tcg/mips: Use the constant pool for 64-bit constants

During normal processing, the constant pool is accessible via
TCG_REG_TB.  During the prologue, it is accessible via TCG_REG_T9.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/mips/tcg-target.c.inc

@@ -25,6 +25,7 @@
  */
 
 #include "../tcg-ldst.c.inc"
+#include "../tcg-pool.c.inc"
 
 #if HOST_BIG_ENDIAN
 # define MIPS_BE  1
@@ -168,9 +169,18 @@ static bool reloc_pc16(tcg_insn_unit *src_rw, const tcg_insn_unit *target)
 static bool patch_reloc(tcg_insn_unit *code_ptr, int type,
                         intptr_t value, intptr_t addend)
 {
-    tcg_debug_assert(type == R_MIPS_PC16);
-    tcg_debug_assert(addend == 0);
-    return reloc_pc16(code_ptr, (const tcg_insn_unit *)value);
+    value += addend;
+    switch (type) {
+    case R_MIPS_PC16:
+        return reloc_pc16(code_ptr, (const tcg_insn_unit *)value);
+    case R_MIPS_16:
+        if (value != (int16_t)value) {
+            return false;
+        }
+        *code_ptr = deposit32(*code_ptr, 0, 16, value);
+        return true;
+    }
+    g_assert_not_reached();
 }
 
 #define TCG_CT_CONST_ZERO 0x100
@@ -486,6 +496,11 @@ static void tcg_out_nop(TCGContext *s)
     tcg_out32(s, 0);
 }
 
+static void tcg_out_nop_fill(tcg_insn_unit *p, int count)
+{
+    memset(p, 0, count * sizeof(tcg_insn_unit));
+}
+
 static void tcg_out_dsll(TCGContext *s, TCGReg rd, TCGReg rt, TCGArg sa)
 {
     tcg_out_opc_sa64(s, OPC_DSLL, OPC_DSLL32, rd, rt, sa);
@@ -543,8 +558,15 @@ static bool tcg_out_movi_two(TCGContext *s, TCGReg ret, tcg_target_long arg)
     return false;
 }
 
-static void tcg_out_movi(TCGContext *s, TCGType type,
-                         TCGReg ret, tcg_target_long arg)
+static void tcg_out_movi_pool(TCGContext *s, TCGReg ret,
+                              tcg_target_long arg, TCGReg tbreg)
+{
+    new_pool_label(s, arg, R_MIPS_16, s->code_ptr, tcg_tbrel_diff(s, NULL));
+    tcg_out_opc_imm(s, OPC_LD, ret, tbreg, 0);
+}
+
+static void tcg_out_movi_int(TCGContext *s, TCGType type, TCGReg ret,
+                             tcg_target_long arg, TCGReg tbreg)
 {
     if (TCG_TARGET_REG_BITS == 64 && type == TCG_TYPE_I32) {
         arg = (int32_t)arg;
@@ -554,18 +576,17 @@ static void tcg_out_movi(TCGContext *s, TCGType type,
     if (tcg_out_movi_two(s, ret, arg)) {
         return;
     }
+    assert(TCG_TARGET_REG_BITS == 64);
 
-    tcg_out_movi(s, TCG_TYPE_I32, ret, arg >> 31 >> 1);
-    if (arg & 0xffff0000ull) {
-        tcg_out_dsll(s, ret, ret, 16);
-        tcg_out_opc_imm(s, OPC_ORI, ret, ret, arg >> 16);
-        tcg_out_dsll(s, ret, ret, 16);
-    } else {
-        tcg_out_dsll(s, ret, ret, 32);
-    }
-    if (arg & 0xffff) {
-        tcg_out_opc_imm(s, OPC_ORI, ret, ret, arg & 0xffff);
-    }
+    /* Otherwise, put 64-bit constants into the constant pool. */
+    tcg_out_movi_pool(s, ret, arg, tbreg);
+}
+
+static void tcg_out_movi(TCGContext *s, TCGType type,
+                         TCGReg ret, tcg_target_long arg)
+{
+    TCGReg tbreg = TCG_TARGET_REG_BITS == 64 ? TCG_REG_TB : 0;
+    tcg_out_movi_int(s, type, ret, arg, tbreg);
 }
 
 static void tcg_out_ext8s(TCGContext *s, TCGType type, TCGReg rd, TCGReg rs)
@@ -2383,10 +2404,20 @@ static void tcg_target_qemu_prologue(TCGContext *s)
 
 #ifndef CONFIG_SOFTMMU
     if (guest_base != (int16_t)guest_base) {
-        tcg_out_movi(s, TCG_TYPE_PTR, TCG_GUEST_BASE_REG, guest_base);
+        /*
+         * The function call abi for n32 and n64 will have loaded $25 (t9)
+         * with the address of the prologue, so we can use that instead
+         * of TCG_REG_TB.
+         */
+#if TCG_TARGET_REG_BITS == 64 && !defined(__mips_abicalls)
+# error "Unknown mips abi"
+#endif
+        tcg_out_movi_int(s, TCG_TYPE_PTR, TCG_GUEST_BASE_REG, guest_base,
+                         TCG_TARGET_REG_BITS == 64 ? TCG_REG_T9 : 0);
         tcg_regset_set_reg(s->reserved_regs, TCG_GUEST_BASE_REG);
     }
 #endif
+
     if (TCG_TARGET_REG_BITS == 64) {
         tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_TB, tcg_target_call_iarg_regs[1]);
     }

tcg/mips/tcg-target.h

@@ -208,5 +208,6 @@ extern bool use_mips32r2_instructions;
 
 #define TCG_TARGET_DEFAULT_MO           0
 #define TCG_TARGET_NEED_LDST_LABELS
+#define TCG_TARGET_NEED_POOL_LABELS
 
 #endif