target-arm: A64: Fix shifts into sign bit

Fix attempts to shift into the sign bit of an int, which is undefined
behaviour in C and warned about by the clang sanitizer.

Backports commit 1743d55c8b38bcee632cf6eb2de81131635bb3d2 from qemu
This commit is contained in:
Peter Maydell 2018-02-12 15:00:43 -05:00 committed by Lioncash
parent 8612f1d3e7
commit b95cba4677
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@ -1109,7 +1109,7 @@ static void disas_uncond_b_imm(DisasContext *s, uint32_t insn)
TCGContext *tcg_ctx = s->uc->tcg_ctx;
uint64_t addr = s->pc + sextract32(insn, 0, 26) * 4 - 4;
if (insn & (1 << 31)) {
if (insn & (1U << 31)) {
/* C5.6.26 BL Branch with link */
tcg_gen_movi_i64(tcg_ctx, cpu_reg(s, 30), s->pc);
}
@ -1308,7 +1308,7 @@ static void gen_get_nzcv(TCGContext *tcg_ctx, TCGv_i64 tcg_rt)
TCGv_i32 nzcv = tcg_temp_new_i32(tcg_ctx);
/* build bit 31, N */
tcg_gen_andi_i32(tcg_ctx, nzcv, tcg_ctx->cpu_NF, (1 << 31));
tcg_gen_andi_i32(tcg_ctx, nzcv, tcg_ctx->cpu_NF, (1U << 31));
/* build bit 30, Z */
tcg_gen_setcondi_i32(tcg_ctx, TCG_COND_EQ, tmp, tcg_ctx->cpu_ZF, 0);
tcg_gen_deposit_i32(tcg_ctx, nzcv, nzcv, tmp, 30, 1);
@ -1333,7 +1333,7 @@ static void gen_set_nzcv(TCGContext *tcg_ctx, TCGv_i64 tcg_rt)
tcg_gen_extrl_i64_i32(tcg_ctx, nzcv, tcg_rt);
/* bit 31, N */
tcg_gen_andi_i32(tcg_ctx, tcg_ctx->cpu_NF, nzcv, (1 << 31));
tcg_gen_andi_i32(tcg_ctx, tcg_ctx->cpu_NF, nzcv, (1U << 31));
/* bit 30, Z */
tcg_gen_andi_i32(tcg_ctx, tcg_ctx->cpu_ZF, nzcv, (1 << 30));
tcg_gen_setcondi_i32(tcg_ctx, TCG_COND_EQ, tcg_ctx->cpu_ZF, tcg_ctx->cpu_ZF, 0);