Commit Graph

6 Commits

Author SHA1 Message Date
Puyan Lotfi e782192d5e [clang][IFS][test][NFC] Tightening up clang-ifs tests to use -cc1 more often.
Unless the test is explicitly testing a driver feature if clang
interface stubs I have changed the tests to use %clang_cc1. This should
make some changes I plan to make to the driver job pipeline cause fewer
test changes and breakages.
2019-11-14 02:25:22 -05:00
Puyan Lotfi 926f4f76c3 [clang][ifs] Dropping older experimental interface stub formats.
I've been working on a new tool, llvm-ifs, for merging interface stub files
generated by clang and I've iterated on my derivative format of TBE to a newer
format. llvm-ifs will only support the new format, so I am going to drop the
older experimental interface stubs formats in this commit to make things
simpler.

Differential Revision: https://reviews.llvm.org/D66573

llvm-svn: 369719
2019-08-22 23:44:34 +00:00
Puyan Lotfi 678e19d80c [NFC] Fix for InterfaceStubs tests (adding REQUIRES: x86-registered-target).
clang-hexagon-elf bot was failing with:

'No available targets are compatible with triple "x86_64-unknown-linux-gnu"'

Adding a "// REQUIRES: x86-registered-target" to these tests to quiet the bot.

llvm-svn: 363963
2019-06-20 18:28:21 +00:00
Puyan Lotfi 68f29dac4b [clang-ifs] Clang Interface Stubs, first version (second landing attempt).
This change reverts r363649; effectively re-landing r363626. At this point
clang::Index::CodegenNameGeneratorImpl has been refactored into
clang::AST::ASTNameGenerator. This makes it so that the previous circular link
dependency no longer exists, fixing the previous share lib
(-DBUILD_SHARED_LIBS=ON) build issue which was the reason for r363649.

Clang interface stubs (previously referred to as clang-ifsos) is a new frontend
action in clang that allows the generation of stub files that contain mangled
name info that can be used to produce a stub library. These stub libraries can
be useful for breaking up build dependencies and controlling access to a
library's internal symbols. Generation of these stubs can be invoked by:

clang -fvisibility=<visibility> -emit-interface-stubs \
                                -interface-stub-version=<interface format>

Notice that -fvisibility (along with use of visibility attributes) can be used
to control what symbols get generated. Currently the interface format is
experimental but there are a wide range of possibilities here.

Currently clang-ifs produces .ifs files that can be thought of as analogous to
object (.o) files, but just for the mangled symbol info. In a subsequent patch
I intend to add support for merging the .ifs files into one .ifs/.ifso file
that can be the input to something like llvm-elfabi to produce something like a
.so file or .dll (but without any of the code, just symbols).

Differential Revision: https://reviews.llvm.org/D60974

llvm-svn: 363948
2019-06-20 16:59:48 +00:00
Fangrui Song 2d94dd812f Revert D60974 "[clang-ifs] Clang Interface Stubs, first version."
This reverts commit rC363626.

clangIndex depends on clangFrontend. r363626 adds a dependency from
clangFrontend to clangIndex, which creates a circular dependency.

This is disallowed by -DBUILD_SHARED_LIBS=on builds:

    CMake Error: The inter-target dependency graph contains the following strongly connected component (cycle):
      "clangFrontend" of type SHARED_LIBRARY
        depends on "clangIndex" (weak)
      "clangIndex" of type SHARED_LIBRARY
        depends on "clangFrontend" (weak)
    At least one of these targets is not a STATIC_LIBRARY.  Cyclic dependencies are allowed only among static libraries.

Note, the dependency on clangIndex cannot be removed because
libclangFrontend.so is linked with -Wl,-z,defs: a shared object must
have its full direct dependencies specified on the linker command line.

In -DBUILD_SHARED_LIBS=off builds, this appears to work when linking
`bin/clang-9`. However, it can cause trouble to downstream clang library
users. The llvm build system links libraries this way:

    clang main_program_object_file ... lib/libclangIndex.a ...  lib/libclangFrontend.a -o exe

libclangIndex.a etc are not wrapped in --start-group.

If the downstream application depends on libclangFrontend.a but not any
other clang libraries that depend on libclangIndex.a, this can cause undefined
reference errors when the linker is ld.bfd or gold.

The proper fix is to not include clangIndex files in clangFrontend.

llvm-svn: 363649
2019-06-18 05:52:39 +00:00
Puyan Lotfi 8df7f1a218 [clang-ifs] Clang Interface Stubs, first version.
Clang interface stubs (previously referred to as clang-ifsos) is a new frontend
action in clang that allows the generation of stub files that contain mangled
name info that can be used to produce a stub library. These stub libraries can
be useful for breaking up build dependencies and controlling access to a
library's internal symbols. Generation of these stubs can be invoked by:

clang -fvisibility=<visibility> -emit-interface-stubs \
                                -interface-stub-version=<interface format>

Notice that -fvisibility (along with use of visibility attributes) can be used
to control what symbols get generated. Currently the interface format is
experimental but there are a wide range of possibilities here.

Differential Revision: https://reviews.llvm.org/D60974

llvm-svn: 363626
2019-06-17 22:46:54 +00:00