This is the bulk of the implementation of pragma Volatile_Full_Access. It is
piggybacked on the existing support for atomic accesses in gigi and generates
the load-modify-store sequences when need be.
Tested on x86_64-suse-linux, applied on the mainline.
2015-05-25 Eric Botcazou <ebotca...@adacore.com>
* gcc-interface/gigi.h (build_atomic_load): Adjust prototype.
(build_atomic_store): Likewise.
(build_load_modify_store): Declare.
(VECTOR_TYPE_P): Delete.
* gcc-interface/decl.c (gnat_to_gnu_entity): Replace Is_Atomic with
Is_Atomic_Or_VFA throughout.
<E_Array_Type>: Build a variant of the XUA type instead of forcing
TYPE_VOLATILE on it.
<E_Array_Subtype>: Use the main variant of the base type.
Do not force TYPE_VOLATILE on the type being built.
<E_Record_Type>: Likewise.
<E_Array_Subtype>: Likewise.
<E_Subprogram_Type>: Rename local variable.
Add Atomic qualifier in conjunction with Volatile on types if needed.
Force BLKmode for by-ref types only at the end of the processing.
Change qualifiers only after changing the mode of the type. Set
TYPE_UNIVERSAL_ALIASING_P on the type directly.
(check_ok_for_atomic_type): Issue specific error message for VFA.
(gnat_to_gnu_component_type): Replace Is_Atomic with
Is_Atomic_Or_VFA throughout.
* gcc-interface/misc.c (gnat_get_alias_set): Test
TYPE_UNIVERSAL_ALIASING_P on the type directly.
* gcc-interface/trans.c (lvalue_required_p): Replace Is_Atomic with
Is_Atomic_Or_VFA throughout. Add missing guard.
(node_is_atomic): New predicate.
(node_has_volatile_full_access): Likewise.
(gnat_strip_type_conversion): New function.
(outer_atomic_access_required_p): New predicate.
(atomic_sync_required_p): Rename into...
(atomic_access_required_p): ...this. Add SYNC parameter, scan the
parent node first and then look for the atomic setting. Add support
for Volatile_Full_Access.
(Call_to_gnu): Add atomic_access and outer_atomic_access parameters
and adjusts calls to above functions. Use load-modify-store sequence
for updates of In/Out and Out parameters if required, as well as for
moving the result to the target if required. Add couple of missing
guards.
(gnat_to_gnu): Adjust calls to above functions.
<N_Object_Renaming_Declaration>: If the renamed object has side-effects
evaluate only its address.
<N_Assignment_Statement>: Adjust call to Call_to_gnu. Use load-modify
store sequence if required.
<N_Function_Call>: Adjust call to Call_to_gnu.
(extract_values): Adjust comment.
* gcc-interface/utils2.c (build_atomic_load): Add SYNC parameter and
use relaxed memory model if it is not set.
(build_atomic_store): Likewise.
(call_is_atomic_load): New predicate.
(build_load_modify_store): New function.
(build_binary_op) <MODIFY_EXPR>: Accept SAVE_EXPR on the LHS.
(gnat_stabilize_reference) <CALL_EXPR>: Deal with atomic loads.
2015-05-25 Eric Botcazou <ebotca...@adacore.com>
* gnat.dg/vfa1_1.adb: New test.
* gnat.dg/vfa1_2.adb: Likewise.
* gnat.dg/vfa1_3.adb: Likewise.
* gnat.dg/vfa1_4.adb: Likewise.
* gnat.dg/vfa1_pkg.ads: New helper.
--
Eric Botcazou
