This patch adds to new backend hooks
ASM_OUTPUT_START_FUNCTION_HEADER and
ASM_OUTPUT_END_FUNCTION_FOOTER that may be defined to emit
assembly code at the very start or end of a function. This
functionality is needed by the patch that ports the "target"
attribute and pragma to S/390. (I'll post that patch shortly, and
in a different thread.)
Note that a function may need to switch to a different section in
the .s file (hot/cold section or whatever). The additional code
is (arguably) emitted *before* switching the section. That seems
to be more correct to me that emitting it after the switch, but
it's not a big deal to change that.
Ciao
Dominik ^_^ ^_^
--
Dominik Vogt
IBM Germany
gcc/ChangeLog
* defaults.h (ASM_OUTPUT_START_FUNCTION_HEADER): New hook function.
(ASM_OUTPUT_START_FUNCTION_FOOTER): Ditto.
* varasm.c (assemble_start_function): Call new hook at start of
function.
(assemble_end_function): Call new hook at end of function.
* doc/tm.texi.in: Document new hook functions.
>From 61c2546ba0aa0e9b2743f8d64427143aac5af2b0 Mon Sep 17 00:00:00 2001
From: Dominik Vogt <v...@linux.vnet.ibm.com>
Date: Wed, 29 Jul 2015 16:14:23 +0100
Subject: [PATCH] Add new hooks ASM_OUTPUT_START_FUNCTION_HEADER ...
and ASM_OUTPUT_END_FUNCTION_FOOTER. These are used by the implementation of
__attribute__ ((target(...))) on S390.
---
gcc/defaults.h | 10 ++++++++++
gcc/doc/tm.texi | 14 ++++++++++++++
gcc/doc/tm.texi.in | 14 ++++++++++++++
gcc/varasm.c | 2 ++
4 files changed, 40 insertions(+)
diff --git a/gcc/defaults.h b/gcc/defaults.h
index d4d3a56..aa9c849 100644
--- a/gcc/defaults.h
+++ b/gcc/defaults.h
@@ -135,6 +135,16 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#define TARGET_DEFERRED_OUTPUT_DEFS(DECL,TARGET) false
#endif
+/* Output additional assemler code at the very start of the function. */
+#ifndef ASM_OUTPUT_START_FUNCTION_HEADER
+#define ASM_OUTPUT_START_FUNCTION_HEADER(FILE,DECL) do { } while (0)
+#endif
+
+/* Output additional assemler code at the very end of the function. */
+#ifndef ASM_OUTPUT_END_FUNCTION_FOOTER
+#define ASM_OUTPUT_START_FUNCTION_FOOTER(FILE,DECL) do { } while (0)
+#endif
+
/* This is how to output the definition of a user-level label named
NAME, such as the label on variable NAME. */
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index d548d96..7ba00c3 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -7917,6 +7917,20 @@ If you define @code{TYPE_ASM_OP} and @code{TYPE_OPERAND_FMT}, a default
definition of this macro is provided.
@end defmac
+@defmac ASM_OUTPUT_START_FUNCTION_HEADER (@var{stream}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} additional assembly language code to be placed at the
+very start of the current function. The default definition of this
+macro does nothing.
+@end defmac
+
+@defmac ASM_OUTPUT_END_FUNCTION_FOOTER (@var{stream}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} additional assembly language code at the very end of
+the current function. The default definition of this macro does
+nothing.
+@end defmac
+
@defmac ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name @var{name} of a
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 9bef4a5..2b2b7e4 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -5546,6 +5546,20 @@ If you define @code{TYPE_ASM_OP} and @code{TYPE_OPERAND_FMT}, a default
definition of this macro is provided.
@end defmac
+@defmac ASM_OUTPUT_START_FUNCTION_HEADER (@var{stream}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} additional assembly language code to be placed at the
+very start of the current function. The default definition of this
+macro does nothing.
+@end defmac
+
+@defmac ASM_OUTPUT_END_FUNCTION_FOOTER (@var{stream}, @var{decl})
+A C statement (sans semicolon) to output to the stdio stream
+@var{stream} additional assembly language code at the very end of
+the current function. The default definition of this macro does
+nothing.
+@end defmac
+
@defmac ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
A C statement (sans semicolon) to output to the stdio stream
@var{stream} any text necessary for declaring the name @var{name} of a
diff --git a/gcc/varasm.c b/gcc/varasm.c
index 706e652..dcee8f0 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -1701,6 +1701,7 @@ assemble_start_function (tree decl, const char *fnname)
char tmp_label[100];
bool hot_label_written = false;
+ ASM_OUTPUT_START_FUNCTION_HEADER (asm_out_file, current_function_decl);
if (flag_reorder_blocks_and_partition)
{
ASM_GENERATE_INTERNAL_LABEL (tmp_label, "LHOTB", const_labelno);
@@ -1864,6 +1865,7 @@ assemble_end_function (tree decl, const char *fnname ATTRIBUTE_UNUSED)
ASM_OUTPUT_LABEL (asm_out_file, crtl->subsections.hot_section_end_label);
switch_to_section (save_text_section);
}
+ ASM_OUTPUT_END_FUNCTION_FOOTER (asm_out_file, current_function_decl);
}
/* Assemble code to leave SIZE bytes of zeros. */
--
2.3.0
