This implements the aforementioned AI in all versions of the language since it is classified as a Binding Interpretation. The main visible effects are to turn errors given for the Pack aspect/pragma into mere warnings and to give new errors for representation clauses that do not abide by the alignment of some by-reference types, typically record types that are either volatile or contain a volatile subcomponent.
Tested on x86_64-pc-linux-gnu, committed on trunk
2019-12-16 Eric Botcazou <ebotca...@adacore.com>
gcc/ada/
* gcc-interface/decl.c (gnat_to_gnu_entity): Adjust calls to
validate_size.
(gnat_to_gnu_component_type): Likewise.
(gnat_to_gnu_field): Likewise and pass string for error messages.
(components_need_strict_alignment): Remove test on Is_Aliased and
add test for the independence of the component.
(validate_size): Add S1 and S2 string parameters and use them to
give better error messages for fields. Tweak a couple of messages.
* einfo.ads (Has_Independent_Components): Document more cases.
(Is_Independent): Likewise.
(Strict_Alignment): Document new semantics.
* exp_ch9.adb (Install_Private_Data_Declarations): Also set the
Is_Independent flag along with Is_Aliased on the renaming
entity.
* freeze.adb (Size_Known): Remove always-false test and add test
for the strict-alignment on the record type. Remove redundant
tests and add test for the strict-alignment on the component
type.
(Check_Strict_Alignment): Set the flag if the type is by-ref and
remove now redundant conditions. Set the flag on an array type
if it has aliased components. In the record type case, do not
set type for C_Pass_By_Copy convention.
(Freeze_Array_Type): Move code checking for conflicts between
representation aspects and clauses to before specific handling
of packed array types. Give a warnind instead of an error for a
conflict with pragma Pack. Do not test Has_Pragma_Pack for the
specific handling of packed array types.
(Freeze_Record_Type): Move error checking of representation
clause to...
(Freeze_Entity): ...here after Check_Strict_Alignment is called.
* sem_aggr.adb (Array_Aggr_Subtype): Also set the Is_Independent
flag along with Is_Aliased on the Itype.
* sem_ch13.adb (Check_Record_Representation_Clause): Do not set
the RM size for a strict-alignment type.
* sem_ch3.adb (Add_Interface_Tag_Components): Also set the
Is_Independent flag along with Is_Aliased on the tag.
(Add_Interface_Tag_Components): Likewise on the offset.
(Analyze_Component_Declaration): Likewise on the component.
(Analyze_Object_Declaration): Likewise on the object.
(Constrain_Array): Likewise on the array.
(Record_Type_Declaration: Likewise on the tag.
(Array_Type_Declaration): Also set the
Has_Independent_Components flag along with
Has_Aliased_Components on the array.
(Copy_Array_Base_Type_Attributes): Copy
Has_Independent_Components.
(Copy_Array_Subtype_Attributes): Copy Is_Atomic, Is_Independent
and Is_Volatile_Full_Access.
(Analyze_Iterator_Specification): Set Is_Independent on the loop
variable according to Independent_Components on the array.
* sem_ch5.adb: Likewise.
* sem_ch6.adb (Process_Formals): Also set the Is_Independent
flag along with Is_Aliased on the formal.
gcc/testsuite/
* gnat.dg/specs/clause_on_volatile.ads,
gnat.dg/specs/size_clause3.ads: Update expected diagnostics.
patch.diff.gz
Description: application/gzip
