Commit a7cdaf71 authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg/ppc: Allow the constant pool to overflow at 32k 



There is no point in coding for a 2GB offset when the max TB size
is already limited to 64k.  If we further restrict to 32k then we
can eliminate the extra ADDIS instruction.

Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
parent aeee05f5

tcg/ppc/tcg-target.inc.c

+10 −18
Original line number Diff line number Diff line
@@ -529,7 +529,6 @@ static bool patch_reloc(tcg_insn_unit *code_ptr, int type, 
                        intptr_t value, intptr_t addend)

{

    tcg_insn_unit *target;

    tcg_insn_unit old;



    value += addend;

    target = (tcg_insn_unit *)value;
@@ -540,22 +539,16 @@ static bool patch_reloc(tcg_insn_unit *code_ptr, int type, 
    case R_PPC_REL24:

        return reloc_pc24(code_ptr, target);

    case R_PPC_ADDR16:

        /* We are abusing this relocation type.  This points to a pair

           of insns, addis + load.  If the displacement is small, we

           can nop out the addis.  */

        if (value == (int16_t)value) {

            code_ptr[0] = NOP;

            old = deposit32(code_ptr[1], 0, 16, value);

            code_ptr[1] = deposit32(old, 16, 5, TCG_REG_TB);

        } else {

            int16_t lo = value;

            int hi = value - lo;

            if (hi + lo != value) {

        /*

         * We are (slightly) abusing this relocation type.  In particular,

         * assert that the low 2 bits are zero, and do not modify them.

         * That way we can use this with LD et al that have opcode bits

         * in the low 2 bits of the insn.

         */

        if ((value & 3) || value != (int16_t)value) {

            return false;

        }

            code_ptr[0] = deposit32(code_ptr[0], 0, 16, hi >> 16);

            code_ptr[1] = deposit32(code_ptr[1], 0, 16, lo);

        }

        *code_ptr = (*code_ptr & ~0xfffc) | (value & 0xfffc);

        break;

    default:

        g_assert_not_reached();
@@ -701,8 +694,7 @@ static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret, 
    if (!in_prologue && USE_REG_TB) {

        new_pool_label(s, arg, R_PPC_ADDR16, s->code_ptr,

                       -(intptr_t)s->code_gen_ptr);

        tcg_out32(s, ADDIS | TAI(ret, TCG_REG_TB, 0));

        tcg_out32(s, LD | TAI(ret, ret, 0));

        tcg_out32(s, LD | TAI(ret, TCG_REG_TB, 0));

        return;

    }