Prior to this change the clang interface stubs format resembled
something ending with a symbol list like this:
Symbols:
a: { Type: Func }
This was problematic because we didn't actually want a map format and
also because we didn't like that an empty symbol list required
"Symbols: {}". That is to say without the empty {} llvm-ifs would crash
on an empty list.
With this new format it is much more clear which field is the symbol
name, and instead the [] that is used to express an empty symbol vector
is optional, ie:
Symbols:
- { Name: a, Type: Func }
or
Symbols: []
or
Symbols:
This further diverges the format from existing llvm-elftapi. This is a
good thing because although the format originally came from the same
place, they are not the same in any way.
Differential Revision: https://reviews.llvm.org/D76979
Second Landing Attempt:
This patch enables end to end support for generating ELF interface stubs
directly from clang. Now the following:
clang -emit-interface-stubs -o libfoo.so a.cpp b.cpp c.cpp
will product an ELF binary with visible symbols populated. Visibility attributes
and -fvisibility can be used to control what gets populated.
* Adding ToolChain support for clang Driver IFS Merge Phase
* Implementing a default InterfaceStubs Merge clang Tool, used by ToolChain
* Adds support for the clang Driver to involve llvm-ifs on ifs files.
* Adds -emit-merged-ifs flag, to tell llvm-ifs to emit a merged ifs text file
instead of the final object format (normally ELF)
Differential Revision: https://reviews.llvm.org/D63978
llvm-svn: 374061
This patch enables end to end support for generating ELF interface stubs
directly from clang. Now the following:
clang -emit-interface-stubs -o libfoo.so a.cpp b.cpp c.cpp
will product an ELF binary with visible symbols populated. Visibility attributes
and -fvisibility can be used to control what gets populated.
* Adding ToolChain support for clang Driver IFS Merge Phase
* Implementing a default InterfaceStubs Merge clang Tool, used by ToolChain
* Adds support for the clang Driver to involve llvm-ifs on ifs files.
* Adds -emit-merged-ifs flag, to tell llvm-ifs to emit a merged ifs text file
instead of the final object format (normally ELF)
Differential Revision: https://reviews.llvm.org/D63978
llvm-svn: 373538
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
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
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
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
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
Puyan Lotfi