wasm2c: implement the tail-call proposal

WebAssembly · Jul 30, 2023 · e677efa · e677efa
1 parent 91548be
commit e677efa
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Showing 17 changed files with 849 additions and 80 deletions.
diff --git a/src/c-writer.cc b/src/c-writer.cc
diff --git a/src/prebuilt/wasm2c_source_declarations.cc b/src/prebuilt/wasm2c_source_declarations.cc
@@ -46,6 +46,19 @@ R"w2c_template(       TRAP(CALL_INDIRECT),                              \
 R"w2c_template(   ((t)table.data[x].func)(__VA_ARGS__))
 )w2c_template"
 R"w2c_template(
+#define RETURN_CALL_INDIRECT(table, ft, x)                        \
+)w2c_template"
+R"w2c_template(  (LIKELY((x) < table.size && table.data[x].func_tailcallee.fn && \
+)w2c_template"
+R"w2c_template(          func_types_eq(ft, table.data[x].func_type)) ||          \
+)w2c_template"
+R"w2c_template(       TRAP(CALL_INDIRECT),                                       \
+)w2c_template"
+R"w2c_template(   (next->fn = table.data[x].func_tailcallee.fn,                  \
+)w2c_template"
+R"w2c_template(    *instance_ptr = table.data[x].module_instance))
+)w2c_template"
+R"w2c_template(
 #ifdef SUPPORT_MEMORY64
 )w2c_template"
 R"w2c_template(#define RANGE_CHECK(mem, offset, len)              \
@@ -922,6 +935,8 @@ R"w2c_template(  wasm_rt_func_type_t type;
 )w2c_template"
 R"w2c_template(  wasm_rt_function_ptr_t func;
 )w2c_template"
+R"w2c_template(  wasm_rt_tailcallee_t func_tailcallee;
+)w2c_template"
 R"w2c_template(  size_t module_offset;
 )w2c_template"
 R"w2c_template(} wasm_elem_segment_expr_t;
@@ -953,11 +968,11 @@ R"w2c_template(  for (u32 i = 0; i < n; i++) {
 )w2c_template"
 R"w2c_template(    const wasm_elem_segment_expr_t* src_expr = &src[src_addr + i];
 )w2c_template"
-R"w2c_template(    dest->data[dest_addr + i] =
+R"w2c_template(    dest->data[dest_addr + i] = (wasm_rt_funcref_t){
 )w2c_template"
-R"w2c_template(        (wasm_rt_funcref_t){src_expr->type, src_expr->func,
+R"w2c_template(        src_expr->type, src_expr->func, src_expr->func_tailcallee,
 )w2c_template"
-R"w2c_template(                            (char*)module_instance + src_expr->module_offset};
+R"w2c_template(        (char*)module_instance + src_expr->module_offset};
 )w2c_template"
 R"w2c_template(  }
 )w2c_template"
@@ -1107,4 +1122,15 @@ R"w2c_template(#define FUNC_TYPE_T(x) static const char x[]
 )w2c_template"
 R"w2c_template(#endif
 )w2c_template"
+R"w2c_template(
+#if (__STDC_VERSION__ >= 201112L) || defined(_Static_assert)
+)w2c_template"
+R"w2c_template(#define wasm_static_assert(X) _Static_assert(X, "assertion failure")
+)w2c_template"
+R"w2c_template(#else
+)w2c_template"
+R"w2c_template(#define wasm_static_assert assert
+)w2c_template"
+R"w2c_template(#endif
+)w2c_template"
 ;
diff --git a/src/template/wasm2c.declarations.c b/src/template/wasm2c.declarations.c
@@ -26,6 +26,13 @@ static inline bool func_types_eq(const wasm_rt_func_type_t a,
        TRAP(CALL_INDIRECT),                              \
    ((t)table.data[x].func)(__VA_ARGS__))
 
+#define RETURN_CALL_INDIRECT(table, ft, x)                        \
+  (LIKELY((x) < table.size && table.data[x].func_tailcallee.fn && \
+          func_types_eq(ft, table.data[x].func_type)) ||          \
+       TRAP(CALL_INDIRECT),                                       \
+   (next->fn = table.data[x].func_tailcallee.fn,                  \
+    *instance_ptr = table.data[x].module_instance))
+
 #ifdef SUPPORT_MEMORY64
 #define RANGE_CHECK(mem, offset, len)              \
   do {                                             \
@@ -493,6 +500,7 @@ static inline void memory_init(wasm_rt_memory_t* dest,
 typedef struct {
   wasm_rt_func_type_t type;
   wasm_rt_function_ptr_t func;
+  wasm_rt_tailcallee_t func_tailcallee;
   size_t module_offset;
 } wasm_elem_segment_expr_t;
 
@@ -509,9 +517,9 @@ static inline void funcref_table_init(wasm_rt_funcref_table_t* dest,
     TRAP(OOB);
   for (u32 i = 0; i < n; i++) {
     const wasm_elem_segment_expr_t* src_expr = &src[src_addr + i];
-    dest->data[dest_addr + i] =
-        (wasm_rt_funcref_t){src_expr->type, src_expr->func,
-                            (char*)module_instance + src_expr->module_offset};
+    dest->data[dest_addr + i] = (wasm_rt_funcref_t){
+        src_expr->type, src_expr->func, src_expr->func_tailcallee,
+        (char*)module_instance + src_expr->module_offset};
   }
 }
 
@@ -591,3 +599,9 @@ DEFINE_TABLE_FILL(externref)
 #define FUNC_TYPE_EXTERN_T(x) const char x[]
 #define FUNC_TYPE_T(x) static const char x[]
 #endif
+
+#if (__STDC_VERSION__ >= 201112L) || defined(_Static_assert)
+#define wasm_static_assert(X) _Static_assert(X, "assertion failure")
+#else
+#define wasm_static_assert assert
+#endif
diff --git a/src/tools/wasm2c.cc b/src/tools/wasm2c.cc
@@ -61,7 +61,7 @@ static const char s_description[] =
 static const std::string supported_features[] = {
     "multi-memory", "multi-value", "sign-extension", "saturating-float-to-int",
     "exceptions",   "memory64",    "extended-const", "simd",
-    "threads"};
+    "threads",      "tail-call"};
 
 static bool IsFeatureSupported(const std::string& feature) {
   return std::find(std::begin(supported_features), std::end(supported_features),

diff --git a/test/run-spec-wasm2c.py b/test/run-spec-wasm2c.py
@@ -533,6 +533,7 @@ def main(args):
     parser.add_argument('--enable-memory64', action='store_true')
     parser.add_argument('--enable-extended-const', action='store_true')
     parser.add_argument('--enable-threads', action='store_true')
+    parser.add_argument('--enable-tail-call', action='store_true')
     parser.add_argument('--disable-bulk-memory', action='store_true')
     parser.add_argument('--disable-reference-types', action='store_true')
     parser.add_argument('--debug-names', action='store_true')
@@ -553,6 +554,7 @@ def main(args):
             '--enable-memory64': options.enable_memory64,
             '--enable-extended-const': options.enable_extended_const,
             '--enable-threads': options.enable_threads,
+            '--enable-tail-call': options.enable_tail_call,
             '--enable-multi-memory': options.enable_multi_memory,
             '--disable-bulk-memory': options.disable_bulk_memory,
             '--disable-reference-types': options.disable_reference_types,
@@ -571,6 +573,7 @@ def main(args):
             '--enable-memory64': options.enable_memory64,
             '--enable-extended-const': options.enable_extended_const,
             '--enable-threads': options.enable_threads,
+            '--enable-tail-call': options.enable_tail_call,
             '--enable-multi-memory': options.enable_multi_memory})
 
         options.cflags += shlex.split(os.environ.get('WASM2C_CFLAGS', ''))

diff --git a/test/wasm2c/add.txt b/test/wasm2c/add.txt
@@ -41,6 +41,9 @@ wasm_rt_func_type_t wasm2c_test_get_func_type(uint32_t param_count, uint32_t res
 /* export: 'add' */
 u32 w2c_test_add(w2c_test*, u32, u32);
 
+/* export for tail-call of 'add' */
+void wasm2c_tailcall_1024_w2c_test_add(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next);
+
 #ifdef __cplusplus
 }
 #endif
@@ -93,6 +96,13 @@ static inline bool func_types_eq(const wasm_rt_func_type_t a,
        TRAP(CALL_INDIRECT),                              \
    ((t)table.data[x].func)(__VA_ARGS__))
 
+#define RETURN_CALL_INDIRECT(table, ft, x)                        \
+  (LIKELY((x) < table.size && table.data[x].func_tailcallee.fn && \
+          func_types_eq(ft, table.data[x].func_type)) ||          \
+       TRAP(CALL_INDIRECT),                                       \
+   (next->fn = table.data[x].func_tailcallee.fn,                  \
+    *instance_ptr = table.data[x].module_instance))
+
 #ifdef SUPPORT_MEMORY64
 #define RANGE_CHECK(mem, offset, len)              \
   do {                                             \
@@ -560,6 +570,7 @@ static inline void memory_init(wasm_rt_memory_t* dest,
 typedef struct {
   wasm_rt_func_type_t type;
   wasm_rt_function_ptr_t func;
+  wasm_rt_tailcallee_t func_tailcallee;
   size_t module_offset;
 } wasm_elem_segment_expr_t;
 
@@ -576,9 +587,9 @@ static inline void funcref_table_init(wasm_rt_funcref_table_t* dest,
     TRAP(OOB);
   for (u32 i = 0; i < n; i++) {
     const wasm_elem_segment_expr_t* src_expr = &src[src_addr + i];
-    dest->data[dest_addr + i] =
-        (wasm_rt_funcref_t){src_expr->type, src_expr->func,
-                            (char*)module_instance + src_expr->module_offset};
+    dest->data[dest_addr + i] = (wasm_rt_funcref_t){
+        src_expr->type, src_expr->func, src_expr->func_tailcallee,
+        (char*)module_instance + src_expr->module_offset};
   }
 }
 
@@ -659,7 +670,22 @@ DEFINE_TABLE_FILL(externref)
 #define FUNC_TYPE_T(x) static const char x[]
 #endif
 
+#if (__STDC_VERSION__ >= 201112L) || defined(_Static_assert)
+#define wasm_static_assert(X) _Static_assert(X, "assertion failure")
+#else
+#define wasm_static_assert assert
+#endif
+
 static u32 w2c_test_add_0(w2c_test*, u32, u32);
+static void wasm2c_tailcall_1024_w2c_test_add_0(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next);
+
+#ifndef wasm_multi_ii
+#define wasm_multi_ii wasm_multi_ii
+struct wasm_multi_ii {
+  u32 i0;
+  u32 i1;
+};
+#endif  /* wasm_multi_ii */
 
 FUNC_TYPE_T(w2c_test_t0) = "\x92\xfb\x6a\xdf\x49\x07\x0a\x83\xbe\x08\x02\x68\xcd\xf6\x95\x27\x4a\xc2\xf3\xe5\xe4\x7d\x29\x49\xe8\xed\x42\x92\x6a\x9d\xda\xf0";
 
@@ -668,6 +694,11 @@ u32 w2c_test_add(w2c_test* instance, u32 var_p0, u32 var_p1) {
   return w2c_test_add_0(instance, var_p0, var_p1);
 }
 
+/* export for tail-call of 'add' */
+void wasm2c_tailcall_1024_w2c_test_add(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next) {
+  wasm2c_tailcall_1024_w2c_test_add_0(instance_ptr, tail_call_stack, next);
+}
+
 void wasm2c_test_instantiate(w2c_test* instance) {
   assert(wasm_rt_is_initialized());
 }
@@ -699,4 +730,22 @@ u32 w2c_test_add_0(w2c_test* instance, u32 var_p0, u32 var_p1) {
   FUNC_EPILOGUE;
   return var_i0;
 }
+
+void wasm2c_tailcall_1024_w2c_test_add_0(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next) {
+  wasm_static_assert(sizeof(struct wasm_multi_ii) <= 1024);
+  wasm_static_assert(sizeof(u32) <= 1024);
+  w2c_test* instance = *instance_ptr;
+  u32 var_p0, var_p1;
+  {
+    struct wasm_multi_ii *tmp = tail_call_stack;
+    var_p0 = tmp->i0;
+    var_p1 = tmp->i1;
+  }
+  u32 var_i0, var_i1;
+  var_i0 = var_p0;
+  var_i1 = var_p1;
+  var_i0 += var_i1;
+  wasm_rt_memcpy(tail_call_stack, &var_i0, sizeof(var_i0));
+  next->fn = NULL;
+}
 ;;; STDOUT ;;)
diff --git a/test/wasm2c/check-imports.txt b/test/wasm2c/check-imports.txt
@@ -116,6 +116,13 @@ static inline bool func_types_eq(const wasm_rt_func_type_t a,
        TRAP(CALL_INDIRECT),                              \
    ((t)table.data[x].func)(__VA_ARGS__))
 
+#define RETURN_CALL_INDIRECT(table, ft, x)                        \
+  (LIKELY((x) < table.size && table.data[x].func_tailcallee.fn && \
+          func_types_eq(ft, table.data[x].func_type)) ||          \
+       TRAP(CALL_INDIRECT),                                       \
+   (next->fn = table.data[x].func_tailcallee.fn,                  \
+    *instance_ptr = table.data[x].module_instance))
+
 #ifdef SUPPORT_MEMORY64
 #define RANGE_CHECK(mem, offset, len)              \
   do {                                             \
@@ -583,6 +590,7 @@ static inline void memory_init(wasm_rt_memory_t* dest,
 typedef struct {
   wasm_rt_func_type_t type;
   wasm_rt_function_ptr_t func;
+  wasm_rt_tailcallee_t func_tailcallee;
   size_t module_offset;
 } wasm_elem_segment_expr_t;
 
@@ -599,9 +607,9 @@ static inline void funcref_table_init(wasm_rt_funcref_table_t* dest,
     TRAP(OOB);
   for (u32 i = 0; i < n; i++) {
     const wasm_elem_segment_expr_t* src_expr = &src[src_addr + i];
-    dest->data[dest_addr + i] =
-        (wasm_rt_funcref_t){src_expr->type, src_expr->func,
-                            (char*)module_instance + src_expr->module_offset};
+    dest->data[dest_addr + i] = (wasm_rt_funcref_t){
+        src_expr->type, src_expr->func, src_expr->func_tailcallee,
+        (char*)module_instance + src_expr->module_offset};
   }
 }
 
@@ -682,9 +690,26 @@ DEFINE_TABLE_FILL(externref)
 #define FUNC_TYPE_T(x) static const char x[]
 #endif
 
+#if (__STDC_VERSION__ >= 201112L) || defined(_Static_assert)
+#define wasm_static_assert(X) _Static_assert(X, "assertion failure")
+#else
+#define wasm_static_assert assert
+#endif
+
 static u32 w2c_test_f0(w2c_test*, u32);
+static void wasm2c_tailcall_1024_w2c_test_f0(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next);
 static u32 w2c_test_f1(w2c_test*);
+static void wasm2c_tailcall_1024_w2c_test_f1(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next);
 static u32 w2c_test_f2(w2c_test*, u32, u32);
+static void wasm2c_tailcall_1024_w2c_test_f2(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next);
+
+#ifndef wasm_multi_ii
+#define wasm_multi_ii wasm_multi_ii
+struct wasm_multi_ii {
+  u32 i0;
+  u32 i1;
+};
+#endif  /* wasm_multi_ii */
 
 FUNC_TYPE_T(w2c_test_t0) = "\x07\x80\x96\x7a\x42\xf7\x3e\xe6\x70\x5c\x2f\xac\x83\xf5\x67\xd2\xa2\xa0\x69\x41\x5f\xf8\xe7\x96\x7f\x23\xab\x00\x03\x5f\x4a\x3c";
 FUNC_TYPE_T(w2c_test_t1) = "\x72\xab\x00\xdf\x20\x3d\xce\xa1\xf2\x29\xc7\x9d\x13\x40\x7e\x98\xac\x7d\x41\x4a\x53\x2e\x42\x42\x61\x55\x2e\xaa\xeb\xbe\xc6\x35";
@@ -694,7 +719,7 @@ static void init_memories(w2c_test* instance) {
 }
 
 static const wasm_elem_segment_expr_t elem_segment_exprs_w2c_test_e0[] = {
-  {w2c_test_t1, (wasm_rt_function_ptr_t)w2c_test_f1, 0},
+  {w2c_test_t1, (wasm_rt_function_ptr_t)w2c_test_f1, {wasm2c_tailcall_1024_w2c_test_f1}, 0},
 };
 
 static void init_tables(w2c_test* instance) {
@@ -768,6 +793,17 @@ u32 w2c_test_f0(w2c_test* instance, u32 var_p0) {
   return var_i0;
 }
 
+void wasm2c_tailcall_1024_w2c_test_f0(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next) {
+  wasm_static_assert(sizeof(u32) <= 1024);
+  w2c_test* instance = *instance_ptr;
+  u32 var_p0 = *(u32*)tail_call_stack;
+  u32 var_i0;
+  var_i0 = var_p0;
+  var_i0 = CALL_INDIRECT((*instance->w2c_env_0x5F_indirect_function_table), u32 (*)(void*), w2c_test_t1, var_i0, (*instance->w2c_env_0x5F_indirect_function_table).data[var_i0].module_instance);
+  wasm_rt_memcpy(tail_call_stack, &var_i0, sizeof(var_i0));
+  next->fn = NULL;
+}
+
 u32 w2c_test_f1(w2c_test* instance) {
   FUNC_PROLOGUE;
   u32 var_i0;
@@ -777,6 +813,16 @@ u32 w2c_test_f1(w2c_test* instance) {
   return var_i0;
 }
 
+void wasm2c_tailcall_1024_w2c_test_f1(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next) {
+  wasm_static_assert(sizeof(u32) <= 1024);
+  w2c_test* instance = *instance_ptr;
+  u32 var_i0;
+  var_i0 = 16u;
+  var_i0 = i32_load(instance->w2c_env_0x5F_linear_memory, (u64)(var_i0));
+  wasm_rt_memcpy(tail_call_stack, &var_i0, sizeof(var_i0));
+  next->fn = NULL;
+}
+
 u32 w2c_test_f2(w2c_test* instance, u32 var_p0, u32 var_p1) {
   FUNC_PROLOGUE;
   u32 var_i0;
@@ -785,4 +831,21 @@ u32 w2c_test_f2(w2c_test* instance, u32 var_p0, u32 var_p1) {
   FUNC_EPILOGUE;
   return var_i0;
 }
+
+void wasm2c_tailcall_1024_w2c_test_f2(void **instance_ptr, void *tail_call_stack, wasm_rt_tailcallee_t *next) {
+  wasm_static_assert(sizeof(struct wasm_multi_ii) <= 1024);
+  wasm_static_assert(sizeof(u32) <= 1024);
+  w2c_test* instance = *instance_ptr;
+  u32 var_p0, var_p1;
+  {
+    struct wasm_multi_ii *tmp = tail_call_stack;
+    var_p0 = tmp->i0;
+    var_p1 = tmp->i1;
+  }
+  u32 var_i0;
+  var_i0 = 1u;
+  var_i0 = w2c_test_f0(instance, var_i0);
+  wasm_rt_memcpy(tail_call_stack, &var_i0, sizeof(var_i0));
+  next->fn = NULL;
+}
 ;;; STDOUT ;;)