Re: PING [PATCH v3] c++: Allow module name to be a single letter on Windows

[Torbjorn SVENSSON <torbjorn.svensson@foss.st.com>]

On 2022-11-28 12:21, Nathan Sidwell wrote:
> On 11/25/22 14:03, Torbjorn SVENSSON wrote:
>> Hi,
>>
>> Ping, https://gcc.gnu.org/pipermail/gcc-patches/2022-November/606528.html
> 
> ok, thanks!

Pushed.

> 
>>
>> Kind regards,
>> Torbjörn
>>
>> On 2022-11-17 14:20, Torbjörn SVENSSON wrote:
>>> v1 -> v2:
>>> Paths without "C:" part can still be absolute if they start with / or
>>> \ on Windows.
>>>
>>> v2 -> v3:
>>> Use alternative approach by having platform specific code in module.cc.
>>>
>>> Truth table for the new expression:
>>> c:\foo     -> true
>>> c:/foo     -> true
>>> /foo       -> true
>>> \foo       -> true
>>> c:foo      -> false
>>> foo        -> false
>>> ./foo      -> true
>>> .\foo      -> true
>>>
>>>
>>> Ok for trunk?
>>>
>>> ---
>>>
>>> On Windows, the ':' character is special and when the module name is
>>> a single character, like 'A', then the flatname would be (for
>>> example) 'A:Foo'. On Windows, 'A:Foo' is treated as an absolute
>>> path by the module loader and is likely not found.
>>>
>>> Without this patch, the test case pr98944_c.C fails with:
>>>
>>> In module imported at /src/gcc/testsuite/g++.dg/modules/pr98944_b.C:7:1,
>>> of module A:Foo, imported at 
>>> /src/gcc/testsuite/g++.dg/modules/pr98944_c.C:7:
>>> A:Internals: error: header module expected, module 'A:Internals' found
>>> A:Internals: error: failed to read compiled module: Bad file data
>>> A:Internals: note: compiled module file is 'gcm.cache/A-Internals.gcm'
>>> In module imported at /src/gcc/testsuite/g++.dg/modules/pr98944_c.C:7:8:
>>> A:Foo: error: failed to read compiled module: Bad import dependency
>>> A:Foo: note: compiled module file is 'gcm.cache/A-Foo.gcm'
>>> A:Foo: fatal error: returning to the gate for a mechanical issue
>>> compilation terminated.
>>>
>>> gcc/cp/ChangeLog:
>>>
>>>     * module.cc: On Windows, 'A:Foo' is supposed to be a module
>>>     and not a path.
>>>
>>> Tested on Windows with arm-none-eabi for Cortex-M3 in gcc-11 tree.
>>>
>>> Co-Authored-By: Yvan ROUX <yvan.roux@foss.st.com>
>>> Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>
>>> ---
>>>   gcc/cp/module.cc | 10 +++++++++-
>>>   1 file changed, 9 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
>>> index 0e9af318ba4..fa41a86213f 100644
>>> --- a/gcc/cp/module.cc
>>> +++ b/gcc/cp/module.cc
>>> @@ -13960,7 +13960,15 @@ get_module (tree name, module_state *parent, 
>>> bool partition)
>>>   static module_state *
>>>   get_module (const char *ptr)
>>>   {
>>> -  if (ptr[0] == '.' ? IS_DIR_SEPARATOR (ptr[1]) : IS_ABSOLUTE_PATH 
>>> (ptr))
>>> +  /* On DOS based file systems, there is an ambiguity with A:B which 
>>> can be
>>> +     interpreted as a module Module:Partition or Drive:PATH.  
>>> Interpret strings
>>> +     which clearly starts as pathnames as header-names and 
>>> everything else is
>>> +     treated as a (possibly malformed) named moduled.  */
>>> +  if (IS_DIR_SEPARATOR (ptr[ptr[0] == '.']) // ./FOO or /FOO
>>> +#if HAVE_DOS_BASED_FILE_SYSTEM
>>> +      || (HAS_DRIVE_SPEC (ptr) && IS_DIR_SEPARATOR (ptr[2])) // A:/FOO
>>> +#endif
>>> +      || false)
>>>       /* A header name.  */
>>>       return get_module (build_string (strlen (ptr), ptr));
>