A more automatic approach to code suppression (aka. nocode_wanted)
The simple rules are:
- Clear 'nocode_wanted' at (im/explicit) label IF it was used
- Set 'nocode_wanted' after unconditional jumps
Also in order to test this then I did add the "function might
return no value" warning, and then to make that work again I
did add the __attribute__((noreturn)).
Also moved the look ahead label check into the type parser
to gain a little speed.
Example:
int a = 1;
void f(void)
{
int a = 2;
{
extern int a; // = 1 !!
....
To get this (more) correctly there is a new function to copy
syms between local to global stacks.
Also, this patch changes the meaning of VT_EXTERN back
to the simpler and IMO more useful notion of
DECLARED but not (yet) DEFINED.
and that for both variables and functions. That is, VT_EXTERN
in tcc doesn't have to do with the keyword 'extern' necessarily.
Also this patch does allow
int x[];
as alias for
extern int x[];
(as do gcc and msvc)
GCC wouldn't be able to implement this either (due to the separate
phases of compilation and assembly). We could allow it but it
makes not much sense and actively can confuse broken code into
segfaulting TCC. At least we can warn.
Warning exposes a problem in tcctest, and fixing that gives us
an opportunity to also test .pushsection/.popsection and .previous
directive support.
the real difference is in decl0 where we can use external_sym
just fine also for function definitions, we don't have to use
external_global_sym. Setting VT_EXTERN in external_sym isn't
necessary either (the type will have it set if necessary).
The rest is tidying: removing unused arguments and moving
some code around.
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
for this we have to create also asm symbols as VT_STATIC initially
except if there's an indication that it should be global (.globl
or undefined at end of unit). For this to work we need to
be able to globalize symbols after they were local and enter them
into the ELF hash tables, and also adjust the symbols that were
potentially already used in relocs when they were still local.
The easiest is to do a proper symbol resolution step also in multi-file
mode, for regular symbols (the non-dynamic ones, i.e. not from shared
libs).
* removed asm_label stack
* removed asm_free_labels() post-processing
* using "impossible C type" for asm labels (VT_ASM)
* tccgen.c:update_storage(): use it to refresh symbol attributes
* tccelf.c:find_elf_sym(): ignore STB_LOCAL symbols
* tccgen.c:unary(): asm symbols are supposed to be undeclared in C
See testcase (from grischka). If the asm has no .globl,
but there's a (non-static) C definition the symbol should
be exported, even if the first reference comes from asm.
This makes the asm symbols use the same members as the C symbols
for global decls, e.g. using the ELF symbol to hold offset and
section. That allows us to use only one symbol table for C and
asm symbols and to get rid of hacks to synch between them.
We still need some special handling for symbols that come purely
from asm sources.
For tracking if asm symbols are connected with a C symbol,
and if asm symbols need to be global use new flags, instead of
reusing dllimport/dllexport, which would cause unrequested exported
entries on Windows.
This is a stop-gap until the C and asm symtable are unified.
See testcase. The C and asm symtab are still separate,
but integrated tighter: the asm labels are only synched at file
end, not after each asm snippet (this fixes references from one
to another asm block), the C and asm syms are synched both ways,
so defining things in asm and refering from C, or the other way
around works. In effect this model reflects what happens with
GCC better.
For this the asm labels aren't using the C label namespace anymore,
but their own, which increases the size of each TokenSym by a pointer.
while last change fixed one part of label behaviour (undefined ones
must be global) it again broke a different aspect (forward defs
without .globl must stay local). This fixes both aspects.
That a label is local instead of global is difficult to test without
resorting to look at the symbol table or using two-file testcases,
so we do without. In essence the local/global-ness of symbols
should be the same between GAS and TCC for this input:
.globl glob1
glob1:
call glob1
.globl glob2
call glob2
glob2:
glob3:
.globl glob3
call glob3
glob4:
call glob4
.globl glob4
call glob5
.globl glob5
glob5:
call glob6
glob6:
.globl glob6
locl1:
call locl1
call locl2
locl2:
unref1:
unref2:
.globl unref2
.globl unref3
unref3:
call undef
fixes the problem in the testcase. A symbolic reference
from asm, which remains undefined at the end of processing is
always a global reference, not a static (STB_LOCAL) one.
This also affected the linux kernel.
win32/Makefile ("for cygwin") removed
- On cygwin, the normal ./configure && make can be used with either
cygwin's "GCC for Win32 Toolchain"
./configure --cross-prefix=i686-w64-mingw32-
or with an existing tcc:
./configure --cc=<old-tccdir>/tcc.exe
tcctest.c:
- exclude test_high_clobbers() on _WIN64 (does not work)
tests2/95_bitfield.c:
- use 'signed char' for ARM (where default 'char' is unsigned)
tests:
- remove -I "expr" diff option to allow tests with
busybox-diff.
libtcc.c, tcc.c:
- removed -iwithprefix option. It is supposed to be
combined with -iprefix which we don't have either.
tccgen.c:
- fix assignments and return of 'void', as in
void f() {
void *p, *q;
*p = *q:
return *p;
}
This appears to be allowed but should do nothing.
tcc.h, libtcc.c, tccpp.c:
- Revert "Introduce VIP sysinclude paths which are always searched first"
This reverts commit 1d5e386b0a.
The patch was giving tcc's system includes priority over -I which
is not how it should be.
tccelf.c:
- add DT_TEXTREL tag only if text relocations are actually
used (which is likely not the case on x86_64)
- prepare_dynamic_rel(): avoid relocation of unresolved
(weak) symbols
tccrun.c:
- for HAVE_SELINUX, use two mappings to the same (real) file.
(it was so once except the RX mapping wasn't used at all).
tccpe.c:
- fix relocation constant used for x86_64 (by Andrei E. Warentin)
- #ifndef _WIN32 do "chmod 755 ..." to get runnable exes on cygwin.
tccasm.c:
- keep forward asm labels static, otherwise they will endup
in dynsym eventually.
configure, Makefile:
- mingw32: respect ./configure options --bindir --docdir --libdir
- allow overriding tcc when building libtcc1.a and libtcc.def with
make XTCC=<tcc program to use>
- use $(wildcard ...) for install to allow installing just
a cross compiler for example
make cross-arm
make install
- use name <target>-libtcc1.a
build-tcc.bat:
- add options: -clean, -b bindir
* -dt now with lowercase t
* test snippets now separated by real preprocessor statements
which is valid C also for other compilers
#if defined test_xxx
< test snippet x >
#elif defined test_yyy
< test snippet y >
#elif ...
#endif
* simpler implementation, behaves like -run if no 'test_...' macros
are seen, works with -E too
* for demonstration I combined some of the small tests for errors
and warnings (56..63,74) in "60_errors_and_warnings.c"
Also:
* libtcc.c:
put tcc_preprocess() and tcc_assemble() under the setjmp clause
to let them return to caller after errors. This is for -dt -E.
* tccgen.c:
- get rid of save/restore_parse_state(), macro_ptr is saved
by begin_macro anyway, now line_num too.
- use expr_eq for parsing _Generic's controlling_type
- set nocode_wanted with const_wanted. too, This is to keep
VT_JMP on vtop when parsing preprocessor expressions.
* tccpp.c: tcc -E: suppress trailing whitespace from lines with
comments (that -E removes) such as
NO_GOTPLT_ENTRY,\t /* never generate ... */
tcc.h:
* cleanup struct 'Sym'
* include some 'Attributes' into 'Sym'
* in turn get rid of VT_IM/EXPORT, VT_WEAK
* re-number VT_XXX flags
* replace some 'long' function args by 'int'
tccgen.c:
* refactor parse_btype()
- configure:
- add --config-uClibc,-musl switch and suggest to use
it if uClibc/musl is detected
- make warning options magic clang compatible
- simplify (use $confvars instead of individual options)
- Revert "Remove some unused-parameter lint"
7443db0d5f
rather use -Wno-unused-parameter (or just not -Wextra)
- #ifdef functions that are unused on some targets
- tccgen.c: use PTR_SIZE==8 instead of (X86_64 || ARM64)
- tccpe.c: fix some warnings
- integrate dummy arm-asm better
Mark TCCState parameter as unused in tcc_undefine_symbol(), tcc_add_symbol(),
tcc_print_stats(), asm_get_local_label_name(), use_section1(), tccpp_delete(),
tcc_tool_ar(), tcc_tool_impdef(), and tcc_tool_cross().
Also mark it unused in tcc_add_bcheck() unless CONFIG_TCC_BCHECK.
Remove it entirely in ld_next().
- configure/Makefiles: minor adjustments
- build-tcc.bat: add -static to gcc options
(avoids libgcc_s*.dll dependency with some mingw versions)
- tccpe.c/tcctools.c: eliminate MAX_PATH
(not available for cross compilers)
- tccasm.c: use uint64_t/strtoull in unary()
(unsigned long sometimes is only uint32_t, as always on windows)
- tccgen.c: Revert (f077d16c) "tccgen: gen_cast: cast FLOAT to DOUBLE"
Was a rather experimental, tentative commit, not really necessary
and somewhat ugly too.
- cleanup recent osx support:
- Makefile/libtcc.c: cleanup copy&paste code
- tccpp.c: restore deleted function
Forgot about it. It allows to compile several
sources (and other .o's) to one single .o file;
tcc -r -o all.o f1.c f2.c f3.S o4.o ...
Also:
- option -fold-struct-init-code removed, no effect anymore
- (tcc_)set_environment() moved to tcc.c
- win32/lib/(win)crt1 minor fix & add dependency
- debug line output for asm (tcc -c -g xxx.S) enabled
- configure/Makefiles: x86-64 -> x86_64 changes
- README: cleanup
usage:
tcc -ar [rcsv] lib files...
tcc -impdef lib.dll [-v] [-o lib.def]
also:
- support more files with -c: tcc -c f1.c f2.c ...
- fix a bug which caused tcc f1.c f2.S to produce no asm
- allow tcc -ar @listfile too
- change prototype: _void_ tcc_set_options(...)
- apply -Wl,-whole-archive when a librariy is given
as libxxx.a also (not just for -lxxx)
- define_start: set above preprocess_start because now
preprocess_start is defining macros.
- free "cmd_include_files"
- free defines always (after error-longjmps)
- close all files (after error-longjmps)
- tccpe.c: free imports always
- libtcc.c: call tcc_memstats only after all states have
been deleted.
Some more subtle issues with code suppression:
- outputting asms but not their operand setup is broken
- but global asms must always be output
- statement expressions are transparent to code suppression
- vtop can't be transformed from VT_CMP/VT_JMP when nocode_wanted
Also remove .exe files from tests2 if they don't fail.
tccgen.c: remove any 'nocode_wanted' checks, except in
- greloca(), disables output elf symbols and relocs
- get_reg(), will return just the first suitable reg)
- save_regs(), will do nothing
Some minor adjustments were made where nocode_wanted is set.
xxx-gen.c: disable code output directly where it happens
in functions:
- g(), output disabled
- gjmp(), will do nothing
- gtst(), dto.
This happens when e.g. string constants (or other static data)
are passed as operands to inline asm as immediates. The produced
symbol ref wouldn't be found. So tighten the connection between
C and asm-local symbol table even more.
Our preprocessor throws away # line-comments in asm mode.
It did so also inside preprocessor directives, thereby
removing stringification. Parse defines in non-asm mode (but
retain '.' as identifier character inside macro definitions).
That, as well as "sym = expr", if expr contains symbols.
Slightly tricky because a definition from .set is overridable,
whereas proper definitions aren't.
This doesn't yet allow using this for override tricks from C
and global asm blocks because the symbol tables from C and asm
are separate.
But like GCC do warn about changes in signedness. The latter
leads to some changes in gen_assign_cast to not also warn about
unsigned* = int*
(where GCC warns, but only with extra warnings).
A 'P' template modifier should avoid adding a '$' to literal
arguments. Also accept the numbered r8+ registers in an inline
asm clobber list (ignoring them for now).
In particular subtracting a defined symbol from current section
makes the value PC relative, and .org accepts symbolic expressions
as well, if the symbol is from the current section.
The problem was with tcctest.c:
unsigned set;
__asm__("btsl %1,%0" : "=m"(set) : "Ir"(20) : "cc");
when with tcc compiled with the HAVE_SELINUX option, run with
tcc -run, it would use large addresses far beyond the 32bits
range when tcc did not use the pc-relative mode for accessing
'set' in global data memory. In fact the assembler did not
know about %rip at all.
Changes:
- memory operands use (%rax) not (%eax)
- conversion from VT_LLOCAL: use type VT_PTR
- support 'k' modifier
- support %rip register
- support X(%rip) pc-relative addresses
The test in tcctest.c is from Michael Matz.
- "utf8 in identifiers"
from 936819a1b9
- CValue: remove member str.data_allocated
- make tiny allocator private to tccpp
- allocate macro_stack objects on heap
because otherwise it could crash after error/setjmp
in preprocess_delete():end_macro()
- mov "TinyAlloc" defs to tccpp.c
- define_push: take int* str again
Fix it to actually be able to parse 64bit immediates (enlarge
operand value type). Then, generally there's no need for accepting
IM64 anywhere, except in the 0xba+r mov opcodes, so OP_IM is
unnecessary, as is OPT_IMNO64. Improve the generated code a bit
by preferring the 0xc7 opcode for im32->reg64, instead of the
im64->reg64 form (which we therefore hardcode).
A problem was in TOK_ASMDIR_text:
- sprintf(sname, ".%s", get_tok_str(tok1, NULL));
+ sprintf(sname, "%s", get_tok_str(tok1, NULL));
When tok1 is '.text', then sname is '..text'
When tccboot kernels compiles with
'Identifiers can start and/or', this kernel don't start.
It is hard to find what is wrong.
PS: there was no test for identifiers in *.S with '.'
