i386: Remove REGPARM

Use stack based calling convention (GCC default) for interfacing with
generated code instead of register based convention (regparm(3)).

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

4 files changed, 58 insertions, 77 deletions

diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
index fafd900c5a..c4e940da5b 100644
--- a/tcg/i386/tcg-target.c
+++ b/tcg/i386/tcg-target.c
@@ -116,17 +116,7 @@ static inline int tcg_target_get_call_iarg_regs_count(int flags)
         return 6;
     }
 
-    flags &= TCG_CALL_TYPE_MASK;
-    switch(flags) {
-    case TCG_CALL_TYPE_STD:
-        return 0;
-    case TCG_CALL_TYPE_REGPARM_1:
-    case TCG_CALL_TYPE_REGPARM_2:
-    case TCG_CALL_TYPE_REGPARM:
-        return flags - TCG_CALL_TYPE_REGPARM_1 + 1;
-    default:
-        tcg_abort();
-    }
+    return 0;
 }
 
 /* parse target specific constraints */
@@ -1148,7 +1138,12 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
     int data_reg, data_reg2 = 0;
     int addrlo_idx;
 #if defined(CONFIG_SOFTMMU)
-    int mem_index, s_bits, arg_idx;
+    int mem_index, s_bits;
+#if TCG_TARGET_REG_BITS == 64
+    int arg_idx;
+#else
+    int stack_adjust;
+#endif
     uint8_t *label_ptr[3];
 #endif
 
@@ -1184,16 +1179,33 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args,
     }
 
     /* XXX: move that code at the end of the TB */
+#if TCG_TARGET_REG_BITS == 32
+    tcg_out_pushi(s, mem_index);
+    stack_adjust = 4;
+    if (TARGET_LONG_BITS == 64) {
+        tcg_out_push(s, args[addrlo_idx + 1]);
+        stack_adjust += 4;
+    }
+    tcg_out_push(s, args[addrlo_idx]);
+    stack_adjust += 4;
+#else
     /* The first argument is already loaded with addrlo.  */
     arg_idx = 1;
-    if (TCG_TARGET_REG_BITS == 32 && TARGET_LONG_BITS == 64) {
-        tcg_out_mov(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[arg_idx++],
-                    args[addrlo_idx + 1]);
-    }
     tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[arg_idx],
                  mem_index);
+#endif
+
     tcg_out_calli(s, (tcg_target_long)qemu_ld_helpers[s_bits]);
 
+#if TCG_TARGET_REG_BITS == 32
+    if (stack_adjust == (TCG_TARGET_REG_BITS / 8)) {
+        /* Pop and discard.  This is 2 bytes smaller than the add.  */
+        tcg_out_pop(s, TCG_REG_ECX);
+    } else if (stack_adjust != 0) {
+        tcg_out_addi(s, TCG_REG_CALL_STACK, stack_adjust);
+    }
+#endif
+
     switch(opc) {
     case 0 | 4:
         tcg_out_ext8s(s, data_reg, TCG_REG_EAX, P_REXW);
@@ -1359,45 +1371,27 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args,
     }
 
     /* XXX: move that code at the end of the TB */
-    if (TCG_TARGET_REG_BITS == 64) {
-        tcg_out_mov(s, (opc == 3 ? TCG_TYPE_I64 : TCG_TYPE_I32),
-                    TCG_REG_RSI, data_reg);
-        tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_RDX, mem_index);
-        stack_adjust = 0;
-    } else if (TARGET_LONG_BITS == 32) {
-        tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_EDX, data_reg);
-        if (opc == 3) {
-            tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_ECX, data_reg2);
-            tcg_out_pushi(s, mem_index);
-            stack_adjust = 4;
-        } else {
-            tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_ECX, mem_index);
-            stack_adjust = 0;
-        }
-    } else {
-        if (opc == 3) {
-            tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_EDX, args[addrlo_idx + 1]);
-            tcg_out_pushi(s, mem_index);
-            tcg_out_push(s, data_reg2);
-            tcg_out_push(s, data_reg);
-            stack_adjust = 12;
-        } else {
-            tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_EDX, args[addrlo_idx + 1]);
-            switch(opc) {
-            case 0:
-                tcg_out_ext8u(s, TCG_REG_ECX, data_reg);
-                break;
-            case 1:
-                tcg_out_ext16u(s, TCG_REG_ECX, data_reg);
-                break;
-            case 2:
-                tcg_out_mov(s, TCG_TYPE_I32, TCG_REG_ECX, data_reg);
-                break;
-            }
-            tcg_out_pushi(s, mem_index);
-            stack_adjust = 4;
-        }
+#if TCG_TARGET_REG_BITS == 32
+    tcg_out_pushi(s, mem_index);
+    stack_adjust = 4;
+    if (opc == 3) {
+        tcg_out_push(s, data_reg2);
+        stack_adjust += 4;
+    }
+    tcg_out_push(s, data_reg);
+    stack_adjust += 4;
+    if (TARGET_LONG_BITS == 64) {
+        tcg_out_push(s, args[addrlo_idx + 1]);
+        stack_adjust += 4;
     }
+    tcg_out_push(s, args[addrlo_idx]);
+    stack_adjust += 4;
+#else
+    tcg_out_mov(s, (opc == 3 ? TCG_TYPE_I64 : TCG_TYPE_I32),
+                TCG_REG_RSI, data_reg);
+    tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_RDX, mem_index);
+    stack_adjust = 0;
+#endif
 
     tcg_out_calli(s, (tcg_target_long)qemu_st_helpers[s_bits]);
 
@@ -1962,9 +1956,15 @@ static void tcg_target_qemu_prologue(TCGContext *s)
         tcg_out_push(s, tcg_target_callee_save_regs[i]);
     }
 
-    tcg_out_addi(s, TCG_REG_ESP, -stack_addend);
-
+#if TCG_TARGET_REG_BITS == 32
+    tcg_out_ld(s, TCG_TYPE_PTR, TCG_AREG0, TCG_REG_ESP,
+               (ARRAY_SIZE(tcg_target_callee_save_regs) + 1) * 4);
+    tcg_out_ld(s, TCG_TYPE_PTR, tcg_target_call_iarg_regs[1], TCG_REG_ESP,
+               (ARRAY_SIZE(tcg_target_callee_save_regs) + 2) * 4);
+#else
     tcg_out_mov(s, TCG_TYPE_PTR, TCG_AREG0, tcg_target_call_iarg_regs[0]);
+#endif
+    tcg_out_addi(s, TCG_REG_ESP, -stack_addend);
 
     /* jmp *tb.  */
     tcg_out_modrm(s, OPC_GRP5, EXT5_JMPN_Ev, tcg_target_call_iarg_regs[1]);
diff --git a/tcg/ppc/tcg-target.h b/tcg/ppc/tcg-target.h
index 3f22aaac9d..2f37fd289b 100644
--- a/tcg/ppc/tcg-target.h
+++ b/tcg/ppc/tcg-target.h
@@ -98,5 +98,5 @@ typedef enum {
 #define TCG_TARGET_HAS_GUEST_BASE
 
 #define tcg_qemu_tb_exec(env, tb_ptr) \
-    ((long REGPARM __attribute__ ((longcall)) \
+    ((long __attribute__ ((longcall)) \
       (*)(void *, void *))code_gen_prologue)(env, tb_ptr)
diff --git a/tcg/tcg.c b/tcg/tcg.c
index ad2e983c2b..ccfcd1abe1 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -594,9 +594,6 @@ void tcg_register_helper(void *func, const char *name)
 void tcg_gen_callN(TCGContext *s, TCGv_ptr func, unsigned int flags,
                    int sizemask, TCGArg ret, int nargs, TCGArg *args)
 {
-#if defined(TCG_TARGET_I386) && TCG_TARGET_REG_BITS < 64
-    int call_type;
-#endif
     int i;
     int real_args;
     int nb_rets;
@@ -621,9 +618,6 @@ void tcg_gen_callN(TCGContext *s, TCGv_ptr func, unsigned int flags,
 
     *gen_opc_ptr++ = INDEX_op_call;
     nparam = gen_opparam_ptr++;
-#if defined(TCG_TARGET_I386) && TCG_TARGET_REG_BITS < 64
-    call_type = (flags & TCG_CALL_TYPE_MASK);
-#endif
     if (ret != TCG_CALL_DUMMY_ARG) {
 #if TCG_TARGET_REG_BITS < 64
         if (sizemask & 1) {
@@ -649,14 +643,6 @@ void tcg_gen_callN(TCGContext *s, TCGv_ptr func, unsigned int flags,
 #if TCG_TARGET_REG_BITS < 64
         int is_64bit = sizemask & (1 << (i+1)*2);
         if (is_64bit) {
-#ifdef TCG_TARGET_I386
-            /* REGPARM case: if the third parameter is 64 bit, it is
-               allocated on the stack */
-            if (i == 2 && call_type == TCG_CALL_TYPE_REGPARM) {
-                call_type = TCG_CALL_TYPE_REGPARM_2;
-                flags = (flags & ~TCG_CALL_TYPE_MASK) | call_type;
-            }
-#endif
 #ifdef TCG_TARGET_CALL_ALIGN_ARGS
             /* some targets want aligned 64 bit args */
             if (real_args & 1) {
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 9bc9fc9052..5f6c647ea5 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -252,11 +252,6 @@ typedef int TCGv_i64;
 #define TCGV_UNUSED_I64(x) x = MAKE_TCGV_I64(-1)
 
 /* call flags */
-#define TCG_CALL_TYPE_MASK      0x000f
-#define TCG_CALL_TYPE_STD       0x0000 /* standard C call */
-#define TCG_CALL_TYPE_REGPARM_1 0x0001 /* i386 style regparm call (1 reg) */
-#define TCG_CALL_TYPE_REGPARM_2 0x0002 /* i386 style regparm call (2 regs) */
-#define TCG_CALL_TYPE_REGPARM   0x0003 /* i386 style regparm call (3 regs) */
 /* A pure function only reads its arguments and TCG global variables
    and cannot raise exceptions. Hence a call to a pure function can be
    safely suppressed if the return value is not used. */
@@ -589,5 +584,5 @@ extern uint8_t code_gen_prologue[];
 /* TCG targets may use a different definition of tcg_qemu_tb_exec. */
 #if !defined(tcg_qemu_tb_exec)
 # define tcg_qemu_tb_exec(env, tb_ptr) \
-    ((tcg_target_ulong REGPARM (*)(void *, void *))code_gen_prologue)(env, tb_ptr)
+    ((tcg_target_ulong (*)(void *, void *))code_gen_prologue)(env, tb_ptr)
 #endif