tcg: Optimize qemu_ld/st by generating slow paths at the end of a block
Add optimized TCG qemu_ld/st generation which locates the code of TLB miss
cases at the end of a block after generating the other IRs.
Currently, this optimization supports only i386 and x86_64 hosts.
Signed-off-by: Yeongkyoon Lee <yeongkyoon.lee@samsung.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
index e45a5a0..6f3ad3c 100644
--- a/tcg/i386/tcg-target.c
+++ b/tcg/i386/tcg-target.c
@@ -1002,6 +1002,17 @@
helper_stq_mmu,
};
+static void add_qemu_ldst_label(TCGContext *s,
+ int is_ld,
+ int opc,
+ int data_reg,
+ int data_reg2,
+ int addrlo_reg,
+ int addrhi_reg,
+ int mem_index,
+ uint8_t *raddr,
+ uint8_t **label_ptr);
+
/* Perform the TLB load and compare.
Inputs:
@@ -1060,19 +1071,19 @@
tcg_out_mov(s, type, r1, addrlo);
- /* jne label1 */
- tcg_out8(s, OPC_JCC_short + JCC_JNE);
+ /* jne slow_path */
+ tcg_out_opc(s, OPC_JCC_long + JCC_JNE, 0, 0, 0);
label_ptr[0] = s->code_ptr;
- s->code_ptr++;
+ s->code_ptr += 4;
if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
/* cmp 4(r0), addrhi */
tcg_out_modrm_offset(s, OPC_CMP_GvEv, args[addrlo_idx+1], r0, 4);
- /* jne label1 */
- tcg_out8(s, OPC_JCC_short + JCC_JNE);
+ /* jne slow_path */
+ tcg_out_opc(s, OPC_JCC_long + JCC_JNE, 0, 0, 0);
label_ptr[1] = s->code_ptr;
- s->code_ptr++;
+ s->code_ptr += 4;
}
/* TLB Hit. */
@@ -1193,10 +1204,7 @@
int addrlo_idx;
#if defined(CONFIG_SOFTMMU)
int mem_index, s_bits;
-#if TCG_TARGET_REG_BITS == 32
- int stack_adjust;
-#endif
- uint8_t *label_ptr[3];
+ uint8_t *label_ptr[2];
#endif
data_reg = args[0];
@@ -1216,87 +1224,17 @@
/* TLB Hit. */
tcg_out_qemu_ld_direct(s, data_reg, data_reg2, TCG_REG_L1, 0, 0, opc);
- /* jmp label2 */
- tcg_out8(s, OPC_JMP_short);
- label_ptr[2] = s->code_ptr;
- s->code_ptr++;
-
- /* TLB Miss. */
-
- /* label1: */
- *label_ptr[0] = s->code_ptr - label_ptr[0] - 1;
- if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
- *label_ptr[1] = s->code_ptr - label_ptr[1] - 1;
- }
-
- /* XXX: move that code at the end of the TB */
-#if TCG_TARGET_REG_BITS == 32
- tcg_out_pushi(s, mem_index);
- stack_adjust = 4;
- if (TARGET_LONG_BITS == 64) {
- tcg_out_push(s, args[addrlo_idx + 1]);
- stack_adjust += 4;
- }
- tcg_out_push(s, args[addrlo_idx]);
- stack_adjust += 4;
- tcg_out_push(s, TCG_AREG0);
- stack_adjust += 4;
-#else
- tcg_out_mov(s, TCG_TYPE_I64, tcg_target_call_iarg_regs[0], TCG_AREG0);
- /* The second argument is already loaded with addrlo. */
- tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[2], mem_index);
-#endif
-
- tcg_out_calli(s, (tcg_target_long)qemu_ld_helpers[s_bits]);
-
-#if TCG_TARGET_REG_BITS == 32
- if (stack_adjust == (TCG_TARGET_REG_BITS / 8)) {
- /* Pop and discard. This is 2 bytes smaller than the add. */
- tcg_out_pop(s, TCG_REG_ECX);
- } else if (stack_adjust != 0) {
- tcg_out_addi(s, TCG_REG_CALL_STACK, stack_adjust);
- }
-#endif
-
- switch(opc) {
- case 0 | 4:
- tcg_out_ext8s(s, data_reg, TCG_REG_EAX, P_REXW);
- break;
- case 1 | 4:
- tcg_out_ext16s(s, data_reg, TCG_REG_EAX, P_REXW);
- break;
- case 0:
- tcg_out_ext8u(s, data_reg, TCG_REG_EAX);
- break;
- case 1:
- tcg_out_ext16u(s, data_reg, TCG_REG_EAX);
- break;
- case 2:
- tcg_out_mov(s, TCG_TYPE_I32, data_reg, TCG_REG_EAX);
- break;
-#if TCG_TARGET_REG_BITS == 64
- case 2 | 4:
- tcg_out_ext32s(s, data_reg, TCG_REG_EAX);
- break;
-#endif
- case 3:
- if (TCG_TARGET_REG_BITS == 64) {
- tcg_out_mov(s, TCG_TYPE_I64, data_reg, TCG_REG_RAX);
- } else if (data_reg == TCG_REG_EDX) {
- /* xchg %edx, %eax */
- tcg_out_opc(s, OPC_XCHG_ax_r32 + TCG_REG_EDX, 0, 0, 0);
- tcg_out_mov(s, TCG_TYPE_I32, data_reg2, TCG_REG_EAX);
- } else {
- tcg_out_mov(s, TCG_TYPE_I32, data_reg, TCG_REG_EAX);
- tcg_out_mov(s, TCG_TYPE_I32, data_reg2, TCG_REG_EDX);
- }
- break;
- default:
- tcg_abort();
- }
-
- /* label2: */
- *label_ptr[2] = s->code_ptr - label_ptr[2] - 1;
+ /* Record the current context of a load into ldst label */
+ add_qemu_ldst_label(s,
+ 1,
+ opc,
+ data_reg,
+ data_reg2,
+ args[addrlo_idx],
+ args[addrlo_idx + 1],
+ mem_index,
+ s->code_ptr,
+ label_ptr);
#else
{
int32_t offset = GUEST_BASE;
@@ -1393,8 +1331,7 @@
int addrlo_idx;
#if defined(CONFIG_SOFTMMU)
int mem_index, s_bits;
- int stack_adjust;
- uint8_t *label_ptr[3];
+ uint8_t *label_ptr[2];
#endif
data_reg = args[0];
@@ -1414,57 +1351,17 @@
/* TLB Hit. */
tcg_out_qemu_st_direct(s, data_reg, data_reg2, TCG_REG_L1, 0, 0, opc);
- /* jmp label2 */
- tcg_out8(s, OPC_JMP_short);
- label_ptr[2] = s->code_ptr;
- s->code_ptr++;
-
- /* TLB Miss. */
-
- /* label1: */
- *label_ptr[0] = s->code_ptr - label_ptr[0] - 1;
- if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
- *label_ptr[1] = s->code_ptr - label_ptr[1] - 1;
- }
-
- /* XXX: move that code at the end of the TB */
-#if TCG_TARGET_REG_BITS == 32
- tcg_out_pushi(s, mem_index);
- stack_adjust = 4;
- if (opc == 3) {
- tcg_out_push(s, data_reg2);
- stack_adjust += 4;
- }
- tcg_out_push(s, data_reg);
- stack_adjust += 4;
- if (TARGET_LONG_BITS == 64) {
- tcg_out_push(s, args[addrlo_idx + 1]);
- stack_adjust += 4;
- }
- tcg_out_push(s, args[addrlo_idx]);
- stack_adjust += 4;
- tcg_out_push(s, TCG_AREG0);
- stack_adjust += 4;
-#else
- tcg_out_mov(s, TCG_TYPE_I64, tcg_target_call_iarg_regs[0], TCG_AREG0);
- /* The second argument is already loaded with addrlo. */
- tcg_out_mov(s, (opc == 3 ? TCG_TYPE_I64 : TCG_TYPE_I32),
- tcg_target_call_iarg_regs[2], data_reg);
- tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[3], mem_index);
- stack_adjust = 0;
-#endif
-
- tcg_out_calli(s, (tcg_target_long)qemu_st_helpers[s_bits]);
-
- if (stack_adjust == (TCG_TARGET_REG_BITS / 8)) {
- /* Pop and discard. This is 2 bytes smaller than the add. */
- tcg_out_pop(s, TCG_REG_ECX);
- } else if (stack_adjust != 0) {
- tcg_out_addi(s, TCG_REG_CALL_STACK, stack_adjust);
- }
-
- /* label2: */
- *label_ptr[2] = s->code_ptr - label_ptr[2] - 1;
+ /* Record the current context of a store into ldst label */
+ add_qemu_ldst_label(s,
+ 0,
+ opc,
+ data_reg,
+ data_reg2,
+ args[addrlo_idx],
+ args[addrlo_idx + 1],
+ mem_index,
+ s->code_ptr,
+ label_ptr);
#else
{
int32_t offset = GUEST_BASE;
@@ -1491,6 +1388,261 @@
#endif
}
+#if defined(CONFIG_SOFTMMU)
+/*
+ * Record the context of a call to the out of line helper code for the slow path
+ * for a load or store, so that we can later generate the correct helper code
+ */
+static void add_qemu_ldst_label(TCGContext *s,
+ int is_ld,
+ int opc,
+ int data_reg,
+ int data_reg2,
+ int addrlo_reg,
+ int addrhi_reg,
+ int mem_index,
+ uint8_t *raddr,
+ uint8_t **label_ptr)
+{
+ int idx;
+ TCGLabelQemuLdst *label;
+
+ if (s->nb_qemu_ldst_labels >= TCG_MAX_QEMU_LDST) {
+ tcg_abort();
+ }
+
+ idx = s->nb_qemu_ldst_labels++;
+ label = (TCGLabelQemuLdst *)&s->qemu_ldst_labels[idx];
+ label->is_ld = is_ld;
+ label->opc = opc;
+ label->datalo_reg = data_reg;
+ label->datahi_reg = data_reg2;
+ label->addrlo_reg = addrlo_reg;
+ label->addrhi_reg = addrhi_reg;
+ label->mem_index = mem_index;
+ label->raddr = raddr;
+ label->label_ptr[0] = label_ptr[0];
+ if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
+ label->label_ptr[1] = label_ptr[1];
+ }
+}
+
+/*
+ * Generate code for the slow path for a load at the end of block
+ */
+static void tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
+{
+ int s_bits;
+ int opc = label->opc;
+ int mem_index = label->mem_index;
+#if TCG_TARGET_REG_BITS == 32
+ int stack_adjust;
+ int addrlo_reg = label->addrlo_reg;
+ int addrhi_reg = label->addrhi_reg;
+#endif
+ int data_reg = label->datalo_reg;
+ int data_reg2 = label->datahi_reg;
+ uint8_t *raddr = label->raddr;
+ uint8_t **label_ptr = &label->label_ptr[0];
+
+ s_bits = opc & 3;
+
+ /* resolve label address */
+ *(uint32_t *)label_ptr[0] = (uint32_t)(s->code_ptr - label_ptr[0] - 4);
+ if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
+ *(uint32_t *)label_ptr[1] = (uint32_t)(s->code_ptr - label_ptr[1] - 4);
+ }
+
+#if TCG_TARGET_REG_BITS == 32
+ tcg_out_pushi(s, mem_index);
+ stack_adjust = 4;
+ if (TARGET_LONG_BITS == 64) {
+ tcg_out_push(s, addrhi_reg);
+ stack_adjust += 4;
+ }
+ tcg_out_push(s, addrlo_reg);
+ stack_adjust += 4;
+ tcg_out_push(s, TCG_AREG0);
+ stack_adjust += 4;
+#else
+ tcg_out_mov(s, TCG_TYPE_I64, tcg_target_call_iarg_regs[0], TCG_AREG0);
+ /* The second argument is already loaded with addrlo. */
+ tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[2], mem_index);
+#endif
+
+ /* Code generation of qemu_ld/st's slow path calling MMU helper
+
+ PRE_PROC ...
+ call MMU helper
+ jmp POST_PROC (2b) : short forward jump <- GETRA()
+ jmp next_code (5b) : dummy long backward jump which is never executed
+ POST_PROC ... : do post-processing <- GETRA() + 7
+ jmp next_code : jump to the code corresponding to next IR of qemu_ld/st
+ */
+
+ tcg_out_calli(s, (tcg_target_long)qemu_ld_helpers[s_bits]);
+
+ /* Jump to post-processing code */
+ tcg_out8(s, OPC_JMP_short);
+ tcg_out8(s, 5);
+ /* Dummy backward jump having information of fast path'pc for MMU helpers */
+ tcg_out8(s, OPC_JMP_long);
+ *(int32_t *)s->code_ptr = (int32_t)(raddr - s->code_ptr - 4);
+ s->code_ptr += 4;
+
+#if TCG_TARGET_REG_BITS == 32
+ if (stack_adjust == (TCG_TARGET_REG_BITS / 8)) {
+ /* Pop and discard. This is 2 bytes smaller than the add. */
+ tcg_out_pop(s, TCG_REG_ECX);
+ } else if (stack_adjust != 0) {
+ tcg_out_addi(s, TCG_REG_CALL_STACK, stack_adjust);
+ }
+#endif
+
+ switch(opc) {
+ case 0 | 4:
+ tcg_out_ext8s(s, data_reg, TCG_REG_EAX, P_REXW);
+ break;
+ case 1 | 4:
+ tcg_out_ext16s(s, data_reg, TCG_REG_EAX, P_REXW);
+ break;
+ case 0:
+ tcg_out_ext8u(s, data_reg, TCG_REG_EAX);
+ break;
+ case 1:
+ tcg_out_ext16u(s, data_reg, TCG_REG_EAX);
+ break;
+ case 2:
+ tcg_out_mov(s, TCG_TYPE_I32, data_reg, TCG_REG_EAX);
+ break;
+#if TCG_TARGET_REG_BITS == 64
+ case 2 | 4:
+ tcg_out_ext32s(s, data_reg, TCG_REG_EAX);
+ break;
+#endif
+ case 3:
+ if (TCG_TARGET_REG_BITS == 64) {
+ tcg_out_mov(s, TCG_TYPE_I64, data_reg, TCG_REG_RAX);
+ } else if (data_reg == TCG_REG_EDX) {
+ /* xchg %edx, %eax */
+ tcg_out_opc(s, OPC_XCHG_ax_r32 + TCG_REG_EDX, 0, 0, 0);
+ tcg_out_mov(s, TCG_TYPE_I32, data_reg2, TCG_REG_EAX);
+ } else {
+ tcg_out_mov(s, TCG_TYPE_I32, data_reg, TCG_REG_EAX);
+ tcg_out_mov(s, TCG_TYPE_I32, data_reg2, TCG_REG_EDX);
+ }
+ break;
+ default:
+ tcg_abort();
+ }
+
+ /* Jump to the code corresponding to next IR of qemu_st */
+ tcg_out_jmp(s, (tcg_target_long)raddr);
+}
+
+/*
+ * Generate code for the slow path for a store at the end of block
+ */
+static void tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *label)
+{
+ int s_bits;
+ int stack_adjust;
+ int opc = label->opc;
+ int mem_index = label->mem_index;
+ int data_reg = label->datalo_reg;
+#if TCG_TARGET_REG_BITS == 32
+ int data_reg2 = label->datahi_reg;
+ int addrlo_reg = label->addrlo_reg;
+ int addrhi_reg = label->addrhi_reg;
+#endif
+ uint8_t *raddr = label->raddr;
+ uint8_t **label_ptr = &label->label_ptr[0];
+
+ s_bits = opc & 3;
+
+ /* resolve label address */
+ *(uint32_t *)label_ptr[0] = (uint32_t)(s->code_ptr - label_ptr[0] - 4);
+ if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
+ *(uint32_t *)label_ptr[1] = (uint32_t)(s->code_ptr - label_ptr[1] - 4);
+ }
+
+#if TCG_TARGET_REG_BITS == 32
+ tcg_out_pushi(s, mem_index);
+ stack_adjust = 4;
+ if (opc == 3) {
+ tcg_out_push(s, data_reg2);
+ stack_adjust += 4;
+ }
+ tcg_out_push(s, data_reg);
+ stack_adjust += 4;
+ if (TARGET_LONG_BITS == 64) {
+ tcg_out_push(s, addrhi_reg);
+ stack_adjust += 4;
+ }
+ tcg_out_push(s, addrlo_reg);
+ stack_adjust += 4;
+ tcg_out_push(s, TCG_AREG0);
+ stack_adjust += 4;
+#else
+ tcg_out_mov(s, TCG_TYPE_I64, tcg_target_call_iarg_regs[0], TCG_AREG0);
+ /* The second argument is already loaded with addrlo. */
+ tcg_out_mov(s, (opc == 3 ? TCG_TYPE_I64 : TCG_TYPE_I32),
+ tcg_target_call_iarg_regs[2], data_reg);
+ tcg_out_movi(s, TCG_TYPE_I32, tcg_target_call_iarg_regs[3], mem_index);
+ stack_adjust = 0;
+#endif
+
+ /* Code generation of qemu_ld/st's slow path calling MMU helper
+
+ PRE_PROC ...
+ call MMU helper
+ jmp POST_PROC (2b) : short forward jump <- GETRA()
+ jmp next_code (5b) : dummy long backward jump which is never executed
+ POST_PROC ... : do post-processing <- GETRA() + 7
+ jmp next_code : jump to the code corresponding to next IR of qemu_ld/st
+ */
+
+ tcg_out_calli(s, (tcg_target_long)qemu_st_helpers[s_bits]);
+
+ /* Jump to post-processing code */
+ tcg_out8(s, OPC_JMP_short);
+ tcg_out8(s, 5);
+ /* Dummy backward jump having information of fast path'pc for MMU helpers */
+ tcg_out8(s, OPC_JMP_long);
+ *(int32_t *)s->code_ptr = (int32_t)(raddr - s->code_ptr - 4);
+ s->code_ptr += 4;
+
+ if (stack_adjust == (TCG_TARGET_REG_BITS / 8)) {
+ /* Pop and discard. This is 2 bytes smaller than the add. */
+ tcg_out_pop(s, TCG_REG_ECX);
+ } else if (stack_adjust != 0) {
+ tcg_out_addi(s, TCG_REG_CALL_STACK, stack_adjust);
+ }
+
+ /* Jump to the code corresponding to next IR of qemu_st */
+ tcg_out_jmp(s, (tcg_target_long)raddr);
+}
+
+/*
+ * Generate TB finalization at the end of block
+ */
+void tcg_out_tb_finalize(TCGContext *s)
+{
+ int i;
+ TCGLabelQemuLdst *label;
+
+ /* qemu_ld/st slow paths */
+ for (i = 0; i < s->nb_qemu_ldst_labels; i++) {
+ label = (TCGLabelQemuLdst *)&s->qemu_ldst_labels[i];
+ if (label->is_ld) {
+ tcg_out_qemu_ld_slow_path(s, label);
+ } else {
+ tcg_out_qemu_st_slow_path(s, label);
+ }
+ }
+}
+#endif /* CONFIG_SOFTMMU */
+
static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
const TCGArg *args, const int *const_args)
{
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 1133438..42052db 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -299,6 +299,14 @@
gen_opc_ptr = gen_opc_buf;
gen_opparam_ptr = gen_opparam_buf;
+
+#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
+ /* Initialize qemu_ld/st labels to assist code generation at the end of TB
+ for TLB miss cases at the end of TB */
+ s->qemu_ldst_labels = tcg_malloc(sizeof(TCGLabelQemuLdst) *
+ TCG_MAX_QEMU_LDST);
+ s->nb_qemu_ldst_labels = 0;
+#endif
}
static inline void tcg_temp_alloc(TCGContext *s, int n)
@@ -2314,6 +2322,10 @@
#endif
}
the_end:
+#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
+ /* Generate TB finalization at the end of block */
+ tcg_out_tb_finalize(s);
+#endif
return -1;
}
diff --git a/tcg/tcg.h b/tcg/tcg.h
index a6c9256..c2ae873 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -188,6 +188,24 @@
are aliases for target_ulong and host pointer sized values respectively.
*/
+#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
+/* Macros/structures for qemu_ld/st IR code optimization:
+ TCG_MAX_HELPER_LABELS is defined as same as OPC_BUF_SIZE in exec-all.h. */
+#define TCG_MAX_QEMU_LDST 640
+
+typedef struct TCGLabelQemuLdst {
+ int is_ld:1; /* qemu_ld: 1, qemu_st: 0 */
+ int opc:4;
+ int addrlo_reg; /* reg index for low word of guest virtual addr */
+ int addrhi_reg; /* reg index for high word of guest virtual addr */
+ int datalo_reg; /* reg index for low word to be loaded or stored */
+ int datahi_reg; /* reg index for high word to be loaded or stored */
+ int mem_index; /* soft MMU memory index */
+ uint8_t *raddr; /* gen code addr of the next IR of qemu_ld/st IR */
+ uint8_t *label_ptr[2]; /* label pointers to be updated */
+} TCGLabelQemuLdst;
+#endif
+
#ifdef CONFIG_DEBUG_TCG
#define DEBUG_TCGV 1
#endif
@@ -431,6 +449,13 @@
int temps_in_use;
int goto_tb_issue_mask;
#endif
+
+#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
+ /* labels info for qemu_ld/st IRs
+ The labels help to generate TLB miss case codes at the end of TB */
+ TCGLabelQemuLdst *qemu_ldst_labels;
+ int nb_qemu_ldst_labels;
+#endif
};
extern TCGContext tcg_ctx;
@@ -634,3 +659,8 @@
#endif
void tcg_register_jit(void *buf, size_t buf_size);
+
+#if defined(CONFIG_QEMU_LDST_OPTIMIZATION) && defined(CONFIG_SOFTMMU)
+/* Generate TB finalization at the end of block */
+void tcg_out_tb_finalize(TCGContext *s);
+#endif
