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| author | Richard Henderson <richard.henderson@linaro.org> | 2022-11-27 01:11:56 -0800 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2023-01-17 22:36:17 +0000 |
| commit | 493c9b19a7fb7f387c4fcf57d3836504d5242bf5 (patch) | |
| tree | 35be2ec7214b6880570fb633070a24ae7031e62e /tcg | |
| parent | 9ae958e4d7504f87c2ecd5915d8c3ede7007f2e2 (diff) | |
| download | qemu-493c9b19a7fb7f387c4fcf57d3836504d5242bf5.zip qemu-493c9b19a7fb7f387c4fcf57d3836504d5242bf5.tar.gz qemu-493c9b19a7fb7f387c4fcf57d3836504d5242bf5.tar.bz2 | |
tcg/riscv: Implement direct branch for goto_tb
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.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'tcg')
| -rw-r--r-- | tcg/riscv/tcg-target.c.inc | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc index 82ca864..fc0edd8 100644 --- a/tcg/riscv/tcg-target.c.inc +++ b/tcg/riscv/tcg-target.c.inc @@ -1303,7 +1303,11 @@ 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_JAL); + + /* 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); @@ -1313,7 +1317,18 @@ 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, |