From 8bddfdd59ce2e76d0c99785a3838d4b28fd556b3 Mon Sep 17 00:00:00 2001 From: Ed Maste Date: Wed, 10 Oct 2018 00:34:17 +0000 Subject: [PATCH] clang: Allow ifunc resolvers to accept arguments When ifunc support was added to Clang (r265917) 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 resolvers to take arguments, and glibc (on non-x86 platforms) and FreeBSD (on x86 and arm64) pass some CPU identification information as arguments to ifunc resolvers. I believe GCC's documentation is simply incorrect / out-of-date. FreeBSD already removed the prohibition in their in-tree Clang copy. Differential Revision: https://reviews.llvm.org/D52703 llvm-svn: 344100 --- clang/include/clang/Basic/AttrDocs.td | 2 +- clang/include/clang/Basic/DiagnosticSemaKinds.td | 2 -- clang/lib/CodeGen/CodeGenModule.cpp | 2 -- clang/test/Sema/attr-ifunc.c | 4 ---- 4 files changed, 1 insertion(+), 9 deletions(-) diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td index a90cb96c07cd..02eac41868a1 100644 --- a/clang/include/clang/Basic/AttrDocs.td +++ b/clang/include/clang/Basic/AttrDocs.td @@ -3428,7 +3428,7 @@ def IFuncDocs : Documentation { 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. diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 2bab1ec322b8..b00e8b1ad6c8 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -2889,8 +2889,6 @@ def err_cyclic_alias : Error< "%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; def err_attribute_wrong_decl_type_str : Error< diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index dbea1fc7112b..12ed65cf2675 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -322,8 +322,6 @@ void CodeGenModule::checkAliases() { 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(); diff --git a/clang/test/Sema/attr-ifunc.c b/clang/test/Sema/attr-ifunc.c index af7a7e33da09..907b61c4451e 100644 --- a/clang/test/Sema/attr-ifunc.c +++ b/clang/test/Sema/attr-ifunc.c @@ -27,10 +27,6 @@ void f4_ifunc() {} 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() {}