===================================================================
--- include/clang/Basic/AttrDocs.td
+++ include/clang/Basic/AttrDocs.td
@@ -3366,7 +3366,7 @@
let Content = [{
``__attribute__((ifunc("resolver")))`` is used to mark that the address of a
declaration should be resolved at runtime by calling a resolver function.
-The symbol name of the resolver function is given in quotes. A function with
this name (after mangling) must be defined in the current translation unit; it
may be ``static``. The resolver function should take no arguments and return a
pointer.
+The symbol name of the resolver function is given in quotes. A function with
this name (after mangling) must be defined in the current translation unit; it
may be ``static``. The resolver function should return a pointer.
The ``ifunc`` attribute may only be used on a function declaration. A
function declaration with an ``ifunc`` attribute is considered to be a
definition of the declared entity. The entity must not have weak linkage; for
example, in C++, it cannot be applied to a declaration if a definition at that
location would be considered inline.
Index: test/Sema/attr-ifunc.c
===================================================================
--- test/Sema/attr-ifunc.c
+++ test/Sema/attr-ifunc.c
@@ -27,10 +27,6 @@
void f4() __attribute__((ifunc("f4_ifunc")));
//expected-error@-1 {{ifunc resolver function must return a pointer}}
-void* f5_ifunc(int i) { return 0; }
-void f5() __attribute__((ifunc("f5_ifunc")));
-//expected-error@-1 {{ifunc resolver function must have no parameters}}
-
#else
void f1a() __asm("f1");
void f1a() {}
Index: lib/CodeGen/CodeGenModule.cpp
===================================================================
--- lib/CodeGen/CodeGenModule.cpp
+++ lib/CodeGen/CodeGenModule.cpp
@@ -322,8 +322,6 @@
assert(FTy);
if (!FTy->getReturnType()->isPointerTy())
Diags.Report(Location, diag::err_ifunc_resolver_return);
- if (FTy->getNumParams())
- Diags.Report(Location, diag::err_ifunc_resolver_params);
}
llvm::Constant *Aliasee = Alias->getIndirectSymbol();
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -2887,8 +2887,6 @@
"%select{alias|ifunc}0 definition is part of a cycle">;
def err_ifunc_resolver_return : Error<
"ifunc resolver function must return a pointer">;
-def err_ifunc_resolver_params : Error<
- "ifunc resolver function must have no parameters">;
def warn_attribute_wrong_decl_type_str : Warning<
"%0 attribute only applies to %1">, InGroup<IgnoredAttributes>;
def err_attribute_wrong_decl_type_str : Error<
Index: include/clang/Basic/AttrDocs.td
===================================================================
--- include/clang/Basic/AttrDocs.td
+++ include/clang/Basic/AttrDocs.td
@@ -3366,7 +3366,7 @@
let Content = [{
``__attribute__((ifunc("resolver")))`` is used to mark that the address of a declaration should be resolved at runtime by calling a resolver function.
-The symbol name of the resolver function is given in quotes. A function with this name (after mangling) must be defined in the current translation unit; it may be ``static``. The resolver function should take no arguments and return a pointer.
+The symbol name of the resolver function is given in quotes. A function with this name (after mangling) must be defined in the current translation unit; it may be ``static``. The resolver function should return a pointer.
The ``ifunc`` attribute may only be used on a function declaration. A function declaration with an ``ifunc`` attribute is considered to be a definition of the declared entity. The entity must not have weak linkage; for example, in C++, it cannot be applied to a declaration if a definition at that location would be considered inline.
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