Re: Error when using EXPORT UNQUALIFIED in an FFI def. module

[Gaius Mulley]

Alice Osako <alicetrillianosako@gmail.com> writes:

> When working on the FFI definition file for stdio for M2PP:
>
> https://github.com/m2sf/m2pp/blob/master/src/posix/stdio.gm2.iso.def
>
> the code as currently written includes an extensive EXPORT UNQUALIFIED 
> statement for several of the constants, types, and procedures defined therein.
> According to Benjamin Kowarsch, this was originally done because - at the 
> time the code was written - a gm2 FFI definition file did not allow 
> unqualified
> imports without explicitly permitting it.
>
> However, with the current build of gm2, this causes a peculiar error message, 
> indicating a possible parsing error: 
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> make -f Makefile bfsys 
>
> /home/schol-r-lea/opt/bin/gm2 -g -fiso -freport-bug 
> -fdebug-function-line-numbers -Isrc/ -c src/imp/BasicFileSys.mod \
> -o obj/BasicFileSys.o
> src/stdio.def:20:1: warning: In definition module ‘stdio’: syntax warning, 
> ‘END’ missing 
>    20 | FROM SYSTEM IMPORT
>       | ^~~~
> src/stdio.def:20:13: warning: syntax warning, ‘.’ missing 
>    20 | FROM SYSTEM IMPORT
>       |             ^~~~~~
> src/stdio.def:3:27: error: module name at beginning ‘stdio’ does not match 
> the name at end ‘SYSTEM’
>     3 | DEFINITION MODULE FOR "C" stdio; (* GNU Modula-2 ISO version *)
>       |                           ^~~~~
> src/stdio.def:20:1: error: syntax error, found ‘FROM’
>    20 | FROM SYSTEM IMPORT
>       | ^~~~
> src/stdio.def:20:6: error: module name at end ‘SYSTEM’ does not match the 
> name at beginning ‘stdio’
>    20 | FROM SYSTEM IMPORT
>       |      ^~~~~~
> src/stdio.def:20:13: error: no scope active: syntax error, found ‘IMPORT’
>    20 | FROM SYSTEM IMPORT
>       |             ^~~~~~
> src/stdio.def:146:11: error: compilation failed
>   146 | END stdio.
>       |           ^
> make: *** [Makefile:93: bfsys] Error 1
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> It appears to cause the parser to treat the rest of the source file as 
> garbage. When the EXPORT statement is deleted, compilation proceeds normally.
>
> This appears to be a bug, though just what the correct behavior should be 
> here isn't clear to me - either the statement is redundant, and should be 
> removed
> anyway, or it is still necessary and should not raise an error, or else it is 
> an error and should be flagged as such. I am assuming that the EXPORT is 
> merely
> unneeded here; from what I was told, EXPORT should only normally be used in 
> nested modules, anyway, but should still be syntactically valid in outer
> modules (just ignored).
>
> Sorry to bring yet more things up here.

all valuable feedback thanks!

I set up the source dir via:

$ mkdir build
$ cd build
$ cp ../src/posix/stdio.gm2.pim.def stdio.def
$ cp ../src/Size.longint.def Size.def
$ cp ../src/imp/BasicFileSys.mod .
$ gm2 -g -I../src/ -fsources -c BasicFileSys.mod 
Compiling: BasicFileSys.mod
Pass 0: lexical analysis, parsing, modules and associated filenames
   Module SYSTEM               : 
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2cor/SYSTEM.def [m2cor]
   Module M2RTS                : 
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2pim/M2RTS.def [m2pim]
   Module RTExceptions         : 
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2pim/RTExceptions.def 
[m2pim]
   Module BasicFileSys         : ../src/BasicFileSys.def
   Module BasicFileSys         : BasicFileSys.mod
   Module COROUTINES           : 
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2pim/COROUTINES.def 
[m2pim] (for C)
   Module Size                 : ./Size.def
   Module FileSystem           : 
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2log/FileSystem.def 
[m2log]
   Module FIO                  : 
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2pim/FIO.def [m2pim]
   Module DynamicStrings       : 
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2pim/DynamicStrings.def 
[m2pim]
Pass 1: scopes, enumerated types, imports and exports
Pass 2: constants and types
Pass C: aggregate constants
Pass 3: quadruple generation
Pass 4: gcc tree generation
        symbols to gcc trees
        statements to gcc trees
terminate called after throwing an instance of 'unsigned int'
cc1gm2: internal compiler error: Aborted

and the error is the relop in the const expression as reported before.

I had to fix a couple of bugs in BasicFileSys.mod

$ diff -ruw ../src/imp/BasicFileSys/BasicFileSys.pim.mod BasicFileSys.mod 
--- ../src/imp/BasicFileSys/BasicFileSys.pim.mod        2024-03-31 
19:08:22.851442410 +0100
+++ BasicFileSys.mod    2024-04-03 02:24:20.015001955 +0100
@@ -22,7 +22,7 @@
      exist then we have to close it again. Bad design. *)
 
 BEGIN
-  FileSystem.Lookup(f, path, false);
+  FileSystem.Lookup(f, path, FALSE);
   found := (f.res = FileSystem.done);
   
   IF FileSystem.opened IN f.flags THEN
@@ -46,7 +46,7 @@
   highFactor, highWeight : FileSize;
 
 BEGIN
-  FileSystem.Lookup(f, path, false);
+  FileSystem.Lookup(f, path, FALSE);
   found := (f.res = FileSystem.done);
   
   IF NOT found THEN
@@ -60,7 +60,7 @@
   ELSE
     status := Failure;
     RETURN
-  END (* IF *)
+  END ; (* IF *)
   
   IF high = 0 THEN
     IF wouldOverflowFileSize(low) THEN
@@ -146,7 +146,7 @@
     RETURN
   END; (* IF *)
 
-  FileSystem.Lookup(f, path, false);
+  FileSystem.Lookup(f, path, FALSE);
   FileSystem.Rename(f, path);
   
   IF f.res = FileSystem.done THEN
@@ -198,6 +198,16 @@
 END wouldOverflowFileSize;
 
 
+(*
+   valueWouldOverflowFS - needs implementing --fixme--.
+*)
+
+PROCEDURE valueWouldOverflowFS (x: CARDINAL) : BOOLEAN ;
+BEGIN
+   RETURN FALSE  (* --fixme-- *)
+END valueWouldOverflowFS ;
+
+
 PROCEDURE addWouldOverflowFS ( n, m : CARDINAL ) : BOOLEAN;
 
 BEGIN


regards,
Gaius