tcg-arm: Convert to CONFIG_QEMU_LDST_OPTIMIZATION

Move the slow path out of line, as the TODO's mention.
This allows the fast path to be unconditional, which can
speed up the fast path as well, depending on the core.

Signed-off-by: Richard Henderson <rth@twiddle.net>

1 files changed, 202 insertions, 107 deletions

diff --git a/tcg/arm/tcg-target.c b/tcg/arm/tcg-target.c
index eb697f2942..d6afa2f309 100644
--- a/tcg/arm/tcg-target.c
+++ b/tcg/arm/tcg-target.c
@@ -419,6 +419,20 @@ static inline void tcg_out_dat_reg(TCGContext *s,
                     (rn << 16) | (rd << 12) | shift | rm);
 }
 
+static inline void tcg_out_nop(TCGContext *s)
+{
+    if (use_armv7_instructions) {
+        /* Architected nop introduced in v6k.  */
+        /* ??? This is an MSR (imm) 0,0,0 insn.  Anyone know if this
+           also Just So Happened to do nothing on pre-v6k so that we
+           don't need to conditionalize it?  */
+        tcg_out32(s, 0xe320f000);
+    } else {
+        /* Prior to that the assembler uses mov r0, r0.  */
+        tcg_out_dat_reg(s, COND_AL, ARITH_MOV, 0, 0, 0, SHIFT_IMM_LSL(0));
+    }
+}
+
 static inline void tcg_out_mov_reg(TCGContext *s, int cond, int rd, int rm)
 {
     /* Simple reg-reg move, optimising out the 'do nothing' case */
@@ -1200,6 +1214,134 @@ static void tcg_out_tlb_read(TCGContext *s, TCGReg addrlo, TCGReg addrhi,
                         TCG_REG_R1, addrhi, SHIFT_IMM_LSL(0));
     }
 }
+
+/* Record the context of a call to the out of line helper code for the slow
+   path for a load or store, so that we can later generate the correct
+   helper code.  */
+static void add_qemu_ldst_label(TCGContext *s, int is_ld, int opc,
+                                int data_reg, int data_reg2, int addrlo_reg,
+                                int addrhi_reg, int mem_index,
+                                uint8_t *raddr, uint8_t *label_ptr)
+{
+    int idx;
+    TCGLabelQemuLdst *label;
+
+    if (s->nb_qemu_ldst_labels >= TCG_MAX_QEMU_LDST) {
+        tcg_abort();
+    }
+
+    idx = s->nb_qemu_ldst_labels++;
+    label = (TCGLabelQemuLdst *)&s->qemu_ldst_labels[idx];
+    label->is_ld = is_ld;
+    label->opc = opc;
+    label->datalo_reg = data_reg;
+    label->datahi_reg = data_reg2;
+    label->addrlo_reg = addrlo_reg;
+    label->addrhi_reg = addrhi_reg;
+    label->mem_index = mem_index;
+    label->raddr = raddr;
+    label->label_ptr[0] = label_ptr;
+}
+
+static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
+{
+    TCGReg argreg, data_reg, data_reg2;
+    uint8_t *start;
+
+    reloc_pc24(lb->label_ptr[0], (tcg_target_long)s->code_ptr);
+
+    argreg = tcg_out_arg_reg32(s, TCG_REG_R0, TCG_AREG0);
+    if (TARGET_LONG_BITS == 64) {
+        argreg = tcg_out_arg_reg64(s, argreg, lb->addrlo_reg, lb->addrhi_reg);
+    } else {
+        argreg = tcg_out_arg_reg32(s, argreg, lb->addrlo_reg);
+    }
+    argreg = tcg_out_arg_imm32(s, argreg, lb->mem_index);
+    tcg_out_call(s, (tcg_target_long) qemu_ld_helpers[lb->opc & 3]);
+
+    data_reg = lb->datalo_reg;
+    data_reg2 = lb->datahi_reg;
+
+    start = s->code_ptr;
+    switch (lb->opc) {
+    case 0 | 4:
+        tcg_out_ext8s(s, COND_AL, data_reg, TCG_REG_R0);
+        break;
+    case 1 | 4:
+        tcg_out_ext16s(s, COND_AL, data_reg, TCG_REG_R0);
+        break;
+    case 0:
+    case 1:
+    case 2:
+    default:
+        tcg_out_mov_reg(s, COND_AL, data_reg, TCG_REG_R0);
+        break;
+    case 3:
+        tcg_out_mov_reg(s, COND_AL, data_reg, TCG_REG_R0);
+        tcg_out_mov_reg(s, COND_AL, data_reg2, TCG_REG_R1);
+        break;
+    }
+
+    /* For GETPC_LDST in exec-all.h, we architect exactly 2 insns between
+       the call and the branch back to straight-line code.  Note that the
+       moves above could be elided by register allocation, nor do we know
+       which code alternative we chose for extension.  */
+    switch (s->code_ptr - start) {
+    case 0:
+        tcg_out_nop(s);
+        /* FALLTHRU */
+    case 4:
+        tcg_out_nop(s);
+        /* FALLTHRU */
+    case 8:
+        break;
+    default:
+        abort();
+    }
+
+    tcg_out_goto(s, COND_AL, (tcg_target_long)lb->raddr);
+}
+
+static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
+{
+    TCGReg argreg, data_reg, data_reg2;
+
+    reloc_pc24(lb->label_ptr[0], (tcg_target_long)s->code_ptr);
+
+    argreg = TCG_REG_R0;
+    argreg = tcg_out_arg_reg32(s, argreg, TCG_AREG0);
+    if (TARGET_LONG_BITS == 64) {
+        argreg = tcg_out_arg_reg64(s, argreg, lb->addrlo_reg, lb->addrhi_reg);
+    } else {
+        argreg = tcg_out_arg_reg32(s, argreg, lb->addrlo_reg);
+    }
+
+    data_reg = lb->datalo_reg;
+    data_reg2 = lb->datahi_reg;
+    switch (lb->opc) {
+    case 0:
+        argreg = tcg_out_arg_reg8(s, argreg, data_reg);
+        break;
+    case 1:
+        argreg = tcg_out_arg_reg16(s, argreg, data_reg);
+        break;
+    case 2:
+        argreg = tcg_out_arg_reg32(s, argreg, data_reg);
+        break;
+    case 3:
+        argreg = tcg_out_arg_reg64(s, argreg, data_reg, data_reg2);
+        break;
+    }
+
+    argreg = tcg_out_arg_imm32(s, argreg, lb->mem_index);
+    tcg_out_call(s, (tcg_target_long) qemu_st_helpers[lb->opc & 3]);
+
+    /* For GETPC_LDST in exec-all.h, we architect exactly 2 insns between
+       the call and the branch back to straight-line code.  */
+    tcg_out_nop(s);
+    tcg_out_nop(s);
+    tcg_out_goto(s, COND_AL, (tcg_target_long)lb->raddr);
+}
 #endif /* SOFTMMU */
 
 static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, int opc)
@@ -1208,8 +1350,8 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, int opc)
     bool bswap;
 #ifdef CONFIG_SOFTMMU
     int mem_index, s_bits;
-    TCGReg argreg, addr_reg2;
-    uint32_t *label_ptr;
+    TCGReg addr_reg2;
+    uint8_t *label_ptr;
 #endif
 #ifdef TARGET_WORDS_BIGENDIAN
     bswap = 1;
@@ -1228,89 +1370,56 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, int opc)
     tcg_out_tlb_read(s, addr_reg, addr_reg2, s_bits,
                      offsetof(CPUArchState, tlb_table[mem_index][0].addr_read));
 
-    tcg_out_ld32_12(s, COND_EQ, TCG_REG_R1, TCG_REG_R2,
+    label_ptr = s->code_ptr;
+    tcg_out_b_noaddr(s, COND_NE);
+
+    tcg_out_ld32_12(s, COND_AL, TCG_REG_R1, TCG_REG_R2,
                     offsetof(CPUTLBEntry, addend)
                     - offsetof(CPUTLBEntry, addr_read));
 
     switch (opc) {
     case 0:
-        tcg_out_ld8_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
+        tcg_out_ld8_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
         break;
     case 0 | 4:
-        tcg_out_ld8s_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
+        tcg_out_ld8s_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
         break;
     case 1:
-        tcg_out_ld16u_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
+        tcg_out_ld16u_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
         if (bswap) {
-            tcg_out_bswap16(s, COND_EQ, data_reg, data_reg);
+            tcg_out_bswap16(s, COND_AL, data_reg, data_reg);
         }
         break;
     case 1 | 4:
         if (bswap) {
-            tcg_out_ld16u_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
-            tcg_out_bswap16s(s, COND_EQ, data_reg, data_reg);
+            tcg_out_ld16u_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
+            tcg_out_bswap16s(s, COND_AL, data_reg, data_reg);
         } else {
-            tcg_out_ld16s_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
+            tcg_out_ld16s_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
         }
         break;
     case 2:
     default:
-        tcg_out_ld32_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
+        tcg_out_ld32_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
         if (bswap) {
-            tcg_out_bswap32(s, COND_EQ, data_reg, data_reg);
+            tcg_out_bswap32(s, COND_AL, data_reg, data_reg);
         }
         break;
     case 3:
         if (bswap) {
-            tcg_out_ld32_rwb(s, COND_EQ, data_reg2, TCG_REG_R1, addr_reg);
-            tcg_out_ld32_12(s, COND_EQ, data_reg, TCG_REG_R1, 4);
-            tcg_out_bswap32(s, COND_EQ, data_reg2, data_reg2);
-            tcg_out_bswap32(s, COND_EQ, data_reg, data_reg);
+            tcg_out_ld32_rwb(s, COND_AL, data_reg2, TCG_REG_R1, addr_reg);
+            tcg_out_ld32_12(s, COND_AL, data_reg, TCG_REG_R1, 4);
+            tcg_out_bswap32(s, COND_AL, data_reg2, data_reg2);
+            tcg_out_bswap32(s, COND_AL, data_reg, data_reg);
         } else {
-            tcg_out_ld32_rwb(s, COND_EQ, data_reg, TCG_REG_R1, addr_reg);
-            tcg_out_ld32_12(s, COND_EQ, data_reg2, TCG_REG_R1, 4);
+            tcg_out_ld32_rwb(s, COND_AL, data_reg, TCG_REG_R1, addr_reg);
+            tcg_out_ld32_12(s, COND_AL, data_reg2, TCG_REG_R1, 4);
         }
         break;
     }
 
-    label_ptr = (void *) s->code_ptr;
-    tcg_out_b_noaddr(s, COND_EQ);
-
-    /* TODO: move this code to where the constants pool will be */
-    /* Note that this code relies on the constraints we set in arm_op_defs[]
-     * to ensure that later arguments are not passed to us in registers we
-     * trash by moving the earlier arguments into them.
-     */
-    argreg = TCG_REG_R0;
-    argreg = tcg_out_arg_reg32(s, argreg, TCG_AREG0);
-    if (TARGET_LONG_BITS == 64) {
-        argreg = tcg_out_arg_reg64(s, argreg, addr_reg, addr_reg2);
-    } else {
-        argreg = tcg_out_arg_reg32(s, argreg, addr_reg);
-    }
-    argreg = tcg_out_arg_imm32(s, argreg, mem_index);
-    tcg_out_call(s, (tcg_target_long) qemu_ld_helpers[s_bits]);
-
-    switch (opc) {
-    case 0 | 4:
-        tcg_out_ext8s(s, COND_AL, data_reg, TCG_REG_R0);
-        break;
-    case 1 | 4:
-        tcg_out_ext16s(s, COND_AL, data_reg, TCG_REG_R0);
-        break;
-    case 0:
-    case 1:
-    case 2:
-    default:
-        tcg_out_mov_reg(s, COND_AL, data_reg, TCG_REG_R0);
-        break;
-    case 3:
-        tcg_out_mov_reg(s, COND_AL, data_reg, TCG_REG_R0);
-        tcg_out_mov_reg(s, COND_AL, data_reg2, TCG_REG_R1);
-        break;
-    }
-
-    reloc_pc24(label_ptr, (tcg_target_long)s->code_ptr);
+    add_qemu_ldst_label(s, 1, opc, data_reg, data_reg2, addr_reg, addr_reg2,
+                        mem_index, s->code_ptr, label_ptr);
 #else /* !CONFIG_SOFTMMU */
     if (GUEST_BASE) {
         uint32_t offset = GUEST_BASE;
@@ -1379,8 +1488,8 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, int opc)
     bool bswap;
 #ifdef CONFIG_SOFTMMU
     int mem_index, s_bits;
-    TCGReg argreg, addr_reg2;
-    uint32_t *label_ptr;
+    TCGReg addr_reg2;
+    uint8_t *label_ptr;
 #endif
 #ifdef TARGET_WORDS_BIGENDIAN
     bswap = 1;
@@ -1400,79 +1509,49 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, int opc)
                      offsetof(CPUArchState,
                               tlb_table[mem_index][0].addr_write));
 
-    tcg_out_ld32_12(s, COND_EQ, TCG_REG_R1, TCG_REG_R2,
+    label_ptr = s->code_ptr;
+    tcg_out_b_noaddr(s, COND_NE);
+
+    tcg_out_ld32_12(s, COND_AL, TCG_REG_R1, TCG_REG_R2,
                     offsetof(CPUTLBEntry, addend)
                     - offsetof(CPUTLBEntry, addr_write));
 
     switch (opc) {
     case 0:
-        tcg_out_st8_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
+        tcg_out_st8_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
         break;
     case 1:
         if (bswap) {
-            tcg_out_bswap16st(s, COND_EQ, TCG_REG_R0, data_reg);
-            tcg_out_st16_r(s, COND_EQ, TCG_REG_R0, addr_reg, TCG_REG_R1);
+            tcg_out_bswap16st(s, COND_AL, TCG_REG_R0, data_reg);
+            tcg_out_st16_r(s, COND_AL, TCG_REG_R0, addr_reg, TCG_REG_R1);
         } else {
-            tcg_out_st16_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
+            tcg_out_st16_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
         }
         break;
     case 2:
     default:
         if (bswap) {
-            tcg_out_bswap32(s, COND_EQ, TCG_REG_R0, data_reg);
-            tcg_out_st32_r(s, COND_EQ, TCG_REG_R0, addr_reg, TCG_REG_R1);
+            tcg_out_bswap32(s, COND_AL, TCG_REG_R0, data_reg);
+            tcg_out_st32_r(s, COND_AL, TCG_REG_R0, addr_reg, TCG_REG_R1);
         } else {
-            tcg_out_st32_r(s, COND_EQ, data_reg, addr_reg, TCG_REG_R1);
+            tcg_out_st32_r(s, COND_AL, data_reg, addr_reg, TCG_REG_R1);
         }
         break;
     case 3:
         if (bswap) {
-            tcg_out_bswap32(s, COND_EQ, TCG_REG_R0, data_reg2);
-            tcg_out_st32_rwb(s, COND_EQ, TCG_REG_R0, TCG_REG_R1, addr_reg);
-            tcg_out_bswap32(s, COND_EQ, TCG_REG_R0, data_reg);
-            tcg_out_st32_12(s, COND_EQ, TCG_REG_R0, TCG_REG_R1, 4);
+            tcg_out_bswap32(s, COND_AL, TCG_REG_R0, data_reg2);
+            tcg_out_st32_rwb(s, COND_AL, TCG_REG_R0, TCG_REG_R1, addr_reg);
+            tcg_out_bswap32(s, COND_AL, TCG_REG_R0, data_reg);
+            tcg_out_st32_12(s, COND_AL, TCG_REG_R0, TCG_REG_R1, 4);
         } else {
-            tcg_out_st32_rwb(s, COND_EQ, data_reg, TCG_REG_R1, addr_reg);
-            tcg_out_st32_12(s, COND_EQ, data_reg2, TCG_REG_R1, 4);
+            tcg_out_st32_rwb(s, COND_AL, data_reg, TCG_REG_R1, addr_reg);
+            tcg_out_st32_12(s, COND_AL, data_reg2, TCG_REG_R1, 4);
         }
         break;
     }
 
-    label_ptr = (void *) s->code_ptr;
-    tcg_out_b_noaddr(s, COND_EQ);
-
-    /* TODO: move this code to where the constants pool will be */
-    /* Note that this code relies on the constraints we set in arm_op_defs[]
-     * to ensure that later arguments are not passed to us in registers we
-     * trash by moving the earlier arguments into them.
-     */
-    argreg = TCG_REG_R0;
-    argreg = tcg_out_arg_reg32(s, argreg, TCG_AREG0);
-    if (TARGET_LONG_BITS == 64) {
-        argreg = tcg_out_arg_reg64(s, argreg, addr_reg, addr_reg2);
-    } else {
-        argreg = tcg_out_arg_reg32(s, argreg, addr_reg);
-    }
-
-    switch (opc) {
-    case 0:
-        argreg = tcg_out_arg_reg8(s, argreg, data_reg);
-        break;
-    case 1:
-        argreg = tcg_out_arg_reg16(s, argreg, data_reg);
-        break;
-    case 2:
-        argreg = tcg_out_arg_reg32(s, argreg, data_reg);
-        break;
-    case 3:
-        argreg = tcg_out_arg_reg64(s, argreg, data_reg, data_reg2);
-        break;
-    }
-
-    argreg = tcg_out_arg_imm32(s, argreg, mem_index);
-    tcg_out_call(s, (tcg_target_long) qemu_st_helpers[s_bits]);
-
-    reloc_pc24(label_ptr, (tcg_target_long)s->code_ptr);
+    add_qemu_ldst_label(s, 0, opc, data_reg, data_reg2, addr_reg, addr_reg2,
+                        mem_index, s->code_ptr, label_ptr);
 #else /* !CONFIG_SOFTMMU */
     if (GUEST_BASE) {
         uint32_t offset = GUEST_BASE;
@@ -1872,6 +1951,22 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
     }
 }
 
+#ifdef CONFIG_SOFTMMU
+/* Generate TB finalization at the end of block.  */
+void tcg_out_tb_finalize(TCGContext *s)
+{
+    int i;
+    for (i = 0; i < s->nb_qemu_ldst_labels; i++) {
+        TCGLabelQemuLdst *label = &s->qemu_ldst_labels[i];
+        if (label->is_ld) {
+            tcg_out_qemu_ld_slow_path(s, label);
+        } else {
+            tcg_out_qemu_st_slow_path(s, label);
+        }
+    }
+}
+#endif /* SOFTMMU */
+
 static const TCGTargetOpDef arm_op_defs[] = {
     { INDEX_op_exit_tb, { } },
     { INDEX_op_goto_tb, { } },