I think this code only affects the ARM EABI target, and only when
returning small structures that might be unaligned. However, it was both
leaking vstack entries and failing to achieve what I think is its
purpose, to ensure the sret argument would be aligned properly. Both
issues fixed.
This patch disables the optimization of saving stack pointers lazily,
which didn't fully take into account that control flow might not reach
the stack-saving instructions. I've decided to leave in the extra calls
to vla_sp_save() in case anyone wants to restore this optimization.
Tests added and enabled.
There are two remaining bugs: VLA variables can be modified, and jumping
into the scope of a declared VLA will cause a segfault rather than a
compiler error. Both of these do not affect correct C code, but should
be fixed at some point. Once VLA variables have been made properly
immutable, we can share them with the saved stack pointer and save stack
and instructions.
The old code assumed that if an argument doesn't fit into the available
registers, none of the subsequent arguments do, either. But that's
wrong: passing 7 doubles, then a two-double struct, then another double
should generate code that passes the 9th argument in the 8th register
and the two-double struct on the stack. We now do so.
However, this patch does not yet fix the function calling code to do the
right thing in the same case.
The comment suggests this was meant to detect unions, but in fact it
compared f->c, the union/struct size, against f->next->c, the first
element's offset.
This affected only zero-length structs/unions with a first (zero-length)
element, as in this code:
struct u2 {
};
struct u {
struct u2 u2;
} u;
struct u f(struct u x)
{
return x;
}
However, such structures turned out to be broken anyway, as code like this
was generated for the above f:
0000000000000000 <f>:
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 48 81 ec 10 00 00 00 sub $0x10,%rsp
b: 66 0f d6 45 f8 movq %xmm0,-0x8(%rbp)
10: 66 0f 6e 45 f8 movd -0x8(%rbp),%xmm0
15: e9 00 00 00 00 jmpq 1a <f+0x1a>
1a: c9 leaveq
1b: c3 retq
With the x86_64 Linux ELF ABI, we're currently failing two of these
three tests, which have been disabled for now. The problem is mixed
structures such as struct { double x; char c; }, which the x86_64 ABI
specifies are to be passed/returned in one integer register and one SSE
register; our current approach, marking the structure as VT_QLONG or
VT_QFLOAT, fails in this case.
(It's possible to fix this by getting rid of VT_QLONG and VT_QFLOAT
entirely as at https://github.com/pipcet/tinycc, but the changes aren't
properly isolated at present. Anyway, there might be a less disruptive
fix.)
- pop_macro incorrect with initially undefined macro
- horrible implementation (tcc_open_bf)
- crashes eventually (abuse of Sym->prev_tok)
- the (unrelated) asm_label part is the opposite of a fix
(Despite of its name this variable has nothing to do with
the built-in assembler)
This reverts commit 0c8447db79.
I ran into an issue playing with tinycc, and tracked it down to a rather
weird assumption in the function calling code. This breaks only when
varargs and float/double arguments are combined, I think, and only when
calling GCC-generated (or non-TinyCC, at least) code. The problem is we
sometimes generate code like this:
804a468: 4c 89 d9 mov %r11,%rcx
804a46b: b8 01 00 00 00 mov $0x1,%eax
804a470: 48 8b 45 c0 mov -0x40(%rbp),%rax
804a474: 4c 8b 18 mov (%rax),%r11
804a477: 41 ff d3 callq *%r11
for a function call. Note how $eax is first set to the correct value,
then clobbered when we try to load the function pointer into R11. With
the patch, the code generated is:
804a468: 4c 89 d9 mov %r11,%rcx
804a46b: b8 01 00 00 00 mov $0x1,%eax
804a470: 4c 8b 5d c0 mov -0x40(%rbp),%r11
804a474: 4d 8b 1b mov (%r11),%r11
804a477: 41 ff d3 callq *%r11
which is correct.
This becomes an issue when get_reg(RC_INT) is modified not always to
return %rax after a save_regs(0), because then another register (%ecx,
say) is clobbered, and the function passed an invalid argument.
A rather convoluted test case that generates the above code is
included. Please note that the test will not cause a failure because
TinyCC code ignores the %rax argument, but it will cause incorrect
behavior when combined with GCC code, which might wrongly fail to save
XMM registers and cause data corruption.
Verify an immediate value fits into 32 bits before jumping to it/calling
it with a 32-bit immediate operand. Without this fix, code along the
lines of
((int (*)(const char *, ...))140244834372944LL)("hi\n");
will fail mysteriously, even if that decimal constant is the correct
address for printf.
See https://github.com/pipcet/tinycc/tree/bugfix-1
* give warning if pragma is unknown for tcc
* don't free asm_label in sym_free(),
it's a job of the asm_free_labels().
The above pragmas are used in the mingw headers.
Thise pragmas are implemented in gcc-4.5+ and current
clang.
Commit 5ce2154c ("-fdollar-in-identifiers addon", 20-04-2015) forgot
to include the test files from Daniel's patch.
Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Prior to this commit TinyCC was exporting symbols defined in programs
only when they resolve an undefined symbol of a library. However, the
expected behavior (see --export-dynamic in GNU ld manpage) is that all
symbols used by libraries and defined by a program should be exported in
dynsym section. This is because symbol resolution search first in
program and then in libraries, thus allowing program symbol to interpose
symbol defined in a library.
Usage example: tcc -xc ex5.cgi
From a gcc docs:
You can specify the input language explicitly with the -x option:
-x language
Specify explicitly the language for the following input files
(rather than letting the compiler choose a default based on the file
name suffix). This option applies to all following input files until
the next -x option. Possible values for language are:
c c-header c-cpp-output
c++ c++-header c++-cpp-output
objective-c objective-c-header objective-c-cpp-output
objective-c++ objective-c++-header objective-c++-cpp-output
assembler assembler-with-cpp
ada
f77 f77-cpp-input f95 f95-cpp-input
java
-x none
Turn off any specification of a language, so that subsequent files
are handled according to their file name suffixes (as they are if -x
has not been used at all)
library Cello: http://libcello.org/ which uses `$` and several
variations of as macros.
There is also RayLanguage which also uses it as a macro for a kind of
ObjC style message passing: https://github.com/kojiba/RayLanguage
This is a patch from Daniel Holden.
* define __bound_init as external_global_sym insteed of the compiling
a tiny program
* remove warning about buf[] when CONFIG_TCC_BCHECK is not defined
This is for a case when no '{' is used in the initialization code.
An option name is -fold-struct-init-code. A linux 2.4.26 can't
find initrd when compiled with a new algorithm.
Lets assume that in *.S files a preprocessor directive
follow '#' char w/o spaces between. Otherwise there is
too many problems with the content of the comments.
* tell a right line number in error message
if a #line directive is wrong
* don't print an error message if we preprocess a .S file
and #line directive is wrong. This is the case of
the
# 4026 bytes
comment in *.S file.
* preprocess_skip: skip a line with
if (parse_flags & PARSE_FLAG_ASM_COMMENTS)
p = parse_line_comment(p);
if line starts with # and a preprocessor command not found.
A test program:
#if defined(CONFIG_EDD) || defined(CONFIG_EDD_MODULE)
# This repeats until either a device doesn't exist, or until
#endif
* remove a second definition of the TOK_FLAG_* and PARSE_FLAG_*
from the tccpp.c
* define targetos=Windows when --enable-tcc32-mingw, --enable-cygwin, ...
* use TARGETOS insteed HOST_OS when selecting PROGS
* use "$(tccdir)" insteed $(tccdir) on install (spaces in path)
* install tcc.exe too
* produce bcheck.o when cross-compiling too (lib/Makefile)
* force bcheck.o linking by compiling inside tcc_set_output_type()
a dummy program with local array. Otherwise bcheck.o may be not linked.
* replace %xz format specifier with %p in bcheck (don't supported on
Windows)
* call a __bound_init when __bound_ptr_add, __bound_ptr_indir,
__bound_new_region, __bound_delete_region called.
This is because a __bound_init inside ".init" section is not called
on Windows for unknown reason.
* print on stderr a message when an illegal pointer is returned:
there is no segmentation violation on Windows for a program
compiled with "tcc -b"
* remove "C:" subdir on clean if $HOST_OS = "Linux"
* default CFLAGS="-Wall -g -O0" insteed CFLAGS="-Wall -g -O2"
to speed up compilation and more precise debugging.
tcc w/o -g option generate an executable file which format
is not recognized by binutils. It is like stripped one but
binutils don't think so. Solution: generate not stripped
file which can be correctly stripped by external utils.
may be there is a need to handle a -s option and call
a sstrip/strip program to do a job.
------------ libtest ------------
./libtcc_test lib_path=..
<string>:11: warning: implicit declaration of function 'printf'
<string>:13: warning: implicit declaration of function 'add'
------------ test3 ------------
tcctest.c:1982: warning: implicit declaration of function 'putchar'
tcctest.c:2133: warning: implicit declaration of function 'strlen'
- a warning: unnamed struct/union that defines no instances
- allow a nested named struct declaration w/o identifier
only when option -fms-extensions is used
