GitLab

Run clang-tidy's readability-redundant-string-cstr checker.
Ignore findings in kwsys.

Use clang-tidy's performance-unnecessary-value-param checker to find
value parameter declarations of expensive to copy types that are not
modified inside the function.  Ignore findings in kwsys.
After applying the fix-its, manually change `const T&` to `T const&`.

Kitware Robot authored May 16, 2016 and Brad King committed May 16, 2016

Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.

* If you reached this commit for a line in `git blame`, re-run the blame
  operation starting at the parent of this commit to see older history
  for the content.

* See the parent commit for instructions to rebase a change across this
  style transition commit.

Sort include directives within each block (separated by a blank line) in
lexicographic order (except to prioritize `sys/types.h` first).  First
run `clang-format` with the config file:

    ---
    SortIncludes: false
    ...

Commit the result temporarily.  Then run `clang-format` again with:

    ---
    SortIncludes: true
    IncludeCategories:
      - Regex:    'sys/types.h'
        Priority: -1
    ...

Commit the result temporarily.  Start a new branch and cherry-pick the
second commit.  Manually resolve conflicts to preserve indentation of
re-ordered includes.  This cleans up the include ordering without
changing any other style.

Use the following command to run `clang-format`:

    $ git ls-files -z -- \
        '*.c' '*.cc' '*.cpp' '*.cxx' '*.h' '*.hh' '*.hpp' '*.hxx' |
      egrep -z -v '(Lexer|Parser|ParserHelper)\.' |
      egrep -z -v '^Source/cm_sha2' |
      egrep -z -v '^Source/(kwsys|CursesDialog/form)/' |
      egrep -z -v '...

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.

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.

We need to keep only certain snapshot types and their ancestors.
Also keep those needed for backtraces.

We enforce policy push/pop balance around any scope that pushes/pops a
snapshot.  Therefore a snapshot may never reference entries of
PolicyStack that were created in nested scopes.  Free storage of
short-lived policy stack entries when they are popped.

Logically the method pushes a nested scope on top of a given scope
because the "up" pointer sequence forms a stack independent of any
other branches of the tree.

Everywhere we use cmMakefile::ScopePushPop to manage variable scopes
also expects policy scopes to be balanced.  There is no place that we
use cmMakefile::PolicyPushPop without also using ScopePushPop.  Relieve
PolicyPushPop of responsibility for policy scope balance checks by
moving it to ScopePushPop.

Since commit v3.4.0-rc1~179^2~1 (cmState: Add a VariableScope snapshot
type, 2015-08-23) the snapshot stack may have a VariableScopeType entry.
Skip over these when constructing the call stack, just as we do for
policy scopes.  Otherwise we report the command causing the variable
scope to be entered twice (e.g. find_package while loading a package
version file).

Add new API for the subdirs command to cmState.

This fixes a regression introduced in commit f716460e (cmMakefile: Move
invokation to initialize snapshot., 2015-10-06).

Don't leave this as cmMakefile responsibility.

Don't leave this as cmMakefile responsibility.

Don't leave this as cmMakefile responsibility.

Don't leave this as cmMakefile responsibility.

This is the appropriate snapshot for future use.  Existing users
of this method are mostly just calling GetDirectory on the result,
but the progress tracking of the Makefile generator needs a consistent
snapshot to be used, so the end snapshot should be consistently used.

This is a change in behavior from CMake 3.3, but there is no semantic meaning
to empty entries in buildsystem properties.  This also restores behavior to
that of CMake 2.8.10.