[11/22] tcg: Add TranslationBlock.jmp_insn_offset

Commit Message

Richard Henderson Dec. 6, 2022, 4:17 a.m. UTC

Stop overloading jmp_target_arg for both offset and address,
depending on TCG_TARGET_HAS_direct_jump.  Instead, add a new
field to hold the jump insn offset and always set the target
address in jmp_target_addr[].  This will allow a tcg backend
to use either direct or indirect depending on displacement.

Signed-off-by: Richard Henderson <[e-mail]>
---
 include/exec/exec-all.h | 3 ++-
 accel/tcg/cpu-exec.c    | 5 ++---
 tcg/tcg.c               | 6 ++++--
 3 files changed, 8 insertions(+), 6 deletions(-)

Patch

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 7566ad9e7f..bb01508b4b 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -577,7 +577,8 @@  struct TranslationBlock {
      */
 #define TB_JMP_OFFSET_INVALID 0xffff /* indicates no jump generated */
     uint16_t jmp_reset_offset[2]; /* offset of original jump target */
-    uintptr_t jmp_target_arg[2];  /* target address or offset */
+    uint16_t jmp_insn_offset[2];  /* offset of direct jump insn */
+    uintptr_t jmp_target_addr[2]; /* target address */
 
     /*
      * Each TB has a NULL-terminated list (jmp_list_head) of incoming jumps.
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 356fe348de..a87fbf74f4 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -572,14 +572,13 @@  void cpu_exec_step_atomic(CPUState *cpu)
 
 void tb_set_jmp_target(TranslationBlock *tb, int n, uintptr_t addr)
 {
+    tb->jmp_target_addr[n] = addr;
     if (TCG_TARGET_HAS_direct_jump) {
-        uintptr_t offset = tb->jmp_target_arg[n];
+        uintptr_t offset = tb->jmp_insn_offset[n];
         uintptr_t tc_ptr = (uintptr_t)tb->tc.ptr;
         uintptr_t jmp_rx = tc_ptr + offset;
         uintptr_t jmp_rw = jmp_rx - tcg_splitwx_diff;
         tb_target_set_jmp_target(tc_ptr, jmp_rx, jmp_rw, addr);
-    } else {
-        tb->jmp_target_arg[n] = addr;
     }
 }
 
diff --git a/tcg/tcg.c b/tcg/tcg.c
index c7ad46ff45..c103dd0037 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -328,7 +328,7 @@  static void G_GNUC_UNUSED set_jmp_insn_offset(TCGContext *s, int which)
      * tcg_gen_code, where we bound tcg_current_code_size to UINT16_MAX.
      */
     tcg_debug_assert(TCG_TARGET_HAS_direct_jump);
-    s->gen_tb->jmp_target_arg[which] = tcg_current_code_size(s);
+    s->gen_tb->jmp_insn_offset[which] = tcg_current_code_size(s);
 }
 
 static uintptr_t G_GNUC_UNUSED get_jmp_target_addr(TCGContext *s, int which)
@@ -337,7 +337,7 @@  static uintptr_t G_GNUC_UNUSED get_jmp_target_addr(TCGContext *s, int which)
      * Return the read-execute version of the pointer, for the benefit
      * of any pc-relative addressing mode.
      */
-    return (uintptr_t)tcg_splitwx_to_rx(s->gen_tb->jmp_target_arg + which);
+    return (uintptr_t)tcg_splitwx_to_rx(&s->gen_tb->jmp_target_addr[which]);
 }
 
 /* Signal overflow, starting over with fewer guest insns. */
@@ -4252,6 +4252,8 @@  int tcg_gen_code(TCGContext *s, TranslationBlock *tb, target_ulong pc_start)
     /* Initialize goto_tb jump offsets. */
     tb->jmp_reset_offset[0] = TB_JMP_OFFSET_INVALID;
     tb->jmp_reset_offset[1] = TB_JMP_OFFSET_INVALID;
+    tb->jmp_insn_offset[0] = TB_JMP_OFFSET_INVALID;
+    tb->jmp_insn_offset[1] = TB_JMP_OFFSET_INVALID;
 
     tcg_reg_alloc_start(s);