[Qemu-devel] [PATCH v3 23/29] tcg-aarch64: Pass return address to load/store helpers directly.

[Richard Henderson <rth@twiddle.net>]

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 include/exec/exec-all.h  | 18 ------------------
 tcg/aarch64/tcg-target.c | 44 ++++++++++++++++++++++++++------------------
 2 files changed, 26 insertions(+), 36 deletions(-)

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 7510246..9a3ec05 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -320,24 +320,6 @@ extern uintptr_t tci_tb_ptr;
 
 #define GETPC()  (GETRA() - GETPC_ADJ)
 
-/* The LDST optimizations splits code generation into fast and slow path.
-   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(__aarch64__)
-#  define GETRA_LDST(RA)  tcg_getra_ldst(RA)
-static inline uintptr_t tcg_getra_ldst(uintptr_t ra)
-{
-    int32_t b;
-    ra += 4;                    /* skip one instruction */
-    b = *(int32_t *)ra;         /* load the branch insn */
-    b = (b << 6) >> (6 - 2);    /* extract the displacement */
-    ra += b;                    /* apply the displacement  */
-    return ra;
-}
-# endif
-#endif /* CONFIG_QEMU_LDST_OPTIMIZATION */
-
 /* ??? Delete these once they are no longer used.  */
 bool is_tcg_gen_code(uintptr_t pc_ptr);
 #ifdef GETRA_LDST
diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
index be74d2b..1d0db02 100644
--- a/tcg/aarch64/tcg-target.c
+++ b/tcg/aarch64/tcg-target.c
@@ -968,39 +968,46 @@ static inline void tcg_out_addsub2(TCGContext *s, int ext, TCGReg rl,
     }
 }
 
-static inline void tcg_out_nop(TCGContext *s)
-{
-    tcg_out32(s, 0xd503201f);
-}
-
 #ifdef CONFIG_SOFTMMU
-/* 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 inline void tcg_out_adr(TCGContext *s, TCGReg rd, tcg_target_long addr)
+{
+    addr -= (tcg_target_long)s->code_ptr;
+    assert(addr == sextract64(addr, 0, 21));
+    tcg_fmt_Rd_disp21(s, INSN_ADR, rd, addr);
+}
+
 static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
 {
     reloc_pc19(lb->label_ptr[0], (tcg_target_long)s->code_ptr);
     tcg_out_movr(s, 1, TCG_REG_X0, TCG_AREG0);
     tcg_out_movr(s, (TARGET_LONG_BITS == 64), TCG_REG_X1, lb->addrlo_reg);
     tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_X2, lb->mem_index);
+    tcg_out_adr(s, TCG_REG_X3, (uintptr_t)lb->raddr);
+
     tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP,
                  (tcg_target_long)qemu_ld_helpers[lb->opc & 3]);
     tcg_out_callr(s, TCG_REG_TMP);
+
     if (lb->opc & 0x04) {
         tcg_out_sxt(s, 1, lb->opc & 3, lb->datalo_reg, TCG_REG_X0);
     } else {
@@ -1018,11 +1025,12 @@ static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *lb)
     tcg_out_movr(s, (TARGET_LONG_BITS == 64), TCG_REG_X1, lb->addrlo_reg);
     tcg_out_movr(s, 1, TCG_REG_X2, lb->datalo_reg);
     tcg_out_movi(s, TCG_TYPE_I32, TCG_REG_X3, lb->mem_index);
+    tcg_out_adr(s, TCG_REG_X4, (uintptr_t)lb->raddr);
+
     tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP,
                  (tcg_target_long)qemu_st_helpers[lb->opc & 3]);
     tcg_out_callr(s, TCG_REG_TMP);
 
-    tcg_out_nop(s);
     tcg_out_goto(s, (tcg_target_long)lb->raddr);
 }
 
-- 
1.8.3.1