Commit d90be200 authored by Brad King's avatar Brad King
Browse files

Fortran: Add support for GNU >= 4.9 compressed modules (#14975)

From the GCC 4.9 release notes for Fortran:

 https://gcc.gnu.org/gcc-4.9/changes.html
 "Module files: The version of the module files (.mod) has been
  incremented; additionally, module files are now compressed."

Teach cmDependsFortran::ModulesDiffer to look for the gzip magic numbers
at the beginning of the module file.  If found, assume the module was
produced by gfortran >= 4.9.  The modules do not appear to contain the
date as earlier versions did so we can compare the content directly
and do not actually need to decompress.
parent 55d6aa36
......@@ -765,7 +765,11 @@ bool cmDependsFortran::ModulesDiffer(const char* modFile,
const char* compilerId)
{
/*
gnu:
gnu >= 4.9:
A mod file is an ascii file compressed with gzip.
Compiling twice produces identical modules.
gnu < 4.9:
A mod file is an ascii file.
<bar.mod>
FORTRAN module created from /path/to/foo.f90 on Sun Dec 30 22:47:58 2007
......@@ -821,21 +825,30 @@ bool cmDependsFortran::ModulesDiffer(const char* modFile,
*/
if (strcmp(compilerId, "GNU") == 0 )
{
const char seq[1] = {'\n'};
const int seqlen = 1;
if(!cmDependsFortranStreamContainsSequence(finModFile, seq, seqlen))
// GNU Fortran 4.9 and later compress .mod files with gzip
// but also do not include a date so we can fall through to
// compare them without skipping any prefix.
unsigned char hdr[2];
bool okay = finModFile.read(reinterpret_cast<char*>(hdr), 2)? true:false;
finModFile.seekg(0);
if(!(okay && hdr[0] == 0x1f && hdr[1] == 0x8b))
{
// The module is of unexpected format. Assume it is different.
std::cerr << compilerId << " fortran module " << modFile
<< " has unexpected format." << std::endl;
return true;
}
const char seq[1] = {'\n'};
const int seqlen = 1;
if(!cmDependsFortranStreamContainsSequence(finStampFile, seq, seqlen))
{
// The stamp must differ if the sequence is not contained.
return true;
if(!cmDependsFortranStreamContainsSequence(finModFile, seq, seqlen))
{
// The module is of unexpected format. Assume it is different.
std::cerr << compilerId << " fortran module " << modFile
<< " has unexpected format." << std::endl;
return true;
}
if(!cmDependsFortranStreamContainsSequence(finStampFile, seq, seqlen))
{
// The stamp must differ if the sequence is not contained.
return true;
}
}
}
else if(strcmp(compilerId, "Intel") == 0)
......
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