commit 798a4a5bfc491fef81cf968cd0039ad60f34366a Author: Richard Henderson Date: Fri Dec 18 13:01:30 2009 -0800 tcg-i386: Implement small forward branches. There are places, like brcond2, where we know that the destination of a forward branch will be within 127 bytes. Add the R_386_PC8 relocation type to support this. Add a flag to tcg_out_jxx and tcg_out_brcond* to enable it. Set the flag in the brcond2 label_next branches; pass along the input flag otherwise. Signed-off-by: Richard Henderson diff --git a/elf.h b/elf.h index 11674d7..c84c8ab 100644 --- a/elf.h +++ b/elf.h @@ -243,6 +243,8 @@ typedef struct { #define R_386_GOTOFF 9 #define R_386_GOTPC 10 #define R_386_NUM 11 +/* Not a dynamic reloc, so not included in R_386_NUM. Used in TCG. */ +#define R_386_PC8 23 #define R_MIPS_NONE 0 #define R_MIPS_16 1 diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c index 972b102..48c9bc8 100644 --- a/tcg/i386/tcg-target.c +++ b/tcg/i386/tcg-target.c @@ -61,6 +61,12 @@ static void patch_reloc(uint8_t *code_ptr, int type, case R_386_PC32: *(uint32_t *)code_ptr = value - (long)code_ptr; break; + case R_386_PC8: + value -= (long)code_ptr; + if (value != (int8_t)value) + tcg_abort(); + *(uint8_t *)code_ptr = value; + break; default: tcg_abort(); } @@ -305,7 +311,8 @@ static void tcg_out_addi(TCGContext *s, int reg, tcg_target_long val) tgen_arithi(s, ARITH_ADD, reg, val, 0); } -static void tcg_out_jxx(TCGContext *s, int opc, int label_index) +/* Use SMALL != 0 to force a short forward branch. */ +static void tcg_out_jxx(TCGContext *s, int opc, int label_index, int small) { int32_t val, val1; TCGLabel *l = &s->labels[label_index]; @@ -320,6 +327,8 @@ static void tcg_out_jxx(TCGContext *s, int opc, int label_index) tcg_out8(s, 0x70 + opc); tcg_out8(s, val1); } else { + if (small) + tcg_abort(); if (opc == -1) { tcg_out8(s, 0xe9); tcg_out32(s, val - 5); @@ -329,6 +338,14 @@ static void tcg_out_jxx(TCGContext *s, int opc, int label_index) tcg_out32(s, val - 6); } } + } else if (small) { + if (opc == -1) { + tcg_out8(s, 0xeb); + } else { + tcg_out8(s, 0x70 + opc); + } + tcg_out_reloc(s, s->code_ptr, R_386_PC8, label_index, -1); + s->code_ptr += 1; } else { if (opc == -1) { tcg_out8(s, 0xe9); @@ -343,7 +360,7 @@ static void tcg_out_jxx(TCGContext *s, int opc, int label_index) static void tcg_out_brcond(TCGContext *s, int cond, TCGArg arg1, TCGArg arg2, int const_arg2, - int label_index) + int label_index, int small) { if (const_arg2) { if (arg2 == 0) { @@ -355,64 +372,84 @@ static void tcg_out_brcond(TCGContext *s, int cond, } else { tcg_out_modrm(s, 0x01 | (ARITH_CMP << 3), arg2, arg1); } - tcg_out_jxx(s, tcg_cond_to_jcc[cond], label_index); + tcg_out_jxx(s, tcg_cond_to_jcc[cond], label_index, small); } /* XXX: we implement it at the target level to avoid having to handle cross basic blocks temporaries */ -static void tcg_out_brcond2(TCGContext *s, - const TCGArg *args, const int *const_args) +static void tcg_out_brcond2(TCGContext *s, const TCGArg *args, + const int *const_args, int small) { int label_next; label_next = gen_new_label(); switch(args[4]) { case TCG_COND_EQ: - tcg_out_brcond(s, TCG_COND_NE, args[0], args[2], const_args[2], label_next); - tcg_out_brcond(s, TCG_COND_EQ, args[1], args[3], const_args[3], args[5]); + tcg_out_brcond(s, TCG_COND_NE, args[0], args[2], const_args[2], + label_next, small); + tcg_out_brcond(s, TCG_COND_EQ, args[1], args[3], const_args[3], + args[5], small); break; case TCG_COND_NE: - tcg_out_brcond(s, TCG_COND_NE, args[0], args[2], const_args[2], args[5]); - tcg_out_brcond(s, TCG_COND_NE, args[1], args[3], const_args[3], args[5]); + tcg_out_brcond(s, TCG_COND_NE, args[0], args[2], const_args[2], + args[5], small); + tcg_out_brcond(s, TCG_COND_NE, args[1], args[3], const_args[3], + args[5], small); break; case TCG_COND_LT: - tcg_out_brcond(s, TCG_COND_LT, args[1], args[3], const_args[3], args[5]); - tcg_out_jxx(s, JCC_JNE, label_next); - tcg_out_brcond(s, TCG_COND_LTU, args[0], args[2], const_args[2], args[5]); + tcg_out_brcond(s, TCG_COND_LT, args[1], args[3], const_args[3], + args[5], small); + tcg_out_jxx(s, JCC_JNE, label_next, 1); + tcg_out_brcond(s, TCG_COND_LTU, args[0], args[2], const_args[2], + args[5], small); break; case TCG_COND_LE: - tcg_out_brcond(s, TCG_COND_LT, args[1], args[3], const_args[3], args[5]); - tcg_out_jxx(s, JCC_JNE, label_next); - tcg_out_brcond(s, TCG_COND_LEU, args[0], args[2], const_args[2], args[5]); + tcg_out_brcond(s, TCG_COND_LT, args[1], args[3], const_args[3], + args[5], small); + tcg_out_jxx(s, JCC_JNE, label_next, 1); + tcg_out_brcond(s, TCG_COND_LEU, args[0], args[2], const_args[2], + args[5], small); break; case TCG_COND_GT: - tcg_out_brcond(s, TCG_COND_GT, args[1], args[3], const_args[3], args[5]); - tcg_out_jxx(s, JCC_JNE, label_next); - tcg_out_brcond(s, TCG_COND_GTU, args[0], args[2], const_args[2], args[5]); + tcg_out_brcond(s, TCG_COND_GT, args[1], args[3], const_args[3], + args[5], small); + tcg_out_jxx(s, JCC_JNE, label_next, 1); + tcg_out_brcond(s, TCG_COND_GTU, args[0], args[2], const_args[2], + args[5], small); break; case TCG_COND_GE: - tcg_out_brcond(s, TCG_COND_GT, args[1], args[3], const_args[3], args[5]); - tcg_out_jxx(s, JCC_JNE, label_next); - tcg_out_brcond(s, TCG_COND_GEU, args[0], args[2], const_args[2], args[5]); + tcg_out_brcond(s, TCG_COND_GT, args[1], args[3], const_args[3], + args[5], small); + tcg_out_jxx(s, JCC_JNE, label_next, 1); + tcg_out_brcond(s, TCG_COND_GEU, args[0], args[2], const_args[2], + args[5], small); break; case TCG_COND_LTU: - tcg_out_brcond(s, TCG_COND_LTU, args[1], args[3], const_args[3], args[5]); - tcg_out_jxx(s, JCC_JNE, label_next); - tcg_out_brcond(s, TCG_COND_LTU, args[0], args[2], const_args[2], args[5]); + tcg_out_brcond(s, TCG_COND_LTU, args[1], args[3], const_args[3], + args[5], small); + tcg_out_jxx(s, JCC_JNE, label_next, 1); + tcg_out_brcond(s, TCG_COND_LTU, args[0], args[2], const_args[2], + args[5], small); break; case TCG_COND_LEU: - tcg_out_brcond(s, TCG_COND_LTU, args[1], args[3], const_args[3], args[5]); - tcg_out_jxx(s, JCC_JNE, label_next); - tcg_out_brcond(s, TCG_COND_LEU, args[0], args[2], const_args[2], args[5]); + tcg_out_brcond(s, TCG_COND_LTU, args[1], args[3], const_args[3], + args[5], small); + tcg_out_jxx(s, JCC_JNE, label_next, 1); + tcg_out_brcond(s, TCG_COND_LEU, args[0], args[2], const_args[2], + args[5], small); break; case TCG_COND_GTU: - tcg_out_brcond(s, TCG_COND_GTU, args[1], args[3], const_args[3], args[5]); - tcg_out_jxx(s, JCC_JNE, label_next); - tcg_out_brcond(s, TCG_COND_GTU, args[0], args[2], const_args[2], args[5]); + tcg_out_brcond(s, TCG_COND_GTU, args[1], args[3], const_args[3], + args[5], small); + tcg_out_jxx(s, JCC_JNE, label_next, 1); + tcg_out_brcond(s, TCG_COND_GTU, args[0], args[2], const_args[2], + args[5], small); break; case TCG_COND_GEU: - tcg_out_brcond(s, TCG_COND_GTU, args[1], args[3], const_args[3], args[5]); - tcg_out_jxx(s, JCC_JNE, label_next); - tcg_out_brcond(s, TCG_COND_GEU, args[0], args[2], const_args[2], args[5]); + tcg_out_brcond(s, TCG_COND_GTU, args[1], args[3], const_args[3], + args[5], small); + tcg_out_jxx(s, JCC_JNE, label_next, 1); + tcg_out_brcond(s, TCG_COND_GEU, args[0], args[2], const_args[2], + args[5], small); break; default: tcg_abort(); @@ -913,7 +950,7 @@ static inline void tcg_out_op(TCGContext *s, int opc, } break; case INDEX_op_br: - tcg_out_jxx(s, JCC_JMP, args[0]); + tcg_out_jxx(s, JCC_JMP, args[0], 0); break; case INDEX_op_movi_i32: tcg_out_movi(s, TCG_TYPE_I32, args[0], args[1]); @@ -1044,10 +1081,11 @@ static inline void tcg_out_op(TCGContext *s, int opc, tcg_out_modrm(s, 0x01 | (ARITH_SBB << 3), args[5], args[1]); break; case INDEX_op_brcond_i32: - tcg_out_brcond(s, args[2], args[0], args[1], const_args[1], args[3]); + tcg_out_brcond(s, args[2], args[0], args[1], const_args[1], + args[3], 0); break; case INDEX_op_brcond2_i32: - tcg_out_brcond2(s, args, const_args); + tcg_out_brcond2(s, args, const_args, 0); break; case INDEX_op_bswap16_i32: