2020-06-16 Javier Miranda <miranda@adacore.com>
gcc/ada/
* restrict.adb (Global_No_Tasking): Adding
Targparm.Restrictions_On_Target Fixes regressions with zfp.
2020-06-16 Ed Schonberg <schonberg@adacore.com>
gcc/ada/
* freeze.adb: (Freeze_Expression, In_Expanded_Body): Treat the
generated body of an expression function like other bodies
generated during expansion (e.g. stream subprograms) so that
those bodies are not treated as freezing points. Handle properly
other global references in such completions.
2020-06-16 Eric Botcazou <ebotcazou@adacore.com>
gcc/ada/
* sem_ch12.adb (Validate_Derived_Type_Instance): Reword error
message for 12.5.1(8) subclause and add secondary message if
the incompatibility comes from the predicates.
* sem_ch3.adb (Check_Constraining_Discriminant): New procedure
to give the error required by the 3.7(15) subclause. Mention
"statically" in the error message and add secondary message
if the incompatibility comes from the predicates.
(Build_Derived_Concurrent_Type): Call it when a new discriminant
constrains an old one.
(Build_Derived_Record_Type): Likewise.
* sem_eval.ads (Predicates_Compatible): Declare.
* sem_eval.adb (Predicates_Compatible): New function to implement
the compatibility of predicates specified by the 4.9.1 clause.
(Subtypes_Statically_Compatible): Call it.
This adds an assert to enforce_access to verify that we don't defer
access checks of dependent decls -- we should instead be rechecking the
access of such a decl after tsubst'ing into the user of the decl.
gcc/cp/ChangeLog:
* pt.c (perform_instantiation_time_access_checks): No need to
tsubst into decl.
* semantics.c (enforce_access): Verify that decl is not
dependent.
The previous patch mostly avoided making any changes that had no
functional impact, such as adjusting now-outdated comments and
performing renamings. Such changes have been consolidated to this
followup patch for easier review.
The main change here is that we now reuse struct deferred_access_check
as the element type of the vector TI_TYPEDEFS_NEEDING_ACCESS_CHECKING
(now renamed to TI_DEFERRED_ACCESS_CHECKS, since it may contain any kind
of access check).
gcc/cp/ChangeLog:
PR c++/41437
PR c++/47346
* cp-tree.h (qualified_typedef_usage_s): Delete.
(qualified_typedef_usage_t): Delete.
(deferred_access_check): Move up in file.
(tree_template_info::typedefs_needing_access_checking): Delete.
(tree_template_info::deferred_access_checks): New field.
(TI_TYPEDEFS_NEEDING_ACCESS_CHECKING): Rename to ...
(TI_DEFERRED_ACCESS_CHECKS): ... this, and adjust accordingly.
* pt.c (perform_typedefs_access_check): Rename to ...
(perform_instantiation_time_access_checks): ... this, and adjust
accordingly. Remove unnecessary tree tests.
(instantiate_class_template_1): Adjust accordingly.
(instantiate_decl): Likewise.
* semantics.c (enforce_access): Likewise.
This patch generalizes our existing functionality for deferring access
checking of typedefs when parsing a function or class template to now
defer all kinds of access checks until template instantiation time,
including member function and member object accesses.
Since all access checks eventually go through enforce_access, the main
component of this patch is new handling inside enforce_access to defer
the current access check if we're inside a template. The bulk of the
rest of the patch consists of removing now-unneeded code pertaining to
suppressing access checks inside templates or pertaining to
typedef-specific access handling. Renamings and other changes with no
functional impact have been split off into the followup patch.
gcc/cp/ChangeLog:
PR c++/41437
PR c++/47346
* call.c (enforce_access): Move to semantics.c.
* cp-tree.h (enforce_access): Delete.
(get_types_needing_access_check): Delete.
(add_typedef_to_current_template_for_access_check): Delete.
* decl.c (make_typename_type): Adjust accordingly. Use
check_accessibility_of_qualified_id instead of directly using
perform_or_defer_access_check.
* parser.c (cp_parser_template_declaration_after_parameters):
Don't push a dk_no_check access state when parsing a template.
* pt.c (get_types_needing_access_check): Delete.
(append_type_to_template_for_access_check_1): Delete.
(perform_typedefs_access_check): Adjust. If type_decl is a
FIELD_DECL, also check its DECL_CONTEXT for dependence. Use
tsubst_copy instead of tsubst to substitute into type_decl so
that we substitute into the DECL_CONTEXT of a FIELD_DECL.
(append_type_to_template_for_access_check): Delete.
* search.c (accessible_p): Remove the processing_template_decl
early exit.
* semantics.c (enforce_access): Moved from call.c. If we're
parsing a template and the access check failed, add the check to
TI_TYPEDEFS_NEEDING_ACCESS_CHECKING.
(perform_or_defer_access_check): Adjust comment.
(add_typedef_to_current_template_for_access_check): Delete.
(check_accessibility_of_qualified_id): Adjust accordingly.
Exit early if the scope is dependent.
gcc/testsuite/ChangeLog:
PR c++/41437
PR c++/47346
* g++.dg/cpp2a/concepts-using2.C: Adjust.
* g++.dg/lto/20081219_1.C: Adjust.
* g++.dg/lto/20091002-1_0.C: Adjust.
* g++.dg/lto/pr65475c_0.C: Adjust.
* g++.dg/opt/dump1.C: Adjust.
* g++.dg/other/pr53574.C: Adjust.
* g++.dg/template/access30.C: New test.
* g++.dg/template/access31.C: New test.
* g++.dg/wrappers/wrapper-around-type-pack-expansion.C: Adjust.
libstdc++-v3/ChangeLog:
PR libstdc++/94003
* testsuite/20_util/is_constructible/94003.cc: New test.
The following avoids calling set_mem_attributes on the
DECL_INITIAL of a CONST_DECL which seems pointless since there
cannot be a sensible MEM_EXPR derived from that. We're overwriting
both other possibly useful info, alias-set and alignment immediately
so the following patch simply removes the call instead of making
the function deal with even more (unexpected) trees that are not
memory accesses.
2020-06-16 Richard Biener <rguenther@suse.de>
PR middle-end/95690
* varasm.c (build_constant_desc): Remove set_mem_attributes call.
* gfortran.dg/pr95690.f90: New testcase.
- riscv_gpr_save_operation_p might try to match parallel on other
patterns like inline asm pattern, and then it might trigger ther
assertion checking there, so we could trun it into a early exit check.
gcc/ChangeLog:
PR target/95683
* config/riscv/riscv.c (riscv_gpr_save_operation_p): Remove
assertion and turn it into a early exit check.
gcc/testsuite/ChangeLog
PR target/95683
* gcc.target/riscv/pr95683.c: New.
2020-06-09 Nicolas Bértolo <nicolasbertolo@gmail.com>
* Make-lang.in: Always define version, minor and release
numbers. Create the Windows shared library as
libgccjit-$(LIBGCCJIT_VERSION_NUM).dll.
gimplify_modify_expr_rhs has an optimization whereby the assignment to
an aggregate variable from a read-only object with a DECL_INITIAL is
optimized into the direct assignment of the DECL_INITIAL, provided that
no temporary is created in the process.
The optimization is blocked if the read-only object is volatile, which
is OK as per the semantics of volatile, but also if the target variable
is volatile, on the grounds that the modified assignment might end up
being done on a per field basis, which is also OK. But this latter
restriction is enforced a priori and there are cases where the modified
assignment would be OK, for example if there is only one field or the
DECL_INITIAL is equivalent to the empty CONSTRUCTOR, i.e. all zeros.
So, in the latter case, the patch changes gimplify_modify_expr_rhs to ask
gimplify_init_constructor whether the assignment would be done as a block,
which is easy because gimplify_init_constructor knows that it must create
a temporary if the LHS is volatile and this would not be the case, so it's
just a matter of completing the NOTIFY_TEMP_CREATION mechanism.
gcc/ChangeLog
* gimplify.c (gimplify_init_constructor) <AGGREGATE_TYPE>: Declare
new ENSURE_SINGLE_ACCESS constant and move variables down. If it is
true and all elements are zero, then always clear. Return GS_ERROR
if a temporary would be created for it and NOTIFY_TEMP_CREATION set.
(gimplify_modify_expr_rhs) <VAR_DECL>: If the target is volatile but
the type is aggregate non-addressable, ask gimplify_init_constructor
whether it can generate a single access to the target.
gcc/testsuite/ChangeLog
* gnat.dg/aggr30.ads, gnat.dg/aggr30.adb: New test.
This fixes an issue with reverse storage order in SRA, which is caught
by the built-in verifier in verify_sra_access_forest. The problem is
that propagate_subaccesses_from_rhs changes the type of an access
from aggregate to scalar and, as discussed elsewhere, this must be
done with extra care in the presence of reverse storage order.
gcc/ChangeLog
* tree-sra.c (propagate_subaccesses_from_rhs): When a non-scalar
access on the LHS is replaced with a scalar access, propagate the
TYPE_REVERSE_STORAGE_ORDER flag of the type of the original access.
gcc/testsuite/ChangeLog
* gnat.dg/opt85.ads, gnat.dg/opt85.adb: New test.
Although not required by SD-6 or the C++20 draft, we define the macro
__cpp_lib_constexpr_char_traits to indicate support for P0432R1. This
updates the value in C++20 mode for the P1032R1 changes to char_traits.
* include/bits/char_traits.h (__cpp_lib_constexpr_char_traits):
Update value for C++20.
* include/std/version (__cpp_lib_constexpr_char_traits): Likewise.
* testsuite/21_strings/char_traits/requirements/constexpr_functions_c++17.cc:
Update expected value.
* testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc:
Likewise.
Upon constexpr evaluation, char_traits move uses copy_backward, but its
last argument should be to the range end rather than its beginning.
2020-06-12 Paul Keir <paul.keir@uws.ac.uk>
* include/bits/char_traits.h (char_traits::move): constexpr move with
overlap was using copy_backward incorrectly.
* testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc:
New test.
Remove TARGET_THREADPTR reference from TARGET_HAVE_TLS to avoid
static data initialization dependency on xtensa core configuration.
2020-06-15 Max Filippov <jcmvbkbc@gmail.com>
gcc/
* config/xtensa/xtensa.c (TARGET_HAVE_TLS): Remove
TARGET_THREADPTR reference.
(xtensa_tls_symbol_p, xtensa_tls_referenced_p): Use
targetm.have_tls instead of TARGET_HAVE_TLS.
(xtensa_option_override): Set targetm.have_tls to false in
configurations without THREADPTR.
Remove ABI reference from the ELIMINABLE_REGS to avoid static data
initialization dependency on xtensa core configuration.
2020-06-15 Max Filippov <jcmvbkbc@gmail.com>
gcc/
* config/xtensa/xtensa.c (xtensa_can_eliminate): New function.
(TARGET_CAN_ELIMINATE): New macro.
* config/xtensa/xtensa.h
(XTENSA_WINDOWED_HARD_FRAME_POINTER_REGNUM)
(XTENSA_CALL0_HARD_FRAME_POINTER_REGNUM): New macros.
(HARD_FRAME_POINTER_REGNUM): Define using
XTENSA_*_HARD_FRAME_POINTER_REGNUM.
(ELIMINABLE_REGS): Replace lines with HARD_FRAME_POINTER_REGNUM
by lines with XTENSA_WINDOWED_HARD_FRAME_POINTER_REGNUM and
XTENSA_CALL0_HARD_FRAME_POINTER_REGNUM.
since Alexandre's revamp of dump files handling in
r11-627-g1dedc12d186, BRIG FE has been receiving slightly different
-dumpbase (e.g. smoke_test.brig instead of smoke_test.hsail.brig when
compiling file smoke_test.hsail.brig) and the testsuite then could not
find the generated dump files it wanted to scan. I have not really
looked into why that changed, the easiest fix seems to me to remove
the hsail part already when generating the binary brig file from the
textual HSAIL representation.
gcc/testsuite/ChangeLog:
2020-06-09 Martin Jambor <mjambor@suse.cz>
* lib/brig.exp (brig_target_compile): Strip hsail extension when
gnerating the name of the binary brig file.
Minor code refactorings in tree-vect-data-refs.c and tree-vect-loop.c.
Use LOOP_VINFO_DATAREFS and LOOP_VINFO_DDRS when possible and rename
several parameters to make code more consistent.
2020-06-13 Felix Yang <felix.yang@huawei.com>
gcc/
* tree-vect-data-refs.c (vect_verify_datarefs_alignment): Rename
parameter to loop_vinfo and update uses. Use LOOP_VINFO_DATAREFS
when possible.
(vect_analyze_data_refs_alignment): Likewise, and use LOOP_VINFO_DDRS
when possible.
* tree-vect-loop.c (vect_dissolve_slp_only_groups): Use
LOOP_VINFO_DATAREFS when possible.
(update_epilogue_loop_vinfo): Likewise.
2020-06-15 Arnaud Charlet <charlet@adacore.com>
gcc/ada/
* sem_ch8.adb (Premature_Usage): Add support for subtype
references and replace set of if-then-else by a case statement.
2020-06-15 Piotr Trojanek <trojanek@adacore.com>
gcc/ada/
* sem_prag.adb (Analyze_Depends_In_Decl_Part,
Analyze_Global_In_Decl_Part): Bring back task discriminants for
analysis of the Global/Depends contracts; add comments.
2020-06-15 Eric Botcazou <ebotcazou@adacore.com>
gcc/ada/
* einfo.ads (Return_Applies_To): Document special usage for E_Block.
* einfo.adb (Write_Field8_Name): Write it for E_Block too.
* exp_ch4.adb (Expand_N_Type_Conversion): Remove implementation of
the check prescribed by AI05-0073.
* exp_ch6.adb (Apply_CW_Accessibility_Check): New procedure to apply
the check prescribed by AI95-344 extracted from...
(Expand_N_Extended_Return_Statement): Apply the check prescribed by
AI95-344 to the expression, if present. Suppress only access checks
when analyzing the rewritten result.
(Expand_Simple_Function_Return): ...here. Rename local variable.
Call Apply_CW_Accessibility_Check to apply the check prescribed by
AI95-344, but do not do it for the simple return statement generated
by the expansion of an extended return statement. Apply the check
prescribed by AI05-0073 to all functions returning anonymous access
type designating a specific tagged type, but not if the expression
was null or tag checks are suppressed for the type, and use Not In
operator rather than comparing the tags explicitly.
* sem.adb (Analyze): Handle all Suppress values.
* sem_ch6.adb (Analyze_Function_Return): Do not explicitly apply
predicate checks in the case of an extended return statement.
Do not apply an implicit conversion to the anonymous access result
type in the case of the simple return statement generated by the
expansion of an extended return statement.
(New_Overloaded_Entity): Small comment tweak.
* treepr.adb (Print_Node): Fix typo in flag string.
2020-06-15 Bob Duff <duff@adacore.com>
gcc/ada/
* exp_put_image.ads, exp_put_image.adb
(Image_Should_Call_Put_Image): New function to determine whether
the call to Put_Image should be generated.
(Build_Image_Call): New procedure to generate the call to
Put_Image.
* exp_imgv.adb (Expand_Image_Attribute): Use underlying types to
bypass privacy (only in Ada 2020). If
Image_Should_Call_Put_Image is True (which happens only in Ada
2020), then call Build_Image_Call.
* rtsfind.ads, rtsfind.adb: Add the necessary declarations in
Ada.Strings.Text_Output.Buffers.
* sem_attr.adb (Check_Image_Type): Enable the Ada 2020 case.
* libgnat/a-stoufo.ads, libgnat/a-stoufo.adb: Use the less
restrictive type that allows newline characters.
2020-06-15 Piotr Trojanek <trojanek@adacore.com>
gcc/ada/
* sem_ch13.adb (Analyze_Aspect_Relaxed_Initialization): Fix
dealing with scopes on subprogram bodies that act as specs.
* sem_util.adb (Has_Relaxed_Initialization): Fix trivial
mistake.
2020-06-15 Javier Miranda <miranda@adacore.com>
gcc/ada/
* restrict.ads (Set_Global_No_Tasking, Global_No_Tasking): New
subprograms.
* restrict.adb (Set_Global_No_Tasking, Global_No_Tasking): New
subprograms.
* sem_ch3.adb (Access_Definition): Do not skip building masters
since they may be required for BIP calls.
(Analyze_Subtype_Declaration): Propagate attribute
Is_Limited_Record in class-wide subtypes and subtypes with
cloned subtype attribute; propagate attribute
Is_Limited_Interface.
* sem_ch6.adb (Check_Anonymous_Return): Do not skip building
masters since they may be required for BIP calls. Use
Build_Master_Declaration to declare the _master variable.
(Create_Extra_Formals): Add decoration of Has_Master_Entity when
the _master formal is added.
* exp_ch3.adb (Init_Formals): Adding formal to decorate it with
attribute Has_Master_Entity when the _master formal is added.
(Build_Master): Do not skip building masters since they may be
required for BIP calls.
(Expand_N_Object_Declaration): Ensure activation chain and
master entity for objects initialized with BIP function calls.
* sem_prag.adb (Process_Restrictions_Or_Restriction_Warnings):
Adding support to detect and save restriction No_Tasking when
set in the run-time package System or in a global configuration
pragmas file.
* sem_util.adb (Current_Entity_In_Scope): Overload this
subprogram to allow searching for an entity by its Name.
* sem_util.ads (Current_Entity_In_Scope): Update comment.
* exp_ch4.adb (Expand_N_Allocator): Do not skip building masters
since they may be required for BIP calls.
* exp_ch6.ads (Might_Have_Tasks): New subprogram.
* exp_ch6.adb (Make_Build_In_Place_Call_In_Allocator): Add
support for BIP calls returning objects that may have tasks.
(Make_Build_In_Place_Call_In_Allocator): Build the activation
chain if the result might have tasks.
(Make_Build_In_Place_Iface_Call_In_Allocator): Build the class
wide master for the result type.
(Might_Have_Tasks): New subprogram.
(Needs_BIP_Task_Actuals): Returns False when restriction
No_Tasking is globally set.
* exp_ch9.ads (Build_Master_Declaration): New subprogram.
* exp_ch9.adb (Build_Activation_Chain_Entity): No action
performed when restriction No_Tasking is globally set.
(Build_Class_Wide_Master): No action performed when restriction
No_Tasking is globally set; use Build_Master_Declaration to
declare the _master variable.
(Build_Master_Declaration): New subprogram.
(Build_Master_Entity): No action performed when restriction
No_Tasking is globally set; added support to handle transient
scopes and _finalizer routines.
(Build_Master_Renaming): No action performed when restriction
No_Tasking is globally set.
(Build_Task_Activation_Call): Skip generating the call when
the chain is an ignored ghost entity.
(Find_Master_Scope): Generalize the code that detects transient
scopes with master entity.
* einfo.ads (Has_Nested_Subprogram): Minor comment reformatting.
2020-06-15 Gary Dismukes <dismukes@adacore.com>
gcc/ada/
* exp_ch6.adb (Add_Call_By_Copy_Code): In the case of a view
conversion passed to a scalar out-mode parameter where the
formal has Default_Value set, declare the copy temp with the
base type of the formal's subtype and initialize the copy temp
with the actual's value.
2020-06-15 Justin Squirek <squirek@adacore.com>
gcc/ada/
* exp_ch4.adb (Expand_N_Case_Expression): Set default value for
Target to silence potential warnings.
(Expand_N_If_Expression): Add calculation to check when the if
expression is used directly in the context of an actual of an
anonymous access type and add a special path to force expansion
of the if expression in this case.
* exp_ch6.adb (Expand_Branch): Generate an assignment to the
level temporary for a given branch.
(Expand_Call_Helper): Add expansion to allow for creating a
temporary to store associated accessiblity levels on each branch
of the conditional expression. Also perform expansion of
function calls into expressions with actions, and fixup
references to N with Call_Node.
(Insert_Level_Assign): Move through nested conditional
expressions to each branch.
* sem_util.ads, sem_util.adb (Is_Anonymous_Access_Actual): Added
to detect when to force expansion of if expressions.
2020-06-15 Piotr Trojanek <trojanek@adacore.com>
gcc/ada/
* sem_prag.adb (Analyze_Depends_In_Decl_Part,
Analyze_Global_In_Decl_Part): Do not install task discriminants
for analysis of the Global/Depends contracts.
2020-06-15 Piotr Trojanek <trojanek@adacore.com>
gcc/ada/
* contracts.adb (Analyze_Object_Contract): Do not expect
Global/Depends on single protected units.
2020-06-15 Justin Squirek <squirek@adacore.com>
gcc/ada/
* sem_res.adb (Valid_Conversion): Add missing condition to
trigger proper static accessiblity failiures when the target
type is an anonymous access.
2020-06-15 Piotr Trojanek <trojanek@adacore.com>
gcc/ada/
* exp_ch6.adb, sem_util.adb: Remove excessive parents,
especially since they don't make the code any easier to read.
2020-06-15 Piotr Trojanek <trojanek@adacore.com>
gcc/ada/
* aspects.ads (Aspect_Id): Add Aspect_Relaxed_Initialization.
(Implementation_Defined_Aspect): Add new aspect.
(Aspect_Argument): Add new aspect with Optional_Expression
argument.
(Is_Representation_Aspect): Add new aspect as a
non-representation one.
(Aspect_Names): Add name for the new aspect.
(Aspect_Delay): Add new aspect as a non-delayed one.
* sem_ch3.adb: Minor reformatting.
* einfo.ads, einfo.adb (Is_Relaxed_Initialization_State): New
query; reuses existing code for querying abstract state options.
* exp_attr.adb (Expand_N_Attribute_Reference): For now ignore
attribute 'Initialized.
* sem_attr.adb (Analyze_Attribute_Old_Result): Allow attribute
'Result to be used in the aspect Relaxed_Initialization
expression.
(Analyze_Attribute): Analyze attribute 'Initialized; based on
existing code for attribute 'Valid_Scalars.
(Eval_Attribute): Do not expect attribute 'Initialized, just
like attribute 'Valid_Scalars is not expected.
* sem_ch13.adb (Analyze_Aspect_Relaxed_Initialization): New
routine.
(Analyze_Aspect_Specifications): Analyze new aspect in a
dedicated routine.
(Check_Aspect_At_Freeze_Point): Do not expect new aspect.
* sem_prag.adb (Analyze_Abstract_State): Support option
Relaxed_Initialization on abstract states.
* sem_util.ads, sem_util.adb (Has_Relaxed_Initialization): New
query for the GNATprove backend.
* snames.ads-tmpl (Snames): Add Name_Ids for the new aspect and
attribute; add an Attribute_Id for the new attribute.
2020-06-15 Bob Duff <duff@adacore.com>
gcc/ada/
* exp_put_image.adb, libgnat/s-putima.adb, libgnat/s-putima.ads,
rtsfind.ads: Enable Put_Image if Is_Access_Subprogram_Type (Typ).
Remove comment saying it's disabled in that case. Rename
Put_Image_Access_Prot to be Put_Image_Access_Prot_Subp to
clarify that we're talking about access-to-subprogram, not
access-to-protected-object.
2020-06-15 Bob Duff <duff@adacore.com>
gcc/ada/
* sem_attr.adb (Check_Image_Type): New procedure for checking
the type, depending on language version. Disable the Ada 2020
support until the corresponding expander work is done.
(Analyze_Image_Attribute): Call Check_Image_Type. Rearrange the
code to be simplier and more logical. When P_Type is modified,
modify P_Base_Type accordingly.
* sem_util.adb (Is_Object_Image): Do not return False if the
prefix is a type. X'Image should be considered an image of an
object iff X is an object (albeit illegal pre-2020 if
nonscalar).
2020-06-15 Bob Duff <duff@adacore.com>
gcc/ada/
* libgnat/s-putima.ads, libgnat/s-putima.adb
(Put_Image_Access_Subp, Put_Image_Access_Prot): New procedures
for printing access-to-subprogram objects. Remove an explicit
" ", because Put_Image includes the annoying leading blank.
* rtsfind.ads: Add new procedures in s-putima.
* exp_put_image.adb: Call new procedures as appropriate.
2020-06-15 Bob Duff <duff@adacore.com>
gcc/ada/
* exp_imgv.adb (Expand_Image_Attribute): Allow private types.
Put_Image generates Image for numeric types, and private types
whose full type is numeric. This requires the Conversion_OK flag
for integer and floating-point types. For fixed point, we need
the extra conversion.
* exp_put_image.adb (Build_Elementary_Put_Image_Call): Remove
special handling of real types.
(Enable_Put_Image): Enable for reals.
2020-06-15 Bob Duff <duff@adacore.com>
gcc/ada/
* exp_attr.adb (Put_Image): Use underlying type for strings.
Remove unchecked union processing.
* exp_put_image.adb (Tagged_Put_Image_Enabled): Use -gnatd_z to
enable default Put_Image for tagged types. This allows testing
that feature.
(Build_String_Put_Image_Call): Set Conversion_OK flag.
(Make_Component_List_Attributes): Remove unchecked union
processing.
(Enable_Put_Image): Disable for unchecked unions. Enable for
nonscalar types (which were mistakenly disabled in earlier
changes).
* debug.adb: Document -gnatd_z switch.
* libgnat/s-putima.adb (Put_Image_String, Put_Image_Wide_String,
Put_Image_Wide_Wide_String): Double double-quote characters.
Forget about special handling of control characters for now --
that's rare enough to not be a priority, and it's not clear what
the right thing to do is anyway.
* namet.adb: Minor: Improve debugger-friendliness.
* sinfo.ads: Minor: Add "???" comment.
