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[PATCH v3 6/7] tcg/sparc: Add tcg_out_jmpl_const for better tail calls
From: |
Richard Henderson |
Subject: |
[PATCH v3 6/7] tcg/sparc: Add tcg_out_jmpl_const for better tail calls |
Date: |
Wed, 18 Aug 2021 10:46:01 -1000 |
Due to mapping changes, we now rarely place the code_gen_buffer
near the main executable. Which means that direct calls will
now rarely be in range.
So, always use indirect calls for tail calls, which allows us to
avoid clobbering %o7, and therefore we need not save and restore it.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
tcg/sparc/tcg-target.c.inc | 37 +++++++++++++++++++++++--------------
1 file changed, 23 insertions(+), 14 deletions(-)
diff --git a/tcg/sparc/tcg-target.c.inc b/tcg/sparc/tcg-target.c.inc
index b64760e736..8c1a0277d5 100644
--- a/tcg/sparc/tcg-target.c.inc
+++ b/tcg/sparc/tcg-target.c.inc
@@ -845,6 +845,19 @@ static void tcg_out_addsub2_i64(TCGContext *s, TCGReg rl,
TCGReg rh,
tcg_out_mov(s, TCG_TYPE_I64, rl, tmp);
}
+static void tcg_out_jmpl_const(TCGContext *s, const tcg_insn_unit *dest,
+ bool in_prologue, bool tail_call)
+{
+ uintptr_t desti = (uintptr_t)dest;
+
+ /* Be careful not to clobber %o7 for a tail call. */
+ tcg_out_movi_int(s, TCG_TYPE_PTR, TCG_REG_T1,
+ desti & ~0xfff, in_prologue,
+ tail_call ? TCG_REG_G2 : TCG_REG_O7);
+ tcg_out_arithi(s, tail_call ? TCG_REG_G0 : TCG_REG_O7,
+ TCG_REG_T1, desti & 0xfff, JMPL);
+}
+
static void tcg_out_call_nodelay(TCGContext *s, const tcg_insn_unit *dest,
bool in_prologue)
{
@@ -853,10 +866,7 @@ static void tcg_out_call_nodelay(TCGContext *s, const
tcg_insn_unit *dest,
if (disp == (int32_t)disp) {
tcg_out32(s, CALL | (uint32_t)disp >> 2);
} else {
- uintptr_t desti = (uintptr_t)dest;
- tcg_out_movi_int(s, TCG_TYPE_PTR, TCG_REG_T1,
- desti & ~0xfff, in_prologue, TCG_REG_O7);
- tcg_out_arithi(s, TCG_REG_O7, TCG_REG_T1, desti & 0xfff, JMPL);
+ tcg_out_jmpl_const(s, dest, in_prologue, false);
}
}
@@ -947,11 +957,10 @@ static void build_trampolines(TCGContext *s)
/* Set the retaddr operand. */
tcg_out_mov(s, TCG_TYPE_PTR, ra, TCG_REG_O7);
- /* Set the env operand. */
- tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_O0, TCG_AREG0);
/* Tail call. */
- tcg_out_call_nodelay(s, qemu_ld_helpers[i], true);
- tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_O7, ra);
+ tcg_out_jmpl_const(s, qemu_ld_helpers[i], true, true);
+ /* delay slot -- set the env argument */
+ tcg_out_mov_delay(s, TCG_REG_O0, TCG_AREG0);
}
for (i = 0; i < ARRAY_SIZE(qemu_st_helpers); ++i) {
@@ -993,14 +1002,14 @@ static void build_trampolines(TCGContext *s)
if (ra >= TCG_REG_O6) {
tcg_out_st(s, TCG_TYPE_PTR, TCG_REG_O7, TCG_REG_CALL_STACK,
TCG_TARGET_CALL_STACK_OFFSET);
- ra = TCG_REG_G1;
+ } else {
+ tcg_out_mov(s, TCG_TYPE_PTR, ra, TCG_REG_O7);
}
- tcg_out_mov(s, TCG_TYPE_PTR, ra, TCG_REG_O7);
- /* Set the env operand. */
- tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_O0, TCG_AREG0);
+
/* Tail call. */
- tcg_out_call_nodelay(s, qemu_st_helpers[i], true);
- tcg_out_mov(s, TCG_TYPE_PTR, TCG_REG_O7, ra);
+ tcg_out_jmpl_const(s, qemu_st_helpers[i], true, true);
+ /* delay slot -- set the env argument */
+ tcg_out_mov_delay(s, TCG_REG_O0, TCG_AREG0);
}
}
#endif
--
2.25.1
- [PATCH v3 0/7] tcg/sparc: Unaligned access and other cleanup, Richard Henderson, 2021/08/18
- [PATCH v3 1/7] tcg/sparc: Drop inline markers, Richard Henderson, 2021/08/18
- [PATCH v3 3/7] tcg/sparc: Add scratch argument to tcg_out_movi_int, Richard Henderson, 2021/08/18
- [PATCH v3 4/7] tcg/sparc: Improve code gen for shifted 32-bit constants, Richard Henderson, 2021/08/18
- [PATCH v3 5/7] tcg/sparc: Use the constant pool for 64-bit constants, Richard Henderson, 2021/08/18
- [PATCH v3 2/7] tcg/sparc: Introduce tcg_out_mov_delay, Richard Henderson, 2021/08/18
- [PATCH v3 6/7] tcg/sparc: Add tcg_out_jmpl_const for better tail calls,
Richard Henderson <=
- [PATCH v3 7/7] tcg/sparc: Support unaligned access for user-only, Richard Henderson, 2021/08/18