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Fix the get_asm_string fail on i386 in another way

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the problem is that new debian GCC enabled -fPIC or -fPIE by
default, causing the mentioned compile error.
This commit is contained in:
Michael Matz 2019-12-17 17:54:54 +01:00
parent 43fb5a72e7
commit f150f93854
2 changed files with 19 additions and 7 deletions
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5
tests/Makefile
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@ -64,6 +64,11 @@ ifeq ($(ARCH),arm)
# of functions via bit masking comes out as 1. Just disable thumb. # of functions via bit masking comes out as 1. Just disable thumb.
test.ref: CFLAGS+=-marm test.ref: CFLAGS+=-marm
endif endif
ifeq ($(ARCH),i386)
# tcctest.c:get_asm_string uses a construct that is checked too strictly
# by GCC in 32bit mode when PIC is enabled.
test.ref: CFLAGS+=-fno-PIC -fno-PIE
endif
RUN_TCC = $(NATIVE_DEFINES) -run $(TOPSRC)/tcc.c $(TCCFLAGS) RUN_TCC = $(NATIVE_DEFINES) -run $(TOPSRC)/tcc.c $(TCCFLAGS)
DISAS = objdump -d DISAS = objdump -d

21
tests/tcctest.c
View File

@ -3320,12 +3320,20 @@ void override_func2 (void)
extern int bug_table[] __attribute__((section("__bug_table"))); extern int bug_table[] __attribute__((section("__bug_table")));
char * get_asm_string (void) char * get_asm_string (void)
{ {
#ifdef __i386__ /* On i386 when -fPIC is enabled this would cause a compile error with GCC,
/* i386 is not currently tested because this code triggers a gcc the problem being the "i" constraint used with a symbolic operand
bug on some distributions. See resolving to a local label. That check is overly zealous as the code
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=946678 */ within the asm makes sure to use it only in PIC-possible contexts,
char *str = "(not tested)"; but all GCC versions behave like so. We arrange for PIC to be disabled
#else for compiling tcctest.c in the Makefile.
Additionally the usage of 'c' in "%c0" in the template is actually wrong,
as that would expect an operand that is a condition code. The operand
as is (a local label) is accepted by GCC in non-PIC mode, and on x86-64.
What the linux kernel really wanted is 'p' to disable the addition of '$'
to the printed operand (as in "$.LC0" where the template only wants the
bare operand ".LC0"). But the code below is what the linux kernel
happens to use and as such is the one we want to test. */
extern int some_symbol; extern int some_symbol;
asm volatile (".globl some_symbol\n" asm volatile (".globl some_symbol\n"
"jmp .+6\n" "jmp .+6\n"
@ -3340,7 +3348,6 @@ char * get_asm_string (void)
"2:\t.long 1b - 2b, %c0 - 2b\n" "2:\t.long 1b - 2b, %c0 - 2b\n"
".popsection\n" : : "i" ("A string")); ".popsection\n" : : "i" ("A string"));
char * str = ((char*)bug_table) + bug_table[1]; char * str = ((char*)bug_table) + bug_table[1];
#endif
return str; return str;
} }