qemu/include/exec/helper-head.h
Richard Henderson 8929906e21 tcg: Remove dh_alias indirection for dh_typecode
The dh_alias redirect is intended to handle TCG types as distinguished
from C types.  TCG does not distinguish signed int from unsigned int,
because they are the same size.  However, we need to retain this
distinction for dh_typecode, lest we fail to extend abi types properly
for the host call parameters.

This bug was detected when running the 'arm' emulator on an s390
system. The s390 uses TCG_TARGET_EXTEND_ARGS which triggers code
in tcg_gen_callN to extend 32 bit values to 64 bits; the incorrect
sign data in the typemask for each argument caused the values to be
extended as unsigned values.

This simple program exhibits the problem:

	static volatile int num = -9;
	static volatile int den = -5;
	int main(void)
	{
		int quo = num / den;
		printf("num %d den %d quo %d\n", num, den, quo);
		exit(0);
	}

When run on the broken qemu, this results in:

	num -9 den -5 quo 0

The correct result is:

	num -9 den -5 quo 1

Fixes: 7319d83a73 ("tcg: Combine dh_is_64bit and dh_is_signed to dh_typecode")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/876
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reported-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Tested-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Tested-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2022-02-28 08:04:06 -10:00

139 lines
4.6 KiB
C

/* Helper file for declaring TCG helper functions.
Used by other helper files.
Targets should use DEF_HELPER_N and DEF_HELPER_FLAGS_N to declare helper
functions. Names should be specified without the helper_ prefix, and
the return and argument types specified. 3 basic types are understood
(i32, i64 and ptr). Additional aliases are provided for convenience and
to match the types used by the C helper implementation.
The target helper.h should be included in all files that use/define
helper functions. THis will ensure that function prototypes are
consistent. In addition it should be included an extra two times for
helper.c, defining:
GEN_HELPER 1 to produce op generation functions (gen_helper_*)
GEN_HELPER 2 to do runtime registration helper functions.
*/
#ifndef EXEC_HELPER_HEAD_H
#define EXEC_HELPER_HEAD_H
#define HELPER(name) glue(helper_, name)
/* Some types that make sense in C, but not for TCG. */
#define dh_alias_i32 i32
#define dh_alias_s32 i32
#define dh_alias_int i32
#define dh_alias_i64 i64
#define dh_alias_s64 i64
#define dh_alias_f16 i32
#define dh_alias_f32 i32
#define dh_alias_f64 i64
#define dh_alias_ptr ptr
#define dh_alias_cptr ptr
#define dh_alias_void void
#define dh_alias_noreturn noreturn
#define dh_alias(t) glue(dh_alias_, t)
#define dh_ctype_i32 uint32_t
#define dh_ctype_s32 int32_t
#define dh_ctype_int int
#define dh_ctype_i64 uint64_t
#define dh_ctype_s64 int64_t
#define dh_ctype_f16 uint32_t
#define dh_ctype_f32 float32
#define dh_ctype_f64 float64
#define dh_ctype_ptr void *
#define dh_ctype_cptr const void *
#define dh_ctype_void void
#define dh_ctype_noreturn void QEMU_NORETURN
#define dh_ctype(t) dh_ctype_##t
#ifdef NEED_CPU_H
# ifdef TARGET_LONG_BITS
# if TARGET_LONG_BITS == 32
# define dh_alias_tl i32
# define dh_typecode_tl dh_typecode_i32
# else
# define dh_alias_tl i64
# define dh_typecode_tl dh_typecode_i64
# endif
# endif
# define dh_ctype_tl target_ulong
# define dh_alias_env ptr
# define dh_ctype_env CPUArchState *
# define dh_typecode_env dh_typecode_ptr
#endif
/* We can't use glue() here because it falls foul of C preprocessor
recursive expansion rules. */
#define dh_retvar_decl0_void void
#define dh_retvar_decl0_noreturn void
#define dh_retvar_decl0_i32 TCGv_i32 retval
#define dh_retvar_decl0_i64 TCGv_i64 retval
#define dh_retvar_decl0_ptr TCGv_ptr retval
#define dh_retvar_decl0(t) glue(dh_retvar_decl0_, dh_alias(t))
#define dh_retvar_decl_void
#define dh_retvar_decl_noreturn
#define dh_retvar_decl_i32 TCGv_i32 retval,
#define dh_retvar_decl_i64 TCGv_i64 retval,
#define dh_retvar_decl_ptr TCGv_ptr retval,
#define dh_retvar_decl(t) glue(dh_retvar_decl_, dh_alias(t))
#define dh_retvar_void NULL
#define dh_retvar_noreturn NULL
#define dh_retvar_i32 tcgv_i32_temp(retval)
#define dh_retvar_i64 tcgv_i64_temp(retval)
#define dh_retvar_ptr tcgv_ptr_temp(retval)
#define dh_retvar(t) glue(dh_retvar_, dh_alias(t))
#define dh_typecode_void 0
#define dh_typecode_noreturn 0
#define dh_typecode_i32 2
#define dh_typecode_s32 3
#define dh_typecode_i64 4
#define dh_typecode_s64 5
#define dh_typecode_ptr 6
#define dh_typecode_int dh_typecode_s32
#define dh_typecode_f16 dh_typecode_i32
#define dh_typecode_f32 dh_typecode_i32
#define dh_typecode_f64 dh_typecode_i64
#define dh_typecode_cptr dh_typecode_ptr
#define dh_typecode(t) dh_typecode_##t
#define dh_callflag_i32 0
#define dh_callflag_i64 0
#define dh_callflag_ptr 0
#define dh_callflag_void 0
#define dh_callflag_noreturn TCG_CALL_NO_RETURN
#define dh_callflag(t) glue(dh_callflag_, dh_alias(t))
#define dh_typemask(t, n) (dh_typecode(t) << (n * 3))
#define dh_arg(t, n) \
glue(glue(tcgv_, dh_alias(t)), _temp)(glue(arg, n))
#define dh_arg_decl(t, n) glue(TCGv_, dh_alias(t)) glue(arg, n)
#define DEF_HELPER_0(name, ret) \
DEF_HELPER_FLAGS_0(name, 0, ret)
#define DEF_HELPER_1(name, ret, t1) \
DEF_HELPER_FLAGS_1(name, 0, ret, t1)
#define DEF_HELPER_2(name, ret, t1, t2) \
DEF_HELPER_FLAGS_2(name, 0, ret, t1, t2)
#define DEF_HELPER_3(name, ret, t1, t2, t3) \
DEF_HELPER_FLAGS_3(name, 0, ret, t1, t2, t3)
#define DEF_HELPER_4(name, ret, t1, t2, t3, t4) \
DEF_HELPER_FLAGS_4(name, 0, ret, t1, t2, t3, t4)
#define DEF_HELPER_5(name, ret, t1, t2, t3, t4, t5) \
DEF_HELPER_FLAGS_5(name, 0, ret, t1, t2, t3, t4, t5)
#define DEF_HELPER_6(name, ret, t1, t2, t3, t4, t5, t6) \
DEF_HELPER_FLAGS_6(name, 0, ret, t1, t2, t3, t4, t5, t6)
#define DEF_HELPER_7(name, ret, t1, t2, t3, t4, t5, t6, t7) \
DEF_HELPER_FLAGS_7(name, 0, ret, t1, t2, t3, t4, t5, t6, t7)
/* MAX_OPC_PARAM_IARGS must be set to n if last entry is DEF_HELPER_FLAGS_n. */
#endif /* EXEC_HELPER_HEAD_H */