mirror of
https://github.com/JakeHillion/drgn.git
synced 2024-12-23 09:43:06 +00:00
1cedca8ff4
Based on: c950e8a9 config: Fix spec file, add manpages and new GFDL license. With the following patches: configure: Add --disable-programs configure: Add --disable-shared configure: Fix -D_FORTIFY_SOURCE=2 check when CFLAGS contains -Wno-error libcpu: compile i386_lex.c with -Wno-implicit-fallthrough The plan is to stop relying on the distribution's version of elfutils and instead ship our own. This gives us freedom to assume that we're using the latest version and even ship our own patches (starting with a few build system improvements). More details are in scripts/update-elfutils.sh, which was used to generate this commit.
96 lines
3.0 KiB
Plaintext
96 lines
3.0 KiB
Plaintext
Fundamental design decision:
|
|
|
|
- the sizes of external and internal types are assumed to be the same.
|
|
This leaves byte ordering aside. While assuming this the code can be
|
|
greatly simplified and speed increases. Since no change violating this
|
|
assumption is in sight this is believed to be a worthwhile optimization.
|
|
|
|
- the ABI of the backend modules is not guaranteed. Really, no guarantee
|
|
whatsoever. We are enforcing this in the code. The modules and their
|
|
users must match. No third-party EBL module are supported or allowed.
|
|
The only reason there are separate modules is to not have the code for
|
|
all architectures in all the binaries.
|
|
|
|
- although the public libraries (libasm, libdw) have a stable API and are
|
|
backwards ABI compatible they, and the elfutils tools, do depend on each
|
|
others internals, and on internals of libelf to provide their interfaces.
|
|
So they should always be upgraded in lockstep when packaging the tools
|
|
and libraries separately. For one example of how to do that, see the
|
|
config/elfutils.spec.
|
|
|
|
Some notes:
|
|
|
|
- old GNU ld's behavior wrt DSOs seems to be severely broken.
|
|
|
|
y.o reference foo()
|
|
y1.o defines foo(), references bar()
|
|
y2.o defines bar()
|
|
libbar.so defines bar()
|
|
|
|
Running
|
|
|
|
gcc -o y y.o -lbar y1.o y2.o
|
|
|
|
uses the bar() definition from libbar.so and does not mention the definition
|
|
in y2.o at all (no duplicate symbol message). Correct is to use the
|
|
definition in y2.o.
|
|
|
|
|
|
y.o reference foo()
|
|
y1.o defines foo(), references bar()
|
|
y2.o in liby2.a defines bar()
|
|
libbar.so defines bar()
|
|
|
|
Running
|
|
|
|
gcc -o y y.o -lbar y1.o -ly3
|
|
|
|
has to use the definition in -lbar and not pull the definition from liby3.a.
|
|
|
|
|
|
- the old linker follows DT_NEEDED entries and adds the objects referenced
|
|
this way which define a symbol which is needed as a DT_NEEDED to the
|
|
generated binary. This is wrong since the DT_NEEDED changes the search
|
|
path in the object (which is breadth first).
|
|
|
|
|
|
- the old linker supported extern "C++", extern "java" in version scripts.
|
|
I believe this implementation is severly broken and needs a redesign
|
|
(how do wildcards work with these languages*?). Therefore it is left
|
|
out for now.
|
|
|
|
|
|
- what should happen if two sections in different files with the same
|
|
name have different types and/or the flags are different
|
|
|
|
|
|
- section names in input files are mostly irrelevant. Exceptions:
|
|
|
|
.comment/SHT_PROGBITS in strip, ld
|
|
|
|
.debug \
|
|
.line |
|
|
.debug_srcinfo |
|
|
.debug_sfnames |
|
|
.debug_aranges |
|
|
.debug_pubnames |
|
|
.debug_info |
|
|
.debug_abbrev |
|
|
.debug_line |
|
|
.debug_abbrev > DWARF sections in ld
|
|
.debug_line |
|
|
.debug_frame |
|
|
.debug_str |
|
|
.debug_loc |
|
|
.debug_macinfo |
|
|
.debug_weaknames |
|
|
.debug_funcnames |
|
|
.debug_typenames |
|
|
.debug_varnames /
|
|
|
|
Sections created in output files follow the naming of special section
|
|
from the gABI.
|
|
|
|
In no place is a section solely indentified by its name. Internal
|
|
references always use the section index.
|