When generating TSS address finalization bodies for a tagged class-wide
subtype, GNAT climbs the parent chain looking for the first
"non-constrained" type. That type's underlying type's class-wide type is
used as a "designated" type for a dispatching TSS deep finalize call to the
designated class-wide type. In the case of a constrained subtype of an
unconstrained synchronized private extension, this ends up designating the
underlying type of that private extension. This means it targets the
class-wide type of the actual underlying concurrent type rather than the
corresponding record. Ultimately it ends up generating a call to the
corresponding record's deep finalizer, but with incompatible types
(concurrent_type'Class -> concurrent_typeV'Class). This causes compilation
to fail.

 

This patch adds extra logic to exp_ch7(Make_Finalize_Address_Stmts) to
identify such cases and ensure that the designated type is the corresponding
record type's class-wide type in that situation.

 

Patch file is attached.

 

--  Begin change log entry -

 

ada: TSS finalize address subprogram generation for constrained subtypes of
unconstrained synchronized private extensions should take care to designate
the corresponding record of the underlying concurrent type.

 

When generating TSS finalize address subprograms for class-wide types of
constrained root types, it follows the parent chain looking for the first
"non-constrained" type. It is possible that such a type is a private
extension with the "synchronized" keyword, in which case the underlying type
is a concurrent type. When that happens, the designated type of the finalize
address subprogram should be the corresponding record's class-wide-type.

 

Gcc/ada/

                * exp_ch3(Expand_Freeze_Class_Wide_Type): Expanded comments
explaining why TSS Finalize_Address is not generated for concurrent
class-wide types.

                * exp_ch7(Make_Finalize_Address_Stmts): Handle cases where
the underlying non-constrained parent type is a concurrent type, and adjust
the designated type to be the corresponding record's class-wide type.

 

--  End change log entry -

 

This patch was bootstrapped on x86_64-*-freebsd13.2. One new test cases was
added. Note that 4 gnat test cases fail currently on master and are
unrelated to this patch.

 

Check-ada output of this patch:

 

                                === acats tests ===

Running chapter a ...

Running chapter c2 ...

Running chapter c3 ...

Running chapter c4 ...

Running chapter c5 ...

Running chapter c6 ...

Running chapter c7 ...

Running chapter c8 ...

Running chapter c9 ...

Running chapter ca ...

Running chapter cb ...

Running chapter cc ...

Running chapter cd ...

Running chapter ce ...

Running chapter cxa ...

Running chapter cxb ...

Running chapter cxf ...

Running chapter cxg ...

Running chapter cxh ...

Running chapter cz ...

Running chapter d ...

Running chapter e ...

Running chapter l ...

                                === acats Summary ===

# of expected passes                       2328

# of unexpected failures                 0

 

Native configuration is x86_64-unknown-freebsd13.2

 

                                === gnat tests ===

 

Schedule of variations:

    unix

 

Running target unix

FAIL: gnat.dg/specs/alignment2.ads  (test for warnings, line 14)

FAIL: gnat.dg/specs/alignment2.ads  (test for warnings, line 20)

FAIL: gnat.dg/specs/alignment2.ads  (test for warnings, line 38)

FAIL: gnat.dg/specs/alignment2.ads  (test for warnings, line 42)

 

                                === gnat Summary ===

 

# of expected passes                       3401

# of unexpected failures                 4

# of expected failures                      23

# of unsupported tests                   10

gnatmake version 14.0.0 20230809 (experimental)

 

 

Richard Wai

ANNEXI-STRAYLINE