Sebastian Holtermann authored Apr 19, 2016 and Brad King committed Apr 22, 2016

A qrc_NAME.cpp file generated from NAME.qrc in the directory
CMAKE_CURRENT_SOURCE_DIR/SUBDIR
will be generated in the directory
CMAKE_CURRENT_BINARY_DIR/TARGETNAME_automoc.dir/SUBDIR

Sebastian Holtermann authored Apr 19, 2016 and Brad King committed Apr 22, 2016

Not included moc files generated from a source file in
CMAKE_CURRENT_SOURCE_DIR/SUBDIR
will be generated in the directory
CMAKE_CURRENT_BINARY_DIR/TARGETNAME_automoc.dir/SUBDIR/

Sebastian Holtermann authored Apr 18, 2016 and Brad King committed Apr 22, 2016

The test exits with an error if two or more source files
would generate the same moc file.

This takes a std::string&, so directly pass the object to it instead of
converting back and forth.

All callers already have one, and it was immediately converted to one
internally. Just keep the old one around, and only modify it when needed.

All callers already have these objects, and it is only passed to other methods
taking such, so avoid all conversions in between.

This function already takes a const std::string&, no need to convert the input
to a char* before passing it in.

Running the testsuite this function is entered more than 126,000 times. Reorder
the code flow so that a conversion from char* to std::string is only done when
the cache entry is a path one, which happens only ~50 times during the
testsuite.

Sebastian Holtermann authored Apr 18, 2016 and Brad King committed Apr 19, 2016

The single map allows name collision testing (in a later commit)

Sebastian Holtermann authored Apr 18, 2016 and Brad King committed Apr 19, 2016

While at it, simplify the signature and avoid a trailing separator.

All callers now pass a full backtrace so we do not need the alternative
that takes a cmListFileContext directly.  Drop this overload to remove
the code duplication.

This information is now kept in cmMakefile::Backtrace.

Since commit v3.4.0-rc1~321^2~2 (Genex: Store a backtrace, not a pointer
to one, 2015-07-08) we treat cmListFileBacktrace instances as
lightweight values.  This was true at the time only because the
backtrace information was kept in the cmState snapshot hierarchy.
However, that forced us to accumulate a lot of otherwise short-lived
snapshots just to have the backtrace fields available for reference by
cmListFileBacktrace instances.  Recent refactoring made backtrace
instances independent of the snapshot hierarchy to avoid accumulating
short-lived snapshots.  This came at the cost of making backtrace values
heavy again, leading to lots of string coying and slower execution.

Fix this by refactoring cmListFileBacktrace to provide value semantics
with efficient shared storage underneath.  Teach cmMakefile to maintain
its call stack using an instance of cmListFileBacktrace.  This approach
allows the current backtrace to be efficiently saved whenever it is
needed.

Also teach cmListFileBacktrace the notion of a file-level scope.  This
is useful for messages about the whole file (e.g. during parsing) that
are not specific to any line within it.  Push the CMakeLists.txt scope
for each directory and never pop it.  This ensures that we always have
some context information and simplifies cmMakefile::IssueMessage.
Push/pop a file-level scope as each included file is processed.  This
supersedes cmParseFileScope and improves diagnostic message context
information in a few places.  Fix the corresponding test cases to expect
the improved output.

Ensure the destination directory exists before creating symlinks in it.

Changes during post-3.3/pre-3.4 development refactored storage of most
configure-time information, including variable bindings and function
scopes.  All scopes (even short-lived) were kept persistently for
possible future debugging features, causing huge accumulated memory
usage.  This was mostly addressed by commit v3.4.1~4^2 (cmState: Avoid
accumulating snapshot storage for short-lived scopes, 2015-11-24).

Since then we still keep short-lived scopes when they are needed for a
backtrace.  This is because since commit v3.4.0-rc1~378^2
(cmListFileBacktrace: Implement in terms of cmState::Snapshot,
2015-05-29) backtraces have been lightweight objects that simply point
into the snapshot tree.  While the intention of this approach was to
avoid duplicating the call stack file path strings, the cost turned out
to be holding on to the entire call stack worth of scope snapshots,
which is much worse.

Furthermore, since commit v3.4.0-rc2~1^2 (cmIfCommand: Issue CMP0054
warning with appropriate context, 2015-10-20) all conditions used in
`if()` commands hold a backtrace for use in diagnostic messages.  Even
though the backtrace is short-lived it still causes the scope snapshot
to be kept.  This means that code like

    function(foo)
      if(0)
      endif()
    endfunction()

    foreach(i RANGE 1000000)
      foo()
    endforeach()

accumulates storage for the function call scope snapshots.

Fix this by partially reverting commit v3.4.0-rc1~378^2 and saving the
entire call stack during cmListFileBacktrace construction.  This way
we can avoid keeping short-lived scope snapshot storage in all cases.

The bottom of the call stack is always a long-lived snapshot and can be
saved for later use with cmOutputConverter.

In commit v2.8.4~32^2~14 (Use cmake::IssueMessage for warnings,
2010-12-07) these warnings became formatted.  It is more informative to
give the full call stack with such warnings.  Also it is easier to
implement warnings with a full call stack because we do not have to
construct a custom backtrace with only the top.

This method was added by commit v3.4.0-rc1~424^2~6 (cmLocalGenerator:
Add IssueMessage method, 2015-06-13) in order to reduce callers'
dependency on cmMakefile.  Currently the implementation of
cmLocalGenerator::IssueMessage is just a copy of the post-configure code
path in cmMakefile::IssueMessage.  De-duplicate the implementation by
simply calling the cmMakefile copy for now.  This will simplify upcoming
refactoring of backtraces.  The dependency on cmMakefile can be removed
by future work once that is done.