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tcg: Remove dh_alias indirection for dh_typecode

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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>
This commit is contained in:
Richard Henderson 2022-02-16 20:06:22 -05:00
parent 00483d3869
commit 8929906e21
5 changed files with 19 additions and 9 deletions
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3
target/i386/ops_sse_header.h
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@ -30,6 +30,9 @@
#define dh_ctype_Reg Reg *
#define dh_ctype_ZMMReg ZMMReg *
#define dh_ctype_MMXReg MMXReg *
#define dh_typecode_Reg dh_typecode_ptr
#define dh_typecode_ZMMReg dh_typecode_ptr
#define dh_typecode_MMXReg dh_typecode_ptr
DEF_HELPER_3(glue(psrlw, SUFFIX), void, env, Reg, Reg)
DEF_HELPER_3(glue(psraw, SUFFIX), void, env, Reg, Reg)