This commit adds initialization of TCG_AREG0 and TCG_REG_CALL_STACK at the
beginning of each TB. The CPUArchState struct and the stack array are passed
from the caller via the WasmContext structure. The BLOCK_IDX variable is
initialized to 0 as TB execution begins at the first block.

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
---
 tcg/wasm.h                | 10 ++++++++++
 tcg/wasm/tcg-target.c.inc | 19 +++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/tcg/wasm.h b/tcg/wasm.h
index fba8b16503..91567bb964 100644
--- a/tcg/wasm.h
+++ b/tcg/wasm.h
@@ -22,6 +22,16 @@ struct WasmContext {
      * Buffer to store 128bit return value on call.
      */
     void *buf128;
+
+    /*
+     * Pointer to the CPUArchState struct.
+     */
+    CPUArchState *env;
+
+    /*
+     * Pointer to a stack array.
+     */
+    uint64_t *stack;
 };
 
 #endif
diff --git a/tcg/wasm/tcg-target.c.inc b/tcg/wasm/tcg-target.c.inc
index 6b8df4e9d7..0182d072ca 100644
--- a/tcg/wasm/tcg-target.c.inc
+++ b/tcg/wasm/tcg-target.c.inc
@@ -2419,11 +2419,30 @@ static inline void tcg_target_qemu_prologue(TCGContext *s)
 
 static void tcg_out_tb_start(TCGContext *s)
 {
+    intptr_t ofs;
+
     init_sub_buf();
     init_blocks();
     init_label_info();
     init_helpers();
 
+    /* Initialize fundamental registers */
+    tcg_wasm_out_op_idx(s, OPC_GLOBAL_GET, REG_IDX(TCG_AREG0));
+    tcg_wasm_out_op(s, OPC_I64_EQZ);
+    tcg_wasm_out_op_block(s, OPC_IF, BLOCK_NORET);
+
+    ofs = tcg_wasm_out_get_ctx(s, CTX_OFFSET(env));
+    tcg_wasm_out_op_ldst(s, OPC_I64_LOAD, 0, ofs);
+    tcg_wasm_out_op_idx(s, OPC_GLOBAL_SET, REG_IDX(TCG_AREG0));
+
+    ofs = tcg_wasm_out_get_ctx(s, CTX_OFFSET(stack));
+    tcg_wasm_out_op_ldst(s, OPC_I64_LOAD, 0, ofs);
+    tcg_wasm_out_op_idx(s, OPC_GLOBAL_SET, REG_IDX(TCG_REG_CALL_STACK));
+    tcg_wasm_out_op(s, OPC_END);
+
+    tcg_wasm_out_op_const(s, OPC_I64_CONST, 0);
+    tcg_wasm_out_op_idx(s, OPC_GLOBAL_SET, BLOCK_IDX);
+
     tcg_wasm_out_op_block(s, OPC_LOOP, BLOCK_NORET);
     tcg_wasm_out_op_idx(s, OPC_GLOBAL_GET, BLOCK_IDX);
     tcg_wasm_out_op(s, OPC_I64_EQZ);
-- 
2.43.0