From 4810d96f03be4d3820563e3c6bf13dfc0627f205 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 3 Dec 2018 08:43:17 -0600 Subject: [PATCH] tcg/i386: Assume 32-bit values are zero-extended We now have an invariant that all TCG_TYPE_I32 values are zero-extended, which means that we do not need to extend them again during qemu_ld/st, either explicitly via a separate tcg_out_ext32u or implicitly via P_ADDR32. Reviewed-by: Emilio G. Cota Signed-off-by: Richard Henderson --- tcg/i386/tcg-target.inc.c | 103 ++++++++++++++++++---------------------------- 1 file changed, 40 insertions(+), 63 deletions(-) diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c index fe864e9ef9..f7b548545a 100644 --- a/tcg/i386/tcg-target.inc.c +++ b/tcg/i386/tcg-target.inc.c @@ -309,13 +309,11 @@ static inline int tcg_target_const_match(tcg_target_long val, TCGType type, #define P_EXT38 0x200 /* 0x0f 0x38 opcode prefix */ #define P_DATA16 0x400 /* 0x66 opcode prefix */ #if TCG_TARGET_REG_BITS == 64 -# define P_ADDR32 0x800 /* 0x67 opcode prefix */ # define P_REXW 0x1000 /* Set REX.W = 1 */ # define P_REXB_R 0x2000 /* REG field as byte register */ # define P_REXB_RM 0x4000 /* R/M field as byte register */ # define P_GS 0x8000 /* gs segment override */ #else -# define P_ADDR32 0 # define P_REXW 0 # define P_REXB_R 0 # define P_REXB_RM 0 @@ -528,9 +526,6 @@ static void tcg_out_opc(TCGContext *s, int opc, int r, int rm, int x) tcg_debug_assert((opc & P_REXW) == 0); tcg_out8(s, 0x66); } - if (opc & P_ADDR32) { - tcg_out8(s, 0x67); - } if (opc & P_SIMDF3) { tcg_out8(s, 0xf3); } else if (opc & P_SIMDF2) { @@ -1659,11 +1654,7 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi, tcg_out_modrm_offset(s, OPC_CMP_GvEv + trexw, r1, r0, 0); /* Prepare for both the fast path add of the tlb addend, and the slow - path function argument setup. There are two cases worth note: - For 32-bit guest and x86_64 host, MOVL zero-extends the guest address - before the fastpath ADDQ below. For 64-bit guest and x32 host, MOVQ - copies the entire guest address for the slow path, while truncation - for the 32-bit host happens with the fastpath ADDL below. */ + path function argument setup. */ tcg_out_mov(s, ttype, r1, addrlo); /* jne slow_path */ @@ -2022,41 +2013,31 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, bool is64) #else { int32_t offset = guest_base; - TCGReg base = addrlo; int index = -1; int seg = 0; - /* For a 32-bit guest, the high 32 bits may contain garbage. - We can do this with the ADDR32 prefix if we're not using - a guest base, or when using segmentation. Otherwise we - need to zero-extend manually. */ + /* + * Recall we store 32-bit values zero-extended. No need for + * further manual extension or an addr32 (0x67) prefix. + */ if (guest_base == 0 || guest_base_flags) { seg = guest_base_flags; offset = 0; - if (TCG_TARGET_REG_BITS > TARGET_LONG_BITS) { - seg |= P_ADDR32; - } - } else if (TCG_TARGET_REG_BITS == 64) { - if (TARGET_LONG_BITS == 32) { - tcg_out_ext32u(s, TCG_REG_L0, base); - base = TCG_REG_L0; - } - if (offset != guest_base) { - tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_L1, guest_base); - index = TCG_REG_L1; - offset = 0; - } + } else if (TCG_TARGET_REG_BITS == 64 && offset != guest_base) { + tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_L1, guest_base); + index = TCG_REG_L1; + offset = 0; } tcg_out_qemu_ld_direct(s, datalo, datahi, - base, index, offset, seg, is64, opc); + addrlo, index, offset, seg, is64, opc); } #endif } static void tcg_out_qemu_st_direct(TCGContext *s, TCGReg datalo, TCGReg datahi, - TCGReg base, intptr_t ofs, int seg, - TCGMemOp memop) + TCGReg base, int index, intptr_t ofs, + int seg, TCGMemOp memop) { /* ??? Ideally we wouldn't need a scratch register. For user-only, we could perform the bswap twice to restore the original value @@ -2080,8 +2061,8 @@ static void tcg_out_qemu_st_direct(TCGContext *s, TCGReg datalo, TCGReg datahi, tcg_out_mov(s, TCG_TYPE_I32, scratch, datalo); datalo = scratch; } - tcg_out_modrm_offset(s, OPC_MOVB_EvGv + P_REXB_R + seg, - datalo, base, ofs); + tcg_out_modrm_sib_offset(s, OPC_MOVB_EvGv + P_REXB_R + seg, + datalo, base, index, 0, ofs); break; case MO_16: if (bswap) { @@ -2089,7 +2070,8 @@ static void tcg_out_qemu_st_direct(TCGContext *s, TCGReg datalo, TCGReg datahi, tcg_out_rolw_8(s, scratch); datalo = scratch; } - tcg_out_modrm_offset(s, movop + P_DATA16 + seg, datalo, base, ofs); + tcg_out_modrm_sib_offset(s, movop + P_DATA16 + seg, datalo, + base, index, 0, ofs); break; case MO_32: if (bswap) { @@ -2097,7 +2079,7 @@ static void tcg_out_qemu_st_direct(TCGContext *s, TCGReg datalo, TCGReg datahi, tcg_out_bswap32(s, scratch); datalo = scratch; } - tcg_out_modrm_offset(s, movop + seg, datalo, base, ofs); + tcg_out_modrm_sib_offset(s, movop + seg, datalo, base, index, 0, ofs); break; case MO_64: if (TCG_TARGET_REG_BITS == 64) { @@ -2106,22 +2088,27 @@ static void tcg_out_qemu_st_direct(TCGContext *s, TCGReg datalo, TCGReg datahi, tcg_out_bswap64(s, scratch); datalo = scratch; } - tcg_out_modrm_offset(s, movop + P_REXW + seg, datalo, base, ofs); + tcg_out_modrm_sib_offset(s, movop + P_REXW + seg, datalo, + base, index, 0, ofs); } else if (bswap) { tcg_out_mov(s, TCG_TYPE_I32, scratch, datahi); tcg_out_bswap32(s, scratch); - tcg_out_modrm_offset(s, OPC_MOVL_EvGv + seg, scratch, base, ofs); + tcg_out_modrm_sib_offset(s, OPC_MOVL_EvGv + seg, scratch, + base, index, 0, ofs); tcg_out_mov(s, TCG_TYPE_I32, scratch, datalo); tcg_out_bswap32(s, scratch); - tcg_out_modrm_offset(s, OPC_MOVL_EvGv + seg, scratch, base, ofs+4); + tcg_out_modrm_sib_offset(s, OPC_MOVL_EvGv + seg, scratch, + base, index, 0, ofs + 4); } else { if (real_bswap) { int t = datalo; datalo = datahi; datahi = t; } - tcg_out_modrm_offset(s, movop + seg, datalo, base, ofs); - tcg_out_modrm_offset(s, movop + seg, datahi, base, ofs+4); + tcg_out_modrm_sib_offset(s, movop + seg, datalo, + base, index, 0, ofs); + tcg_out_modrm_sib_offset(s, movop + seg, datahi, + base, index, 0, ofs + 4); } break; default: @@ -2154,7 +2141,7 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, bool is64) label_ptr, offsetof(CPUTLBEntry, addr_write)); /* TLB Hit. */ - tcg_out_qemu_st_direct(s, datalo, datahi, TCG_REG_L1, 0, 0, opc); + tcg_out_qemu_st_direct(s, datalo, datahi, TCG_REG_L1, -1, 0, 0, opc); /* Record the current context of a store into ldst label */ add_qemu_ldst_label(s, false, is64, oi, datalo, datahi, addrlo, addrhi, @@ -2162,35 +2149,25 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, bool is64) #else { int32_t offset = guest_base; - TCGReg base = addrlo; + int index = -1; int seg = 0; - /* See comment in tcg_out_qemu_ld re zero-extension of addrlo. */ + /* + * Recall we store 32-bit values zero-extended. No need for + * further manual extension or an addr32 (0x67) prefix. + */ if (guest_base == 0 || guest_base_flags) { seg = guest_base_flags; offset = 0; - if (TCG_TARGET_REG_BITS > TARGET_LONG_BITS) { - seg |= P_ADDR32; - } - } else if (TCG_TARGET_REG_BITS == 64) { - /* ??? Note that we can't use the same SIB addressing scheme - as for loads, since we require L0 free for bswap. */ - if (offset != guest_base) { - if (TARGET_LONG_BITS == 32) { - tcg_out_ext32u(s, TCG_REG_L0, base); - base = TCG_REG_L0; - } - tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_L1, guest_base); - tgen_arithr(s, ARITH_ADD + P_REXW, TCG_REG_L1, base); - base = TCG_REG_L1; - offset = 0; - } else if (TARGET_LONG_BITS == 32) { - tcg_out_ext32u(s, TCG_REG_L1, base); - base = TCG_REG_L1; - } + } else if (TCG_TARGET_REG_BITS == 64 && offset != guest_base) { + /* ??? Note that we require L0 free for bswap. */ + tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_L1, guest_base); + index = TCG_REG_L1; + offset = 0; } - tcg_out_qemu_st_direct(s, datalo, datahi, base, offset, seg, opc); + tcg_out_qemu_st_direct(s, datalo, datahi, + addrlo, index, offset, seg, opc); } #endif } -- 2.11.4.GIT