Restructure the ELF handling to be completely agnostic to the OS.
Rather than usng the loader to query the section information, use the
linker to construct linker tables and synthetic markers for the
beginning and of the table. Save off the values of these pointers and
pass them along through the constructor to the runtime for registration.
This removes the need for the begin/end objects. Remove the special
construction of the begin/end objects through the special assembly
constructs, preferring to do this in C with a bit of inline assembly to
ensure that the section is always allocated.
Remove the special handling for the various targets, the empty object
file can be linked on all the targets.
The new object file has no requirements on the ordering. It needs to
simply be injected into the link.
Name the replacement file `swiftrt.o` mirroring `crt.o` from libc. Merge
the constructor and the definition into a single object file.
This approach is generally more portable, overall simpler to implement,
and more robust.
Thanks to Orlando Bassotto for help analyzing some of the odd behaviours
when switching over.
- Create separate swift_begin.o/swift_end.o for lib/swift and
lib/swift_static. The static swift_begin.o does not call
swift_addNewDSOImage() at startup.
- Update ToolChains.cpp to use the correct swift_begin.o/swift_end.o
files for the `-static-stdlib` and `-static-executable` options.
- For ELF targets, keep track of shared objects as they are
dynamically loaded so that section data can be added to
the protocol conformance and type metadata caches after
initialisation (rdar://problem/19045112).
- Revert the use of SWIFT_RUNTIME_EXPORT in ImageInspectionELF.cpp and
fix the unittests by explicitly adding the file to the list
- Revert the change of section data names
- Add ImageInspectionStatic.cpp to lookup protocol conformance
and metadata sections in static binaries
- For Linux, build libswiftImageInspectionShared.a and
libswiftImageInspectionStatic.a for linking with libswiftCore.a.
This allows static binaries to be built without linking to
libdl. libswiftImageInspectionShared (ImageInspectionELF.cpp) is
automatically compiled into libswiftCore.so
- Adds -static-executable option to swiftc to use along with
-emit-executable that uses linker arguments in
static-executable-args.lnk. This also requires a libicu
to be compiled using the --libicu which has configure options
that dont require libdl for accessing ICU datafiles
- Static binaries only work on Linux at this time
