tcg/ppc: Fix CONFIG_TCG_PASS_AREG0 mode

Adjust the tcg_out_qemu_{ld,st}() slow paths to pass AREG0 in r3,
based on patches by malc.

Also adjust the registers clobbered, based on patch by Alex.
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Acked-by: NAlexander Graf <agraf@suse.de>
[AF: Do not hardcode r3 for AREG0, requested by Alex]
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

tcg/ppc/tcg-target.c

@@ -244,8 +244,18 @@ static int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str)
         tcg_regset_set32(ct->u.regs, 0, 0xffffffff);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R3);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R4);
+#ifdef CONFIG_TCG_PASS_AREG0
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R5);
+#if TARGET_LONG_BITS == 64
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R6);
+#ifdef TCG_TARGET_CALL_ALIGN_ARGS
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R7);
+#endif
+#endif
+#else /* !AREG0 */
 #if TARGET_LONG_BITS == 64
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R5);
+#endif
 #endif
         break;
     case 'K':                   /* qemu_st[8..32] constraint */
@@ -254,8 +264,18 @@ static int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str)
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R3);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R4);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R5);
+#ifdef CONFIG_TCG_PASS_AREG0
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R6);
+#if TARGET_LONG_BITS == 64
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R7);
+#ifdef TCG_TARGET_CALL_ALIGN_ARGS
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R8);
+#endif
+#endif
+#else /* !AREG0 */
 #if TARGET_LONG_BITS == 64
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R6);
+#endif
 #endif
         break;
     case 'M':                   /* qemu_st64 constraint */
@@ -266,6 +286,12 @@ static int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str)
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R5);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R6);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R7);
+#if defined(CONFIG_TCG_PASS_AREG0)
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R8);
+#ifdef TCG_TARGET_CALL_ALIGN_ARGS
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R9);
+#endif
+#endif
         break;
 #else
     case 'L':
@@ -512,7 +538,6 @@ static void tcg_out_call (TCGContext *s, tcg_target_long arg, int const_arg)
 #include "../../softmmu_defs.h"
 
 #ifdef CONFIG_TCG_PASS_AREG0
-#error CONFIG_TCG_PASS_AREG0 is not supported
 /* helper signature: helper_ld_mmu(CPUState *env, target_ulong addr,
    int mmu_idx) */
 static const void * const qemu_ld_helpers[4] = {
@@ -618,6 +643,9 @@ static void tcg_out_qemu_ld (TCGContext *s, const TCGArg *args, int opc)
 
     /* slow path */
     ir = 3;
+#ifdef CONFIG_TCG_PASS_AREG0
+    tcg_out_mov (s, TCG_TYPE_I32, ir++, TCG_AREG0);
+#endif
 #if TARGET_LONG_BITS == 32
     tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
 #else
@@ -817,6 +845,9 @@ static void tcg_out_qemu_st (TCGContext *s, const TCGArg *args, int opc)
 
     /* slow path */
     ir = 3;
+#ifdef CONFIG_TCG_PASS_AREG0
+    tcg_out_mov (s, TCG_TYPE_I32, ir++, TCG_AREG0);
+#endif
 #if TARGET_LONG_BITS == 32
     tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
 #else