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

1 files changed, 13 insertions, 14 deletions

diff --git a/gcc/target.def b/gcc/target.def
index 803c7a3..adf7a96 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -4952,6 +4952,19 @@ interoperability between several ABIs in the same translation unit.",
  const predefined_function_abi &, (const_tree type),
  NULL)
 
+DEFHOOK
+(insn_callee_abi,
+ "This hook returns a description of the ABI used by the target of\n\
+call instruction @var{insn}; see the definition of\n\
+@code{predefined_function_abi} for details of the ABI descriptor.\n\
+Only the global function @code{insn_callee_abi} should call this hook\n\
+directly.\n\
+\n\
+Targets only need to define this hook if they support\n\
+interoperability between several ABIs in the same translation unit.",
+ const predefined_function_abi &, (const rtx_insn *insn),
+ NULL)
+
 /* ??? Documenting this hook requires a GFDL license grant.  */
 DEFHOOK_UNDOC
 (internal_arg_pointer,
@@ -5834,20 +5847,6 @@ DEFHOOK
  const char *, (void),
  hook_constcharptr_void_null)
 
-DEFHOOK
-(remove_extra_call_preserved_regs,
- "This hook removes registers from the set of call-clobbered registers\n\
- in @var{used_regs} if, contrary to the default rules, something guarantees\n\
- that @samp{insn} preserves those registers.  For example, some targets\n\
- support variant ABIs in which functions preserve more registers than\n\
- normal functions would.  Removing those extra registers from @var{used_regs}\n\
- can lead to better register allocation.\n\
- \n\
- The default implementation does nothing, which is always safe.\n\
- Defining the hook is purely an optimization.",
- void, (rtx_insn *insn, HARD_REG_SET *used_regs),
- default_remove_extra_call_preserved_regs)
-
 /* Return the smallest number of different values for which it is best to
    use a jump-table instead of a tree of conditional branches.  */
 DEFHOOK