Allows to create dynamic executables, using the code path
for TCC_OUTPUT_DLL but add an .interp header (plus a FLAGS_1
entry in the dynamic section to make 'readelf' say "PIE")
Introduces TCC_OUTPUT_DYN as alias for TCC_OUTPUT_DLL.
There is no runtime option, only one to configure:
./configure --config-pie
100 insertions(+), 76 deletions(-)
Better avoid global variables, at least in new code.
tccdbg.c hopefully should be logically identical to the
former parts in tccgen/elf.c (s1 tccstate added in some
places)
tccelf.c: dwarf linkage seems special per dwarf rather
than special per target.
/* Use "-g" as alias for "-g1". Use "-g0" to disable debug */
So not using -g is now the alias for -g0 ?!?
This reverts commit 8759b2581d.
This reverts commit 3ce7bc6efc.
This reverts commit 5fb582ab7f.
This reverts commit aea68dbb40.
This reverts commit fa9c31c3db.
This reverts commit b3bebdb20a.
This reverts commit ecf8e5a00e.
This reverts commit fe6b5c08dc.
This reverts commit e2e5377e7b.
This reverts commit 1cd7998905.
This if for clang (pre)release 15.0.0.
tccrun.c:
- update directory/filename read. clang has extra md5 section
- start with filename 0 instead of 1. clang starts at 0
- change dwarf_read_32/dwarf_read_64 into macros
x86_64-link.c:
- Add support for R_X86_64_DTPOFF64/R_X86_64_TPOFF64. Needed by clang
tests/tcctest.c:
- add prototypes for puts/alloca. clang fails with error
- disable other_constraints_test for clang. clang prints 1 instead of 0
The new gcc12 release does not support stabs any more.
This was a good reason to add support for dwarf.
The stabs code still works and is used if configure option --dwarf
is not used.
Tested on x86_64, i386, arm, arm64, riscv64 with dwarf-5.
Some debuggers may not support dwarf-5. Try using older dwarf versions
i that case.
The tccmacho.c code probably need some support for dwarf.
arm-gen.c, arm64-gen.c, i386-gen.c, riscv64-gen.c, x86_64-gen.
- fix get_sym_ref symbol size
arm-link.c, arm64-link.c, i386-link.c, riscv64-link.c, x86_64-link.c
- add R_DATA_32U
libtcc.c:
- parse -gdwarf option
tcc.c:
- add dwarf option
tcc.h:
- add dwarf option and sections
tccelf.c:
- init dwarf sections
- avoid adding sh_addr for dwarf sections
- remove dwarf relocs for output dll
- add dwarf sections for tccrun
tccgen.c:
- add dwarf defines + global data
- add dwarf_* functions
- mix dwarf code with stabs code
- a trick is used to emit function name in .debug_line section so
only this section has to be parsed instead of .debug_info and
.debug_abbrev.
- fix init debug_modes
tccrun.c:
- add dwarf sections in rt_context
- init them in tcc_run
- add new dwarf code rt_printline_dwarf to find file/function
dwarf.h:
- New file
tcc-doc.texi:
- document dwarf
configure:
- add dwarf option
lib/Makefile
- change -gstabs into -gdwarf
lib/bt-exe.c, tests/tests2/Makefile, tests/tests2/126_bound_global:
- Add __bound_init call
- Add new testcase to test it
Currently tcc does not use lazy binding. It puts all relocations in the RELX
section and solve them all at startup.
This was not working on bsd.
tcc.h:
- New RELPLT_SECTION_FMT for plt relocations
- New entry relocplt in struct Section
tccelf.c:
- put_elf_reloca: put R_JMP_SLOT in relocplt section
- build_got_entries*: Use two passes because R_JMP_SLOT and R_GLOB_DAT
can not be intermixed on some targets (arm, arm64)
- layout_sections: Calculate correct size relocplt section for DT_ values.
Make sure relocplt is last
- fill_dynamic: Add DT_ values when got is filled
move DT_VERSYM because dynamic linker cannot handle it standone
- Add note section for NetBSD
arm-link.c/arm64-link.c/i386-link.c/riscv64-link.c/x86_64-link.c:
- fill got table with pointer to plt section or symbol value in case
of TCC_OUTPUT_MEMORY
arm-link.c/arm64-link.c:
- fix offset first plt entry
i386-link.c/x86_64-link.c:
- use correct reloc entry
- use relofs - sizeof (ElfW_Rel) because the reloc is already done
lib/bcheck.c:
- no __libc_freeres on FreeBSD and NetBSD
tests/Makefile:
- Add -fno-stack-protector for OpenBSD
tests/tests2/Makefile:
- disable 106_pthread/114_bound_signal
The BOUNDS_CHECKING_ON/BOUNDS_CHECKING_OFF is not working for
signal/sigaction/fork. The reason is that the code stops bound checking
for the whole application. This result in wrong handling of
__bound_local_new/__bound_local_delete and malloc/calloc/realloc/free.
Consider the following code:
void tst(int n) {
int i, arr[n];
for (i = 0; i < n; i++) arr[i] = 0;
}
void *some_thread(void *dummy) {
while (running) { tst(10); tst(20); }
}
void signal_handler(int sig) { ... }
When the signal handler is called the some_thread code can be interrupted when
is just registered the arr[10] data. When the signal handler is leaved the
arr[10] is still registered and did not see the call to deregister arr[10] and
then register arr[20]. The code resumes when tst(20) is running. This results
in a bound checking error when i >= 10.
To solve the above problem I changed the bound checking code to use
tls (thread local storage) for the no_checking variable.
This also makes it now possible to redirect signal/sigaction/fork code
through the bound checking library and disable checking when a signal is
running and to correct the bounds_sem for the fork child process.
The BOUNDS_CHECKING_ON/BOUNDS_CHECKING_OFF is not needed any more for
signal/sigaction/fork. In fact I could remove them from all my applications.
The use of the tls function code slows down the code by about 10%.
So if the slowdown due to bound checking was 5. It is now 5.5 times slower.
For x86_64/i386 I also allowed to use __thread variable in bcheck.c when
compiled with gcc with:
make x86_64-libtcc1-usegcc=yes
make i386-libtcc1-usegcc=yes
This makes code run faster due to use of gcc and __thread variable.
With the __thread variable there is no 10% slowdown.
For other targets this does not work because stabs is not supported.
Changes:
lib/bcheck.c:
- Add TRY_SEM
- Add HAVE_SIGNAL/HAVE_SIGACTION/HAVE_FORK/HAVE_TLS_FUNC/HAVE_TLS_VAR
- HAVE_SIGNAL: redirect signal() call if set.
- HAVE_SIGACTION: redirect sigaction() call if set.
- HAVE_FORK: redirect fork() call if set.
- HAVE_TLS_FUNC: If target has tls function calls.
- HAVE_TLS_VAR: If target has __thread tls support.
- Replace all no_checking refecrences to NO_CHECKING_SET/NO_CHECKING_GET macros
tcc-doc.texi:
- Remove examples for signal/sigaction/fork code.
- Add some explanation for signal/sigaction/fork code.
- Add documentaion for __bounds_checking().
tccelf.c:
- Add support for SHF_TLS
tests/tests2/114_bound_signal.c:
- Remove BOUNDS_CHECKING_ON/BOUNDS_CHECKING_OFF
- Add code to trigger failure when tls is not working.
x86_64-link.c:
- Add support for R_X86_64_TLSGD/R_X86_64_TLSLD/R_X86_64_DTPOFF32/R_X86_64_TPOFF32
i386-link.c:
- Add support for R_386_TLS_GD/R_386_TLS_LDM/R_386_TLS_LDO_32/R_386_TLS_LE
tested on win32/64 to pass the tests when enabled
- libtcc.c :
let tcc define __leading_underscore if enabled
tcc_add_symbol() : add _ automatically
- tccelf.c : remove tcc_get_symbol_err(), find_c_sym()
currently symbol length is limited to 256 in several
places, so we can use a fixed local buffer for now as well.
- win32/lib/crtinit.c : new file for init/fini
- lib/*.S, tests7* : use __leading_underscore
- bt-log.c: this file wont work relibaly if compiled with gcc
This makes it possible to get backtraces with executables
(including DLLs/SOs) like we had it already with -g -run.
Option -b includes -bt, and -bt includes -g.
- new file lib/bt-exe.c: used to link rt_printline and the
exception handler from tccrun.c into executables/DLLs.
- new file lib/bt-log.c: provides a function that may be
called from user code to print out a backtrace with a
message (currently for i386/x86_64 only):
int (*tcc_backtrace)(const char *fmt, ...);
As an extra hack, if 'fmt' is prefixed like "^file.c^..."
then the backtrace will skip calls from within 'file.c'.
- new file lib/bt-dll.c: used on win32 to link the backtrace
and bcheck functions with the main module at runtime
- bcheck.c: now uses the tcc_backtrace function from above
- tccgen.c: minor cleanups
- tccelf.c: stab sections get SHF_ALLOC for easy access.
Also in relocate_section(): 64bit relocations for stabs
in DLLs cannot work. To find DLL addresses, the DLL base
is added manually in tccrun.c via rc.prog_base instead.
- tccpe.c: there are some changes to allow merging sections,
used to merge .finit_array into .data in the first place.
- tccpp.c: tcc -run now #defines __TCC_RUN__
also: refactor a line in tal_realloc that was incompatible
with bcheck
- tcctest.c: fixed a problem with r12 which tcc cannot preserve
as well as gcc does.
- tests2/112_backtrace.c: test the feature and the bcheck test18
that previously was in boundtest.c
Add __attribute__((constructor)) to __bounds_init.
- remove tcc_add_bcheck from i386-link.c and x86_64-link.c
- add simplified tcc_add_bcheck to tccelf.c
- Update tccrun.c to call constructor/destructor.
Set dynsym sh_info to number of local symbols in tccelf.c
Reduce stack size when bounds checking is enabled.
Added variable TCC_LIBBCHECK for windows support.
Add signal stack to detect stack overflow.
Add all & parameters in lbound_section and remove them if not used.
Close fd in tcc_relocate in tccrun.c
Fix section type constructor/destructor in tccelf.c
Add check code in tests/boundtest.c for mem/str functions.
Remove -ba from documentation.
Add bounds check signal info in documentation.
bcheck.c:
- Fix initial_pool alignment.
. Fix printf statements.
. Add prototypes for all external interface functions.
- Add TCC_BOUNDS_WARN_POINTER_ADD environment variable.
. Add ctype and errno data.
- Fix alloca when multithreading is used.
- Add lock for __bound_checking and __bound_never_fatal.
- Catch pthread_create and use locks when called.
- Detect in loaded in shared lib and use locks when found
- Use spin locks instead of semaphore locks.
- Make spin locked code as small as possible.
- Fix mem/str functions checking.
- Fix overlap checking mem/str functions.
- revert Makefiles to state before last bcheck additions
Instead, just load bcheck.o explicitly if that is
what is wanted.
- move tcc_add_bcheck() to the <target>-link.c files and
remove revently added arguments. This function is to
support tccelf.c with linking, not for tccgen.c to
support compilation.
- remove -ba option: It said:
"-ba Enable better address checking with bounds checker"
Okay, if it is better then to have it is not an option.
- remove va_copy. It is C99 and we try to stay C89 in tinycc
when possible. For example, MS compilers do not have va_copy.
- win64: revert any 'fixes' to alloca
It was correct as it was before, except for bound_checking
where it was not implemented. This should now work too.
- remove parasitic filename:linenum features
Such feature is already present with rt_printline in
tccrun.c. If it doesn't work it can be fixed.
- revert changes to gen_bounded_ptr_add()
gen_bounded_ptr_add() was working as it should before
(mostly). For the sake of simplicity I switched it to
CDECL. Anyway, FASTCALL means SLOWCALL with tinycc.
In exchange you get one addition which is required for
bounds_cnecking function arguments. The important thing
is to check them *BEFORE* they are loaded into registers.
New function gbound_args() does that.
In any case, code instrumentation with the bounds-check
functions as such now seems to work flawlessly again,
which means when they are inserted as NOPs, any code that
tcc can compile, seems to behave just the same as without
them.
What these functions then do when fully enabled, is a
differnt story. I did not touch this.
The bounds checking code has now enabled gen_bounded_ptr_add tests.
This makes the code slower but finds more errors.
I had to correct some things in tcc to make it work.
- Fixed off by one in lib/bcheck.c
- Corrected tccelf.c sym_versions.
- Disabled USE_TAL when using bounds checking.
- Fixed cstr_printf va_start.
- Fixed tests/tests2/46_grep.c off by one error.
- Updated gen_bounded_ptr_add in x86_64-gen.c
- Fixed x86_64-link.c pointer diff.
For gen_vla_alloc now always use alloca call when bounds checking.
Added line/filename in %rax before bound calls to find location of error.
This allows creation of TCCStates and operation with API
calls independently from each other, even from threads.
Frontend (option parsing/libtcc.c) and backend (linker/tccelf.c)
now depend only on the TCCState (s1) argument.
Compilation per se (tccpp.c, tccgen.c) is still using
globals for convenience. There is only one entry point
to this section which is tcc_compile() which is protected
by a semaphore.
There are some hacks involved to avoid too many changes,
as well as some changes in order to avoid too many hacks ;)
The test libtcc_test_mt.c shows the feature. Except this
new file the patch adds 87 lines overall.
this is enough to let me link a tcctest.c compiled by GCC
using some current debian sid riscv64 system. It needs
linking against libgcc.a for various floating point TFmode
routines. The result runs.
tccgen.c:
- fix ldouble asm hack
- fix a VLA problem on Win64 (also x86_64-gen.c)
- patch_type(): make sure that no symbol ever changes
from global to static
tcc.c:
- tcc -vv: print libtcc1.a path also on win32
tccpe.c, tcctools.c:
- use unix LF mode to for .def output files (that is for
creating reproducible output trees)
Makefile:
- suppress some warnings when makeinfo is missing
- call 'which install' only on win32
tests/Makefile:
- change PATH only on WINNT systems (i.e. not if cross-compiling
on linux for win32)
- asm-c-connect.test: slim output and do diff
tccrun.c tccpe.c *-link.c:
- integrate former 'pe_relocate_rva()' into normal relocation
This also fixes linkage of the unwind data on WIN64 for -run
(reported by Janus Lynggaard Thorborg)
tccasm.c, tests/tcctest.c:
- fix dot (sym_index of -1 crashed in put_elf_reloc)
- massage .set a bit (see test)
other:
- #define SECTION_ABS removed
- ST_DATA Section *strtab_section: removed
- put_extern_sym2(): take int section number
Conflicts:
tccelf.c
tccpe.c
Conflicts:
tccelf.c
local symbols can be resolved statically, they don't have to be
done dynamically, so this is a slight speedup at load time for
produced executables and shared libs. The musl libc also rejects
any STB_LOCAL symbols for dynamic symbol resolution, so there it
also fixes use of shared libs created by tcc.
The O(xxx) stuff in i386-asm.c had me scratching my head. Extracting
the macro and trying it out in a separate program doesn't give
me any warnings, so I'm confused about what could be going on there.
Any cast will make things happy. I used a uint64_t to catch actual
cases of overflow, which will still cause a -Wconstant-conversion
warning.
Signed-off-by: Andrei Warkentin <andrey.warkentin@gmail.com>
This target has _32 and _32S relocs (the latter being for signed
32 bit entities). All instruction displacements have to use
the 32S variants. Normal references like
.long s
normally would use the _32 variant. For normal executables this
doesn't matter. For shared libraries neither (which use PC-relative
relocs). But it matters for things like the kernel that are linked
to high addresses (signed ones). There the GNU linker would error
out on overflow for the _32 variant.
To keep life simple we simply switch from _32 to _32S altogether.
Strictly speaking it's still wrong, but in practice using _32 is
more often wrong than using _32S ;)
- generate and use SYM@PLT for plt addresses
- get rid of patch_dynsym_undef hack (no idea what it did on FreeBSD)
- use sym_attrs instead of symtab_to_dynsym
- special case for function pointers into .so on i386
- libtcc_test: test tcc_add_symbol with data object
- move target specicic code to *-link.c files
- add R_XXX_RELATIVE (needed for PE)
MSVC does not support array designator so cannot compile source using
relocs_info. This commit replace the relocs_info array into a set of
functions, each returning the value given by a given field of the struct
reloc_info.
Last use for pltoff_addend field of relocs_info array was removed in
commit 25927df3b7. It is now useless so
this commit removes it and all initialization related to it.
i386 target does not have PC relative loads. Its ABI therefore require
ebx register to points to the GOT when executing a PLT entry. This means
that PLT entry cannot be used transparently, the compiler needs to
expect execution of a PLT entry to be able to use one, that is a PLT
entry should only be created if the relocation explicitely asks for it
(eg. R_386_PLT32).
This patch creates a new target macro PCRELATIVE_DLLPLT to indicate
whether a target can do a PC relative load in PLT entry when building a
dynamic library. Executable do not normally pose a problem because they
are loaded at a fixed address and thus the absolute address of GOT can
be used.
Note that in such a case, if the compiler does not use a PLT aware
relocation for external access then the code relocation will fall on the
dynamic loader since there is no PLT entry to relocate too.
C standard specifies that array should be declared with a non null size
or with * for standard array. Declaration of relocs_info in tcc.h was
not respecting this rule. This commit add a R_NUM macro that maps to the
R_<ARCH>_NUM macros and declare relocs_info using it. This commit also
moves all linker-related macros from <arch>-gen.c files to <arch>-link.c
ones.
Static relocation of functions in dynamic libraries must use the PLT
entry as the target. Before this commit, it used to be done in 2 parts
for ARM, with the offset of the PLT entry from the beginning of the PLT
being put in the relocated place in build_got_entries () and then the
address of the PLT being added in relocate_section.
This led to code dealing with reading the offset of a bl instruction in
build_got_entries. Furthermore, the addition of the address of the start
of the PLT was done based on the relocation type which does not convey
whether a PLT entry should be used to reach the symbol.
This commit moves the decision to use the PLT as the target in
relocate_section, therefore having the instruction aware code contained
to the target-specific bit of that function (in <target>-link.c).
Note that relocate_syms is *not* the right place to do this because two
different relocations for the same symbol can make different decision.
This is the case in tcc -run mode where the static and dynamic
relocation are done by tcc.
Storing the PLT entry address in the symbol's st_value field and relying
on the specific relocation type being used for dynamic relocation would
work but the PLT entry address would then appear in the static symbol
table (symtab). This would also make the static symbol table entry
differ from the dynamic symbol table entry.
