Tracking issue: VHDL-2019 support

[Xiretza]

Just like VHDL-2008, VHDL-2019 brings a lot of new features to the language. While some of them are quite out there and probably hard to implement, there are also a few small quality-of-life improvements.

This issue will serve both as a place for discussion about the implementation of VHDL-2019 features in general, as well as to track the implementation of all the Language Changes.

General

• Add --std=19, update documentation accordingly:
  • Add --std=19 command line option #1981
• Add VHDL-2019 standard libraries from https://gitlab.com/IEEE-P1076/packages/-/tree/1076-2019

List of language changes

• LCS-2016-001 "Partially Connected Vectors on Port Map"
• LCS-2016-002 "Allow access and protected type parameters on function interfaces":
  • vhdl-sem_decls: allow out/inout parameters to impure function in VHDL-2019 #1983
• LCS-2016-004 "Allow Protected Type Method Parameters to be Access Types, Protected Types (functions), and File Types":
  • vhdl-sem_types: allow methods to return file and protected types in VHDL-2019 #1984
• LCS-2016-006a "File IO / Textio updates"
• LCS-2016-006c "File IO / Directory I/O"
• LCS-2016-006e "Allow access to system environment variables (baseline)"
• LCS-2016-006f "Expose standard conditional analysis identifiers"
• LCS-2016-007 "Sequential Declaration Regions"
• LCS-2016-011 "Date/Time functions"
• LCS-2016-012 "'IMAGE and TO_STRING for composite types"
• LCS-2016-014 "Composites of Protected Types"
• LCS-2016-014a "Pointers to Composites of Protected Types":
  • vhdl-sem_types: allow file and protected type access types in VHDL-2019 #1985
• LCS-2016-015 "Report Calling Path"
• LCS-2016-015a "ReportCallingPath - Current File and Line by function"
• LCS-2016-016 "Anonymous Types"
• LCS-2016-018 "Attributes for Enumerated Types"
• LCS-2016-018a "New attributes - 'index"
• LCS-2016-018d "New attributes - 'designated_type"
• LCS-2016-019 "Inferring Constraints from Initial Values for Signals and Variables"
• LCS-2016-023 "Relax Library Requirement on Configurations"
• LCS-2016-026c "LongIntegers"
  • 64 bit integer support #950
• LCS-2016-030 "Garbage Collection"
• LCS-2016-032 "PATH_NAME and Shared Variables and Subprograms"
• LCS-2016-033 "Composition with Protected Types"
• LCS-2016-034 "Protected Types with Generic Clause"
• LCS-2016-036a "Allow for conditional expressions in a declaration (baseline)"
• LCS-2016-041 "Record Introspection / Type Reflection"
• LCS-2016-043 "Attributes for PSL"
• LCS-2016-045a "Interface - defines new mode view construct for composite interface objects"
• LCS-2016-045c "Interface - 'CONVERSE for a mode view"
• LCS-2016-047 "Protected Type: Shared Variables On Entity Interface"
• LCS-2016-049 "Map Generics On Subprogram Call"
• LCS-2016-050 "API for Assert"
• LCS-2016-055a "Syntax regularization - component declarations"
• LCS-2016-059 "Array Type Generics"
• LCS-2016-059a "Allow ordering on any scalar array - related to Array Type Generics"
• LCS-2016-061 "Conditional compilation"
• LCS-2016-071a "Extra optional semicolon at the end of interface_list"
• LCS-2016-072b "Function Knows Return Vector Size"
• LCS-2016-075 "Closely related record types"
• LCS-2016-082 "Syntax regularization: empty records"
• LCS-2016-086 "All Interface Lists Can Be Ordered"
• LCS-2016-094a "Conditional Return Statement"
• LCS-2016-099 "Extended Ranges"

[Xiretza]

To get the ball rolling, the first thing should probably be to add a --std=19 option. @tgingold, if it's ok to treat Vhdl_19 as equivalent to Vhdl_08 to begin with, I can add that - but I can't check every place where Vhdl_Std is used for correctness, especially since I don't actually have a 2019 LRM or an accurate redline.

[tgingold]

Yes sure. There are other simple changes that could be done, like adding the new reserved identifier (keywords).

[Xiretza]

FYI, building the 2019 std library fails with these errors:

../../src/std/v19/env.vhdl:213:28:error: variable interface parameter are not allowed for a function (use a constant)
  impure function DIR_OPEN(Dir : out DIRECTORY; Path : in STRING) return DIR_OPEN_STATUS;
                           ^
../../src/std/v19/env.vhdl:213:28:error: mode of a function parameter cannot be inout or out
  impure function DIR_OPEN(Dir : out DIRECTORY; Path : in STRING) return DIR_OPEN_STATUS;
                           ^
../../src/std/v19/env.vhdl:214:29:error: type of constant interface "dir" cannot be record type "directory"
  procedure       DIR_CLOSE(Dir : in DIRECTORY);
                            ^
../../src/std/v19/env.vhdl:214:29:error: (record type "directory" has an access subelement)
  procedure       DIR_CLOSE(Dir : in DIRECTORY);
                            ^
../../src/std/v19/env.vhdl:244:30:error: type of constant interface "call_path" cannot be record type "call_path_element"
  impure function TO_STRING (call_path : CALL_PATH_ELEMENT ) return STRING;
                             ^
../../src/std/v19/env.vhdl:244:30:error: (record type "call_path_element" has an access subelement)
  impure function TO_STRING (call_path : CALL_PATH_ELEMENT ) return STRING;
                             ^
../../src/std/v19/env.vhdl:249:30:error: type of constant interface "call_path" cannot be array type "call_path_vector"
  impure function TO_STRING (call_path : CALL_PATH_VECTOR; Separator : STRING := "" & LF ) return STRING;
                             ^
../../src/std/v19/env.vhdl:249:30:error: (array type "call_path_vector" has an access subelement)
  impure function TO_STRING (call_path : CALL_PATH_VECTOR; Separator : STRING := "" & LF ) return STRING;
                             ^
../../src/std/v19/env.vhdl:255:30:error: type of constant interface "call_path" cannot be access type "call_path_vector_ptr"
  impure function TO_STRING (call_path : CALL_PATH_VECTOR_PTR; Separator : STRING := "" & LF ) return STRING;
                             ^

I'm not sure about the first one; the others are solved by LCS-2016-002.

[tgingold]

I think these are low hanging fruits, at least for the analyzer.

[JimLewis]

There are 2019 code examples at https://gitlab.com/synthworks/VHDL_2019. These are the ones I wrote for the presentations I did with Aldec.

LCS-2016-002 will help with some additional data structures I have planned.
LCS-2016-061 will allow library developers to put in work arounds for features being missing - such as conditionally include extra libraries.

[Paebbels]

@tgingold is LCS-2016-071a solved by 3160b44?

[tgingold]

Yes.

[Paebbels]

I checked the checkbox above. Is there anything else that could be checked? E.g. new packages?

[tgingold]

Not yet.

[stfarley]

Just wondering if there was any luck getting the standard libraries to compile.

[JimLewis]

These would also be exciting items to have:
LCS-2016-015 "Report Calling Path"
LCS-2016-015a "ReportCallingPath - Current File and Line by function"

[tgingold]

Understood!