[PATCH 26/33] tcg/wasm32: Add initialization of fundamental registers

[Kohei Tokunaga]

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. Since TB execution begins at
the first block, the BLOCK_PTR_IDX variable is initialized to 0.

Signed-off-by: Kohei Tokunaga <ktokunaga.m...@gmail.com>
---
 tcg/wasm32.h                | 10 ++++++++++
 tcg/wasm32/tcg-target.c.inc | 17 +++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/tcg/wasm32.h b/tcg/wasm32.h
index 1944249891..ab23e26eca 100644
--- a/tcg/wasm32.h
+++ b/tcg/wasm32.h
@@ -22,6 +22,16 @@ struct wasmContext {
      * Buffer to store 128bit return value on call.
      */
     void *buf128;
+
+    /*
+     * Pointer to CPUArchState struct.
+     */
+    CPUArchState *env;
+
+    /*
+     * Pointer to a stack array.
+     */
+    uint64_t *stack;
 };
 
 #endif
diff --git a/tcg/wasm32/tcg-target.c.inc b/tcg/wasm32/tcg-target.c.inc
index df34097267..4b7cd784cb 100644
--- a/tcg/wasm32/tcg-target.c.inc
+++ b/tcg/wasm32/tcg-target.c.inc
@@ -3258,6 +3258,23 @@ static void tcg_out_tb_start(TCGContext *s)
     init_label_info();
     init_helpers();
 
+    /* generate wasm code to initialize fundamental registers */
+    tcg_wasm_out_op_global_get_r(s, TCG_AREG0);
+    tcg_wasm_out_op_i64_eqz(s);
+    tcg_wasm_out_op_if_noret(s);
+
+    tcg_wasm_out_ctx_i32_load(s, env);
+    tcg_wasm_out_op_i64_extend_i32_u(s);
+    tcg_wasm_out_op_global_set_r(s, TCG_AREG0);
+
+    tcg_wasm_out_ctx_i32_load(s, stack);
+    tcg_wasm_out_op_i64_extend_i32_u(s);
+    tcg_wasm_out_op_global_set_r(s, TCG_REG_CALL_STACK);
+    tcg_wasm_out_op_end(s);
+
+    tcg_wasm_out_op_i64_const(s, 0);
+    tcg_wasm_out_op_global_set(s, BLOCK_PTR_IDX);
+
     tcg_wasm_out_op_loop_noret(s);
     tcg_wasm_out_op_global_get(s, BLOCK_PTR_IDX);
     tcg_wasm_out_op_i64_eqz(s);
-- 
2.43.0