Add a function for getting the ABI of a call insn target

This patch replaces get_call_reg_set_usage with insn_callee_abi,
which returns the ABI of the target of a call insn.  The ABI's
full_reg_clobbers corresponds to regs_invalidated_by_call,
whereas many callers instead passed call_used_or_fixed_regs, i.e.:

  (regs_invalidated_by_call | fixed_reg_set)

The patch slavishly preserves the "| fixed_reg_set" for these callers;
later patches will clean this up.

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

gcc/
	* target.def (insn_callee_abi): New hook.
	(remove_extra_call_preserved_regs): Delete.
	* doc/tm.texi.in (TARGET_INSN_CALLEE_ABI): New macro.
	(TARGET_REMOVE_EXTRA_CALL_PRESERVED_REGS): Delete.
	* doc/tm.texi: Regenerate.
	* targhooks.h (default_remove_extra_call_preserved_regs): Delete.
	* targhooks.c (default_remove_extra_call_preserved_regs): Delete.
	* config/aarch64/aarch64.c (aarch64_simd_call_p): Constify the
	insn argument.
	(aarch64_remove_extra_call_preserved_regs): Delete.
	(aarch64_insn_callee_abi): New function.
	(TARGET_REMOVE_EXTRA_CALL_PRESERVED_REGS): Delete.
	(TARGET_INSN_CALLEE_ABI): New macro.
	* rtl.h (get_call_fndecl): Declare.
	(cgraph_rtl_info): Fix formatting.  Tweak comment for
	function_used_regs.  Remove function_used_regs_valid.
	* rtlanal.c (get_call_fndecl): Moved from final.c
	* function-abi.h (insn_callee_abi): Declare.
	(target_function_abi_info): Mention insn_callee_abi.
	* function-abi.cc (fndecl_abi): Handle flag_ipa_ra in a similar
	way to get_call_reg_set_usage did.
	(insn_callee_abi): New function.
	* regs.h (get_call_reg_set_usage): Delete.
	* final.c: Include function-abi.h.
	(collect_fn_hard_reg_usage): Add fixed and stack registers to
	function_used_regs before the main loop rather than afterwards.
	Use insn_callee_abi instead of get_call_reg_set_usage.  Exit early
	if function_used_regs ends up not being useful.
	(get_call_fndecl): Move to rtlanal.c
	(get_call_cgraph_rtl_info, get_call_reg_set_usage): Delete.
	* caller-save.c: Include function-abi.h.
	(setup_save_areas, save_call_clobbered_regs): Use insn_callee_abi
	instead of get_call_reg_set_usage.
	* cfgcleanup.c: Include function-abi.h.
	(old_insns_match_p): Use insn_callee_abi instead of
	get_call_reg_set_usage.
	* cgraph.h (cgraph_node::rtl_info): Take a const_tree instead of
	a tree.
	* cgraph.c (cgraph_node::rtl_info): Likewise.  Initialize
	function_used_regs.
	* df-scan.c: Include function-abi.h.
	(df_get_call_refs): Use insn_callee_abi instead of
	get_call_reg_set_usage.
	* ira-lives.c: Include function-abi.h.
	(process_bb_node_lives): Use insn_callee_abi instead of
	get_call_reg_set_usage.
	* lra-lives.c: Include function-abi.h.
	(process_bb_lives): Use insn_callee_abi instead of
	get_call_reg_set_usage.
	* postreload.c: Include function-abi.h.
	(reload_combine): Use insn_callee_abi instead of
	get_call_reg_set_usage.
	* regcprop.c: Include function-abi.h.
	(copyprop_hardreg_forward_1): Use insn_callee_abi instead of
	get_call_reg_set_usage.
	* resource.c: Include function-abi.h.
	(mark_set_resources, mark_target_live_regs): Use insn_callee_abi
	instead of get_call_reg_set_usage.
	* var-tracking.c: Include function-abi.h.
	(dataflow_set_clear_at_call): Use insn_callee_abi instead of
	get_call_reg_set_usage.

From-SVN: r276309

2 files changed, 13 insertions, 14 deletions

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 0f79d38..33997a5 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -1905,6 +1905,17 @@ descriptor.  Targets only need to define this hook if they support
 interoperability between several ABIs in the same translation unit.
 @end deftypefn
 
+@deftypefn {Target Hook} {const predefined_function_abi &} TARGET_INSN_CALLEE_ABI (const rtx_insn *@var{insn})
+This hook returns a description of the ABI used by the target of
+call instruction @var{insn}; see the definition of
+@code{predefined_function_abi} for details of the ABI descriptor.
+Only the global function @code{insn_callee_abi} should call this hook
+directly.
+
+Targets only need to define this hook if they support
+interoperability between several ABIs in the same translation unit.
+@end deftypefn
+
 @cindex call-used register
 @cindex call-clobbered register
 @cindex call-saved register
@@ -1921,18 +1932,6 @@ The default implementation returns false, which is correct
 for targets that don't have partly call-clobbered registers.
 @end deftypefn
 
-@deftypefn {Target Hook} void TARGET_REMOVE_EXTRA_CALL_PRESERVED_REGS (rtx_insn *@var{insn}, HARD_REG_SET *@var{used_regs})
-This hook removes registers from the set of call-clobbered registers
- in @var{used_regs} if, contrary to the default rules, something guarantees
- that @samp{insn} preserves those registers.  For example, some targets
- support variant ABIs in which functions preserve more registers than
- normal functions would.  Removing those extra registers from @var{used_regs}
- can lead to better register allocation.
- 
- The default implementation does nothing, which is always safe.
- Defining the hook is purely an optimization.
-@end deftypefn
-
 @deftypefn {Target Hook} {rtx_insn *} TARGET_RETURN_CALL_WITH_MAX_CLOBBERS (rtx_insn *@var{call_1}, rtx_insn *@var{call_2})
 This hook returns a pointer to the call that partially clobbers the
 most registers.  If a platform supports multiple ABIs where the registers
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index ed605c0..55fb5d4 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -1711,13 +1711,13 @@ must be defined.  Modern ports should define @code{CALL_REALLY_USED_REGISTERS}.
 @cindex call-saved register
 @hook TARGET_FNTYPE_ABI
 
+@hook TARGET_INSN_CALLEE_ABI
+
 @cindex call-used register
 @cindex call-clobbered register
 @cindex call-saved register
 @hook TARGET_HARD_REGNO_CALL_PART_CLOBBERED
 
-@hook TARGET_REMOVE_EXTRA_CALL_PRESERVED_REGS
-
 @hook TARGET_RETURN_CALL_WITH_MAX_CLOBBERS
 
 @hook TARGET_GET_MULTILIB_ABI_NAME