[Qemu-devel] [PATCH 3/4] tcg-ppc: Convert to helper_ret_ld/st_mmu

[Richard Henderson]

Drop the ld/st_trampolines, loading the return address into a
parameter register directly.

Signed-off-by: Richard Henderson <address@hidden>
---
 include/exec/exec-all.h |   4 +-
 tcg/ppc/tcg-target.c    | 220 +++++++++++++++++++-----------------------------
 2 files changed, 86 insertions(+), 138 deletions(-)

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index beb4149..a81e805 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -324,9 +324,7 @@ extern uintptr_t tci_tb_ptr;
    In some implementations, we pass the "logical" return address manually;
    in others, we must infer the logical return from the true return.  */
 #if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
-# if defined (_ARCH_PPC) && !defined (_ARCH_PPC64)
-#  define GETRA_LDST(RA)   (*(int32_t *)((RA) - 4))
-# elif defined(__arm__)
+# if defined(__arm__)
 /* We define two insns between the return address and the branch back to
    straight-line.  Find and decode that branch insn.  */
 #  define GETRA_LDST(RA)   tcg_getra_ldst(RA)
diff --git a/tcg/ppc/tcg-target.c b/tcg/ppc/tcg-target.c
index b0fbc54..a890319 100644
--- a/tcg/ppc/tcg-target.c
+++ b/tcg/ppc/tcg-target.c
@@ -551,27 +551,26 @@ static void add_qemu_ldst_label (TCGContext *s,
     label->label_ptr[0] = label_ptr;
 }
 
-/* helper signature: helper_ld_mmu(CPUState *env, target_ulong addr,
-   int mmu_idx) */
+/* helper signature: helper_ret_ld_mmu(CPUState *env, target_ulong addr,
+ *                                     int mmu_idx, uintptr_t ra)
+ */
 static const void * const qemu_ld_helpers[4] = {
-    helper_ldb_mmu,
-    helper_ldw_mmu,
-    helper_ldl_mmu,
-    helper_ldq_mmu,
+    helper_ret_ldub_mmu,
+    helper_ret_lduw_mmu,
+    helper_ret_ldul_mmu,
+    helper_ret_ldq_mmu,
 };
 
-/* helper signature: helper_st_mmu(CPUState *env, target_ulong addr,
-   uintxx_t val, int mmu_idx) */
+/* helper signature: helper_ret_st_mmu(CPUState *env, target_ulong addr,
+ *                                     uintxx_t val, int mmu_idx, uintptr_t ra)
+ */
 static const void * const qemu_st_helpers[4] = {
-    helper_stb_mmu,
-    helper_stw_mmu,
-    helper_stl_mmu,
-    helper_stq_mmu,
+    helper_ret_stb_mmu,
+    helper_ret_stw_mmu,
+    helper_ret_stl_mmu,
+    helper_ret_stq_mmu,
 };
 
-static void *ld_trampolines[4];
-static void *st_trampolines[4];
-
 static void tcg_out_tlb_check (TCGContext *s, int r0, int r1, int r2,
                                int addr_reg, int addr_reg2, int s_bits,
                                int offset1, int offset2, uint8_t **label_ptr)
@@ -608,9 +607,14 @@ static void tcg_out_tlb_check (TCGContext *s, int r0, int 
r1, int r2,
     tcg_out32 (s, CMP | BF (6) | RA (addr_reg2) | RB (r1));
     tcg_out32 (s, CRAND | BT (7, CR_EQ) | BA (6, CR_EQ) | BB (7, CR_EQ));
 #endif
+
+    /* Use a conditional branch-and-link so that we load a pointer to
+       somewhere within the current opcode, for passing on to the helper.
+       This address cannot be used for a tail call, but it's shorter
+       than forming an address from scratch.  */
     *label_ptr = s->code_ptr;
     retranst = ((uint16_t *) s->code_ptr)[1] & ~3;
-    tcg_out32 (s, BC | BI (7, CR_EQ) | retranst | BO_COND_FALSE);
+    tcg_out32(s, BC | BI(7, CR_EQ) | retranst | BO_COND_FALSE | LK);
 
     /* r0 now contains &env->tlb_table[mem_index][index].addr_x */
     tcg_out32 (s, (LWZ
@@ -833,132 +837,99 @@ static void tcg_out_qemu_st (TCGContext *s, const TCGArg 
*args, int opc)
 }
 
 #if defined(CONFIG_SOFTMMU)
-static void tcg_out_qemu_ld_slow_path (TCGContext *s, TCGLabelQemuLdst *label)
+static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
 {
-    int s_bits;
-    int ir;
-    int opc = label->opc;
-    int mem_index = label->mem_index;
-    int data_reg = label->datalo_reg;
-    int data_reg2 = label->datahi_reg;
-    int addr_reg = label->addrlo_reg;
-    uint8_t *raddr = label->raddr;
-    uint8_t **label_ptr = &label->label_ptr[0];
+    TCGReg ir, datalo, datahi;
+    int opc = lb->opc;
 
-    s_bits = opc & 3;
+    reloc_pc14(lb->label_ptr[0], (uintptr_t)s->code_ptr);
 
-    /* resolve label address */
-    reloc_pc14 (label_ptr[0], (tcg_target_long) s->code_ptr);
+    ir = TCG_REG_R3;
+    tcg_out_mov(s, TCG_TYPE_PTR, ir++, TCG_AREG0);
 
-    /* slow path */
-    ir = 4;
-#if TARGET_LONG_BITS == 32
-    tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
-#else
+    if (TARGET_LONG_BITS == 32) {
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->addrlo_reg);
+    } else {
 #ifdef TCG_TARGET_CALL_ALIGN_ARGS
-    ir |= 1;
-#endif
-    tcg_out_mov (s, TCG_TYPE_I32, ir++, label->addrhi_reg);
-    tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
+        ir |= 1;
 #endif
-    tcg_out_movi (s, TCG_TYPE_I32, ir, mem_index);
-    tcg_out_call (s, (tcg_target_long) ld_trampolines[s_bits], 1);
-    tcg_out32 (s, (tcg_target_long) raddr);
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->addrhi_reg);
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->addrlo_reg);
+    }
+
+    tcg_out_movi(s, TCG_TYPE_I32, ir++, lb->mem_index);
+    tcg_out32(s, MFSPR | RT(ir++) | LR);
+
+    tcg_out_call(s, (uintptr_t)qemu_ld_helpers[opc & 3], 1);
+
+    datalo = lb->datalo_reg;
     switch (opc) {
     case 0|4:
-        tcg_out32 (s, EXTSB | RA (data_reg) | RS (3));
+        tcg_out32(s, EXTSB | RA(datalo) | RS(TCG_REG_R3));
         break;
     case 1|4:
-        tcg_out32 (s, EXTSH | RA (data_reg) | RS (3));
+        tcg_out32(s, EXTSH | RA(datalo) | RS(TCG_REG_R3));
         break;
-    case 0:
-    case 1:
-    case 2:
-        if (data_reg != 3)
-            tcg_out_mov (s, TCG_TYPE_I32, data_reg, 3);
+
+    default:
+        tcg_out_mov(s, TCG_TYPE_I32, datalo, TCG_REG_R3);
         break;
+
     case 3:
-        if (data_reg == 3) {
-            if (data_reg2 == 4) {
-                tcg_out_mov (s, TCG_TYPE_I32, 0, 4);
-                tcg_out_mov (s, TCG_TYPE_I32, 4, 3);
-                tcg_out_mov (s, TCG_TYPE_I32, 3, 0);
-            }
-            else {
-                tcg_out_mov (s, TCG_TYPE_I32, data_reg2, 3);
-                tcg_out_mov (s, TCG_TYPE_I32, 3, 4);
-            }
-        }
-        else {
-            if (data_reg != 4) tcg_out_mov (s, TCG_TYPE_I32, data_reg, 4);
-            if (data_reg2 != 3) tcg_out_mov (s, TCG_TYPE_I32, data_reg2, 3);
+        datahi = lb->datahi_reg;
+        if (datalo != TCG_REG_R3) {
+            tcg_out_mov(s, TCG_TYPE_I32, datalo, TCG_REG_R4);
+            tcg_out_mov(s, TCG_TYPE_I32, datahi, TCG_REG_R3);
+        } else if (datahi != TCG_REG_R4) {
+            tcg_out_mov(s, TCG_TYPE_I32, datahi, TCG_REG_R3);
+            tcg_out_mov(s, TCG_TYPE_I32, datalo, TCG_REG_R4);
+        } else {
+            tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_R0, TCG_REG_R4);
+            tcg_out_mov(s, TCG_TYPE_I32, datahi, TCG_REG_R3);
+            tcg_out_mov(s, TCG_TYPE_I32, datalo, TCG_REG_R0);
         }
         break;
     }
+
     /* Jump to the code corresponding to next IR of qemu_st */
-    tcg_out_b (s, 0, (tcg_target_long) raddr);
+    tcg_out_b(s, 0, (uintptr_t)lb->raddr);
 }
 
-static void tcg_out_qemu_st_slow_path (TCGContext *s, TCGLabelQemuLdst *label)
+static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
 {
-    int ir;
-    int opc = label->opc;
-    int mem_index = label->mem_index;
-    int data_reg = label->datalo_reg;
-    int data_reg2 = label->datahi_reg;
-    int addr_reg = label->addrlo_reg;
-    uint8_t *raddr = label->raddr;
-    uint8_t **label_ptr = &label->label_ptr[0];
-
-    /* resolve label address */
-    reloc_pc14 (label_ptr[0], (tcg_target_long) s->code_ptr);
-
-    /* slow path */
-    ir = 4;
-#if TARGET_LONG_BITS == 32
-    tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
-#else
+    TCGReg ir;
+
+    reloc_pc14(lb->label_ptr[0], (uintptr_t)s->code_ptr);
+
+    ir = TCG_REG_R3;
+    tcg_out_mov(s, TCG_TYPE_PTR, ir++, TCG_AREG0);
+
+    if (TARGET_LONG_BITS == 32) {
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->addrlo_reg);
+    } else {
 #ifdef TCG_TARGET_CALL_ALIGN_ARGS
-    ir |= 1;
-#endif
-    tcg_out_mov (s, TCG_TYPE_I32, ir++, label->addrhi_reg);
-    tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
+        ir |= 1;
 #endif
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->addrhi_reg);
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->addrlo_reg);
+    }
 
-    switch (opc) {
-    case 0:
-        tcg_out32 (s, (RLWINM
-                       | RA (ir)
-                       | RS (data_reg)
-                       | SH (0)
-                       | MB (24)
-                       | ME (31)));
-        break;
-    case 1:
-        tcg_out32 (s, (RLWINM
-                       | RA (ir)
-                       | RS (data_reg)
-                       | SH (0)
-                       | MB (16)
-                       | ME (31)));
-        break;
-    case 2:
-        tcg_out_mov (s, TCG_TYPE_I32, ir, data_reg);
-        break;
-    case 3:
+    if (lb->opc != 3) {
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->datalo_reg);
+    } else {
 #ifdef TCG_TARGET_CALL_ALIGN_ARGS
         ir |= 1;
 #endif
-        tcg_out_mov (s, TCG_TYPE_I32, ir++, data_reg2);
-        tcg_out_mov (s, TCG_TYPE_I32, ir, data_reg);
-        break;
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->datahi_reg);
+        tcg_out_mov(s, TCG_TYPE_I32, ir++, lb->datalo_reg);
     }
-    ir++;
 
-    tcg_out_movi (s, TCG_TYPE_I32, ir, mem_index);
-    tcg_out_call (s, (tcg_target_long) st_trampolines[opc], 1);
-    tcg_out32 (s, (tcg_target_long) raddr);
-    tcg_out_b (s, 0, (tcg_target_long) raddr);
+    tcg_out_movi(s, TCG_TYPE_I32, ir++, lb->mem_index);
+    tcg_out32(s, MFSPR | RT(ir++) | LR);
+
+    tcg_out_call(s, (uintptr_t)qemu_st_helpers[lb->opc], 1);
+
+    tcg_out_b(s, 0, (uintptr_t)lb->raddr);
 }
 
 void tcg_out_tb_finalize(TCGContext *s)
@@ -979,17 +950,6 @@ void tcg_out_tb_finalize(TCGContext *s)
 }
 #endif
 
-#ifdef CONFIG_SOFTMMU
-static void emit_ldst_trampoline (TCGContext *s, const void *ptr)
-{
-    tcg_out32 (s, MFSPR | RT (3) | LR);
-    tcg_out32 (s, ADDI | RT (3) | RA (3) | 4);
-    tcg_out32 (s, MTSPR | RS (3) | LR);
-    tcg_out_mov (s, TCG_TYPE_I32, 3, TCG_AREG0);
-    tcg_out_b (s, 0, (tcg_target_long) ptr);
-}
-#endif
-
 static void tcg_target_qemu_prologue (TCGContext *s)
 {
     int i, frame_size;
@@ -1050,16 +1010,6 @@ static void tcg_target_qemu_prologue (TCGContext *s)
     tcg_out32 (s, MTSPR | RS (0) | LR);
     tcg_out32 (s, ADDI | RT (1) | RA (1) | frame_size);
     tcg_out32 (s, BCLR | BO_ALWAYS);
-
-#ifdef CONFIG_SOFTMMU
-    for (i = 0; i < 4; ++i) {
-        ld_trampolines[i] = s->code_ptr;
-        emit_ldst_trampoline (s, qemu_ld_helpers[i]);
-
-        st_trampolines[i] = s->code_ptr;
-        emit_ldst_trampoline (s, qemu_st_helpers[i]);
-    }
-#endif
 }
 
 static void tcg_out_ld (TCGContext *s, TCGType type, TCGReg ret, TCGReg arg1,
-- 
1.8.3.1