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[PATCH 22/22] tcg/riscv: Implement direct branch for goto_tb
From: |
Richard Henderson |
Subject: |
[PATCH 22/22] tcg/riscv: Implement direct branch for goto_tb |
Date: |
Mon, 5 Dec 2022 22:17:15 -0600 |
Now that tcg can handle direct and indirect goto_tb simultaneously,
we can optimistically leave space for a direct branch and fall back
to loading the pointer from the TB for an indirect branch.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
tcg/riscv/tcg-target.h | 5 +++++
tcg/riscv/tcg-target.c.inc | 19 +++++++++++++++++--
2 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/tcg/riscv/tcg-target.h b/tcg/riscv/tcg-target.h
index 56f7bc3346..a75c84f2a6 100644
--- a/tcg/riscv/tcg-target.h
+++ b/tcg/riscv/tcg-target.h
@@ -159,6 +159,11 @@ typedef enum {
#define TCG_TARGET_HAS_mulsh_i64 1
#endif
+<<<<<<< HEAD
+=======
+void tb_target_set_jmp_target(uintptr_t, uintptr_t, uintptr_t, uintptr_t);
+
+>>>>>>> 89ab294271 (tcg/riscv: Implement TCG_TARGET_HAS_direct_jump)
#define TCG_TARGET_DEFAULT_MO (0)
#define TCG_TARGET_NEED_LDST_LABELS
diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index de029d62b4..ee269ea157 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -1278,7 +1278,11 @@ static void tcg_out_exit_tb(TCGContext *s, uintptr_t a0)
static void tcg_out_goto_tb(TCGContext *s, int which)
{
- /* indirect jump method */
+ /* Direct branch will be patched by tb_target_set_jmp_target. */
+ set_jmp_insn_offset(s, which);
+ tcg_out32(s, OPC_NOP);
+
+ /* When branch is out of range, fall through to indirect. */
tcg_out_ld(s, TCG_TYPE_PTR, TCG_REG_TMP0, TCG_REG_ZERO,
get_jmp_target_addr(s, which));
tcg_out_opc_imm(s, OPC_JALR, TCG_REG_ZERO, TCG_REG_TMP0, 0);
@@ -1288,7 +1292,18 @@ static void tcg_out_goto_tb(TCGContext *s, int which)
void tb_target_set_jmp_target(const TranslationBlock *tb, int n,
uintptr_t jmp_rx, uintptr_t jmp_rw)
{
- /* Always indirect, nothing to do */
+ uintptr_t addr = tb->jmp_target_addr[n];
+ ptrdiff_t offset = addr - jmp_rx;
+ tcg_insn_unit insn;
+
+ /* Either directly branch, or fall through to indirect branch. */
+ if (offset == sextreg(offset, 0, 20)) {
+ insn = encode_uj(OPC_JAL, TCG_REG_ZERO, offset);
+ } else {
+ insn = OPC_NOP;
+ }
+ qatomic_set((uint32_t *)jmp_rw, insn);
+ flush_idcache_range(jmp_rx, jmp_rw, 4);
}
static void tcg_out_op(TCGContext *s, TCGOpcode opc,
--
2.34.1
- [PATCH 15/22] tcg: Remove TCG_TARGET_HAS_direct_jump, (continued)
- [PATCH 15/22] tcg: Remove TCG_TARGET_HAS_direct_jump, Richard Henderson, 2022/12/05
- [PATCH 16/22] tcg/aarch64: Reorg goto_tb implementation, Richard Henderson, 2022/12/05
- [PATCH 17/22] tcg/ppc: Reorg goto_tb implementation, Richard Henderson, 2022/12/05
- [PATCH 19/22] tcg/sparc64: Reorg goto_tb implementation, Richard Henderson, 2022/12/05
- [PATCH 18/22] tcg/sparc64: Remove USE_REG_TB, Richard Henderson, 2022/12/05
- [PATCH 20/22] tcg/arm: Implement direct branch for goto_tb, Richard Henderson, 2022/12/05
- [PATCH 21/22] tcg/riscv: Introduce OPC_NOP, Richard Henderson, 2022/12/05
- [PATCH 22/22] tcg/riscv: Implement direct branch for goto_tb,
Richard Henderson <=