Add function_abi.{h,cc}

This patch adds new structures and functions for handling
multiple ABIs in a translation unit.  The structures are:

- predefined_function_abi: describes a static, predefined ABI
- function_abi: describes either a predefined ABI or a local
  variant of one (e.g. taking -fipa-ra into account)

The patch adds functions for getting the ABI from a given type
or decl; a later patch will also add a function for getting the
ABI of the target of a call insn.

Although ABIs are about much more than call-clobber/saved choices,
I wanted to keep the name general in case we add more ABI-related
information in future.

2019-09-30  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* Makefile.in (OBJS): Add function-abi.o.
	(GTFILES): Add function-abi.h.
	* function-abi.cc: New file.
	* function-abi.h: Likewise.
	* emit-rtl.h (rtl_data::abi): New field.
	* function.c: Include function-abi.h.
	(prepare_function_start): Initialize crtl->abi.
	* read-rtl-function.c: Include regs.h and function-abi.h.
	(read_rtl_function_body): Initialize crtl->abi.
	(read_rtl_function_body_from_file_range): Likewise.
	* reginfo.c: Include function-abi.h.
	(init_reg_sets_1): Initialize default_function_abi.
	(globalize_reg): Call add_full_reg_clobber for each predefined ABI
	when making a register global.
	* target-globals.h (this_target_function_abi_info): Declare.
	(target_globals::function_abi_info): New field.
	(restore_target_globals): Copy it.
	* target-globals.c: Include function-abi.h.
	(default_target_globals): Initialize the function_abi_info field.
	(target_globals): Allocate it.
	(save_target_globals): Free it.

From-SVN: r276307

1 files changed, 7 insertions, 0 deletions

diff --git a/gcc/function.c b/gcc/function.c
index 9c158cec121..c3aa6a5e9c5 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -79,6 +79,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "attribs.h"
 #include "gimple.h"
 #include "options.h"
+#include "function-abi.h"
 
 /* So we can assign to cfun in this file.  */
 #undef cfun
@@ -4826,6 +4827,12 @@ static void
 prepare_function_start (void)
 {
   gcc_assert (!get_last_insn ());
+
+  if (in_dummy_function)
+    crtl->abi = &default_function_abi;
+  else
+    crtl->abi = &fndecl_abi (cfun->decl).base_abi ();
+
   init_temp_slots ();
   init_emit ();
   init_varasm_status ();