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C++ PATCH: Builtins (3 of 3)
- To: gcc-patches at gcc dot gnu dot org
- Subject: C++ PATCH: Builtins (3 of 3)
- From: Mark Mitchell <mark at codesourcery dot com>
- Date: Thu, 24 May 2001 18:23:26 -0700
- Organization: CodeSourcery, LLC
This patch changes the C++ compiler to never define builtins that do
not begin with `__builtin'.
Tested on i686-pc-linux-gnu, installed on the mainline and on the
branch.
--
Mark Mitchell mark@codesourcery.com
CodeSourcery, LLC http://www.codesourcery.com
2001-05-24 Mark Mitchell <mark@codesourcery.com>
* invoke.texi (-fno-builtin): Document that this is always on
in C++.
2001-05-24 Mark Mitchell <mark@codesourcery.com>
* decl.c (duplicate_decls): Tidy.
(init_decl_processing): Always set flag_no_builtin.
Index: gcc/invoke.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/invoke.texi,v
retrieving revision 1.273.2.22
diff -c -p -r1.273.2.22 invoke.texi
*** invoke.texi 2001/05/21 15:57:55 1.273.2.22
--- invoke.texi 2001/05/25 00:56:01
*************** and faster, but since the function calls
*** 978,983 ****
--- 978,990 ----
cannot set a breakpoint on those calls, nor can you change the behavior
of the functions by linking with a different library.
+ In C++, @samp{-fno-builtin} is always in effect. The @samp{-fbuiltin}
+ option has no effect. Therefore, in C++, the only way to get the
+ optimization benefits of builtin functions is to call the function
+ using the @samp{__builtin_} prefix. The GNU C++ Standard Library uses
+ builtin functions to implement many functions (like
+ @code{std::strchr}), so that you automatically get efficient code.
+
@item -fhosted
@cindex hosted environment
Index: gcc/cp/decl.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/decl.c,v
retrieving revision 1.747.2.26
diff -c -p -r1.747.2.26 decl.c
*** decl.c 2001/05/13 07:10:20 1.747.2.26
--- decl.c 2001/05/25 00:56:07
*************** duplicate_decls (newdecl, olddecl)
*** 3722,3733 ****
DECL_ARGUMENTS (newdecl) = DECL_ARGUMENTS (olddecl);
}
}
- if (TREE_CODE (newdecl) == NAMESPACE_DECL)
- {
- NAMESPACE_LEVEL (newdecl) = NAMESPACE_LEVEL (olddecl);
- }
-
/* Now preserve various other info from the definition. */
TREE_ADDRESSABLE (newdecl) = TREE_ADDRESSABLE (olddecl);
TREE_ASM_WRITTEN (newdecl) = TREE_ASM_WRITTEN (olddecl);
--- 3722,3730 ----
DECL_ARGUMENTS (newdecl) = DECL_ARGUMENTS (olddecl);
}
}
+ else if (TREE_CODE (newdecl) == NAMESPACE_DECL)
+ NAMESPACE_LEVEL (newdecl) = NAMESPACE_LEVEL (olddecl);
/* Now preserve various other info from the definition. */
TREE_ADDRESSABLE (newdecl) = TREE_ADDRESSABLE (olddecl);
TREE_ASM_WRITTEN (newdecl) = TREE_ASM_WRITTEN (olddecl);
*************** init_decl_processing ()
*** 6375,6380 ****
--- 6372,6383 ----
flag_inline_trees = 2;
flag_inline_functions = 0;
}
+
+ /* In C++, we never create builtin functions whose name does not
+ begin with `__'. Users should be using headers to get prototypes
+ in C++. It would be nice if we could warn when `-fbuiltin' is
+ used explicitly, but we do not have that information. */
+ flag_no_builtin = 1;
/* Initially, C. */
current_lang_name = lang_name_c;