Commit Graph

12 Commits

Author SHA1 Message Date
Richard Smith a21c8e14b6 When preprocessing with -frewrite-imports and -fmodule-file=, do not pass all
modules to preprocessing of nested .pcm files.

Making those module files available results in loading more .pcm files than
necessary, and potentially in misbehavior if a module makes itself visible
during its own compilation (as parts of that module that have not yet been
processed would then become visible).

llvm-svn: 306320
2017-06-26 19:39:25 +00:00
Richard Smith 1893475d95 Retain header search and preprocessing options from AST file when emitting
preprocessed text for an AST file.

llvm-svn: 304756
2017-06-06 00:32:01 +00:00
Richard Smith 6b19934915 Attempt to fix Windows buildbot failure due to mismatching directory separators in preprocessed output.
llvm-svn: 304727
2017-06-05 18:39:31 +00:00
Richard Smith ab75597dda Rather than rejecting attempts to run preprocessor-only actions on AST files,
replay the steps taken to create the AST file with the preprocessor-only action
installed to produce preprocessed output.

This can be used to produce the preprocessed text for an existing .pch or .pcm
file.

llvm-svn: 304726
2017-06-05 18:10:11 +00:00
Richard Smith 040e12662a Support lazy stat'ing of files referenced by module maps.
This patch adds support for a `header` declaration in a module map to specify
certain `stat` information (currently, size and mtime) about that header file.
This has two purposes:

- It removes the need to eagerly `stat` every file referenced by a module map.
  Instead, we track a list of unresolved header files with each size / mtime
  (actually, for simplicity, we track submodules with such headers), and when
  attempting to look up a header file based on a `FileEntry`, we check if there
  are any unresolved header directives with that `FileEntry`'s size / mtime and
  perform deferred `stat`s if so.

- It permits a preprocessed module to be compiled without the original files
  being present on disk. The only reason we used to need those files was to get
  the `stat` information in order to do header -> module lookups when using the
  module. If we're provided with the `stat` information in the preprocessed
  module, we can avoid requiring the files to exist.

Unlike most `header` directives, if a `header` directive with `stat`
information has no corresponding on-disk file the enclosing module is *not*
marked unavailable (so that behavior is consistent regardless of whether we've
resolved a header directive, and so that preprocessed modules don't get marked
unavailable). We could actually do this for all `header` directives: the only
reason we mark the module unavailable if headers are missing is to give a
diagnostic slightly earlier (rather than waiting until we actually try to build
the module / load and validate its .pcm file).

Differential Revision: https://reviews.llvm.org/D33703

llvm-svn: 304515
2017-06-02 01:55:39 +00:00
Richard Smith 8b70610494 [modules] When compiling a preprocessed module map, look for headers relative
to the original module map.

Also use the path and name of the original module map when emitting that
information into the .pcm file. The upshot of this is that the produced .pcm
file will track information for headers in their original locations (where the
module was preprocessed), not relative to whatever directory the preprocessed
module map was in when it was built.

llvm-svn: 304346
2017-05-31 20:56:55 +00:00
Richard Smith 54f0440c1f [modules] Switch from inferring owning modules based on source location to
inferring based on the current module at the point of creation.

This should result in no functional change except when building a preprocessed
module (or more generally when using #pragma clang module begin/end to switch
module in the middle of a file), in which case it allows us to correctly track
the owning module for declarations. We can't map from FileID to module in the
preprocessed module case, since all modules would have the same FileID.

There are still a couple of remaining places that try to infer a module from a
source location; I'll clean those up in follow-up changes.

llvm-svn: 303322
2017-05-18 02:29:20 +00:00
Richard Smith 4a3751ff24 If we are building a module, and we read a second description of the same
module from a different module map, ignore it.

This happens during builds of preprocessed modules (where it is harmless).

llvm-svn: 302463
2017-05-08 20:30:47 +00:00
Richard Smith 8128f3327f Add support for building modules from preprocessed source.
To support this, an optional marker "#pragma clang module contents" is
recognized in module map files, and the rest of the module map file from that
point onwards is treated as the source of the module. Preprocessing a module
map produces the input module followed by the marker and then the preprocessed
contents of the module.

Ignoring line markers, a preprocessed module might look like this:

  module A {
    header "a.h"
  }
  #pragma clang module contents
  #pragma clang module begin A
  // ... a.h ...
  #pragma clang module end

The preprocessed output generates line markers, which are not accepted by the
module map parser, so -x c++-module-map-cpp-output should be used to compile
such outputs.

A couple of major parts do not work yet:

1) The files that are listed in the module map must exist on disk, in order to
   build the on-disk header -> module lookup table in the PCM file. To fix
   this, we need the preprocessed output to track the file size and other stat
   information we might use to build the lookup table.

2) Declaration ownership semantics don't work properly yet, since mapping from
   a source location to a module relies on mapping from FileIDs to modules,
   which we can't do if module transitions can occur in the middle of a file.

llvm-svn: 302309
2017-05-05 22:18:51 +00:00
Richard Smith d13863008b Add #pragma clang module begin/end pragmas and generate them when preprocessing a module.
These pragmas are intended to simulate the effect of entering or leaving a file
with an associated module. This is not completely implemented yet: declarations
between the pragmas will not be attributed to the correct module, but macro
visibility is already functional.

Modules named by #pragma clang module begin must already be known to clang (in
some module map that's either loaded or on the search path).

llvm-svn: 302098
2017-05-04 00:29:54 +00:00
Richard Smith c51c38b4ec Add pragma to perform module import and use it in -E output.
Many of our supported configurations support modules but do not have any
first-class syntax to perform a module import. This leaves us with a problem:
there is no way to represent the expansion of a #include that imports a module
in the -E output for such languages. (We don't want to just leave it as a
#include because that requires the consumer of the preprocessed source to have
the same file system layout and include paths as the creator.)

This patch adds a new pragma:

  #pragma clang module import MODULE.NAME.HERE

that imports a module, and changes -E and -frewrite-includes to use it when
rewriting a #include that maps to a module import. We don't make any attempt
to use a native language syntax import if one exists, to get more consistent
output. (If in the future, @import and #include have different semantics in
some way, the pragma will track the #include semantics.)

llvm-svn: 301725
2017-04-29 00:34:47 +00:00
Richard Smith f74d946624 Move functionality for handling module maps as inputs from the -emit-module
action to the general FrontendAction infrastructure.

This permits applying -E, -ast-dump, -fsyntax-only, and so on to a module map
compilation. (The -E form is not currently especially useful yet as there's no
good way to take the output and use it to actually build a module.)

In order to support this, -cc1 now accepts -x <lang>-module-map in all cases
where it accepts -x <lang> for a language we can parse (not ir/ast). And for
uniformity, we also accept -x <lang>-header for all such languages (we used
to reject for cuda and renderscript), and -x <lang>-cpp-output for all such
languages (we used to reject for c, cl, and renderscript).

(None of these new alternatives are accepted by the driver yet, so no
user-visible changes.)

llvm-svn: 301610
2017-04-28 01:49:42 +00:00