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authorRichard Henderson <rth@twiddle.net>2015-09-18 23:43:05 -0700
committerRichard Henderson <rth@twiddle.net>2015-10-07 20:36:53 +1100
commit8163b74938d8b7d12e70597c4553dd0dc49443d5 (patch)
tree8cac7a8219d3e650cd0f9854fb62a73385383558 /tcg
parent04fe64000162c45d8974da9ca4d266f8d0e67eb7 (diff)
downloadqemu-arm-8163b74938d8b7d12e70597c4553dd0dc49443d5.tar.gz
tcg: Emit prologue to the beginning of code_gen_buffer
By putting the prologue at the end, we risk overwriting the prologue should our estimate of maximum TB size. Given the two different placements of the call to tcg_prologue_init, move the high water mark computation into tcg_prologue_init. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'tcg')
-rw-r--r--tcg/tcg.c35
1 files changed, 28 insertions, 7 deletions
diff --git a/tcg/tcg.c b/tcg/tcg.c
index d3693b17f2..56091087a4 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -363,17 +363,38 @@ void tcg_context_init(TCGContext *s)
void tcg_prologue_init(TCGContext *s)
{
- /* init global prologue and epilogue */
- s->code_buf = s->code_gen_prologue;
- s->code_ptr = s->code_buf;
+ size_t prologue_size, total_size;
+ void *buf0, *buf1;
+
+ /* Put the prologue at the beginning of code_gen_buffer. */
+ buf0 = s->code_gen_buffer;
+ s->code_ptr = buf0;
+ s->code_buf = buf0;
+ s->code_gen_prologue = buf0;
+
+ /* Generate the prologue. */
tcg_target_qemu_prologue(s);
- flush_icache_range((uintptr_t)s->code_buf, (uintptr_t)s->code_ptr);
+ buf1 = s->code_ptr;
+ flush_icache_range((uintptr_t)buf0, (uintptr_t)buf1);
+
+ /* Deduct the prologue from the buffer. */
+ prologue_size = tcg_current_code_size(s);
+ s->code_gen_ptr = buf1;
+ s->code_gen_buffer = buf1;
+ s->code_buf = buf1;
+ total_size = s->code_gen_buffer_size - prologue_size;
+ s->code_gen_buffer_size = total_size;
+
+ /* Compute a high-water mark, at which we voluntarily flush the
+ buffer and start over. */
+ s->code_gen_buffer_max_size = total_size - TCG_MAX_OP_SIZE * OPC_BUF_SIZE;
+
+ tcg_register_jit(s->code_gen_buffer, total_size);
#ifdef DEBUG_DISAS
if (qemu_loglevel_mask(CPU_LOG_TB_OUT_ASM)) {
- size_t size = tcg_current_code_size(s);
- qemu_log("PROLOGUE: [size=%zu]\n", size);
- log_disas(s->code_buf, size);
+ qemu_log("PROLOGUE: [size=%zu]\n", prologue_size);
+ log_disas(buf0, prologue_size);
qemu_log("\n");
qemu_log_flush();
}