commit 9da6079b2695dcffd8b18890db6cafdf4dc373db
author Richard Henderson <richard.henderson@linaro.org> Sat Nov 26 18:54:23 2022 -0800
committer Richard Henderson <richard.henderson@linaro.org> Tue Jan 17 10:08:55 2023 -1000
tree 40f2a3e7c03b3dc10b3bc3a38aca0e8641cea3c4
parent b7e4afbd9f2f9233a37e021f9e8cce472aecdd64

tcg: Add TranslationBlock.jmp_insn_offset

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.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

accel/tcg/cpu-exec.c

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 8927092..25c4b04 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -572,14 +572,13 @@
 
 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;
     }
 }
 

include/exec/exec-all.h

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index b4d09c8..54585a9 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -587,7 +587,8 @@
      */
 #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.

tcg/tcg.c

diff --git a/tcg/tcg.c b/tcg/tcg.c
index 4ac7086..af2af99 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -321,7 +321,7 @@
      * 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)
@@ -330,7 +330,7 @@
      * 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. */
@@ -4668,6 +4668,8 @@
     /* 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);