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-rw-r--r--README.md2
-rw-r--r--wai.c346
2 files changed, 236 insertions, 112 deletions
diff --git a/README.md b/README.md
index 919eda0..df57647 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ Dependencies: wat2wasm from [wabt](https://github.com/WebAssembly/wabt/tree/main
```sh
make
make tests
-./wai tests/factorial.wasw
+./wai tests/factorial.wasm fac 4
```
## Resources
diff --git a/wai.c b/wai.c
index 48f897f..06235c2 100644
--- a/wai.c
+++ b/wai.c
@@ -5,7 +5,7 @@
*
* This program, named WAI, is a WebAssembly Interpreter.
* Compile using make.
- * Usage: wai [FILE.wasm]
+ * Usage: wai [file.wasm] [function name] [function arguments ...]
*
* Copyright (C) 2025 orangrot <me@orangerot.dev>
*
@@ -25,11 +25,17 @@
#include <endian.h>
#include <stddef.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
-#include <inttypes.h>
+
+#define STACK_CAPACITY 1024
+#define MAX_FUNCTIONS 128
+#define MAX_FUNCTION_PARAMETERS 32
+#define MAX_FUNCTION_RESULTS 32
+#define MAX_EXPORT_NAME_LENGTH 128
enum section {
Section_Custom,
@@ -47,13 +53,34 @@ enum section {
Section_Data_Count,
};
-#define STACK_CAPACITY 1024
+enum TYPE {
+ TYPE_I32 = 0x7F,
+ TYPE_I64 = 0x7E,
+ TYPE_F32 = 0x7D,
+ TYPE_F64 = 0x7C,
+ TYPE_V128 = 0x7B,
+ TYPE_FUNCREF = 0x70,
+ TYPE_EXTERNREF = 0x6F
+};
+
struct stack {
u_char items[STACK_CAPACITY];
size_t bytes;
};
-#define MAX_FUNCTIONS 128
+struct func_type_t {
+ enum TYPE param[MAX_FUNCTION_PARAMETERS];
+ enum TYPE result[MAX_FUNCTION_RESULTS];
+ size_t num_params;
+ size_t num_results;
+};
+
+struct func_t {
+ size_t func_type_index;
+ size_t num_local_vars;
+ u_char *func_start_addr;
+};
+
enum export_desc {
Export_Func,
Export_Table,
@@ -62,15 +89,16 @@ enum export_desc {
};
struct export_t {
- u_char name[128];
+ char name[MAX_EXPORT_NAME_LENGTH];
size_t name_length;
- uint32_t index;
+ size_t func_index;
enum export_desc description;
};
struct module {
- struct type_t *types;
- u_char *funcs[MAX_FUNCTIONS];
+ struct func_type_t func_types[MAX_FUNCTIONS]; // TYPE SECTION
+ u_char *code[MAX_FUNCTIONS]; // CODE SECTION
+ size_t func_to_func_type[MAX_FUNCTIONS]; // FUNCTION SECTION
struct table_t *tables;
struct mem_t *mems;
struct global_t *globals;
@@ -81,6 +109,7 @@ struct module {
struct export_t exports[MAX_FUNCTIONS];
u_char *binary;
struct stack stack;
+ size_t num_exports;
int scope;
};
@@ -96,16 +125,6 @@ enum INSTRUCTION {
INSTR_LOCAL_GET = 0x20,
};
-enum TYPE {
- TYPE_I32 = 0x7F,
- TYPE_I64 = 0x7E,
- TYPE_F32 = 0x7D,
- TYPE_F64 = 0x7C,
- TYPE_V128= 0x7B,
- TYPE_FUNCREF = 0x70,
- TYPE_EXTERNREF = 0x6F
-};
-
static const int TYPE_SIZE[] = {
[TYPE_I32] = 4,
[TYPE_I64] = 8,
@@ -116,6 +135,16 @@ static const int TYPE_SIZE[] = {
[TYPE_EXTERNREF] = 16
};
+static const char *TYPE_NAME[] = {
+ [TYPE_I32] = "I32",
+ [TYPE_I64] = "I64",
+ [TYPE_F32] = "F32",
+ [TYPE_F64] = "F64",
+ [TYPE_V128] = "V128",
+ [TYPE_FUNCREF] = "FREF",
+ [TYPE_EXTERNREF] = "EXTR"
+};
+
struct value_t {
enum TYPE type;
union {
@@ -131,6 +160,43 @@ struct value_t {
#define incr(i, len) i++; if (i >= len) {return -1;}
+void print_value(struct value_t *value) {
+ void *number = &value->value;
+ switch (value->type) {
+ case TYPE_I32:
+ printf("%d", *(int32_t*)number);
+ break;
+ case TYPE_I64:
+ printf("%ld", *(int64_t*)number);
+ break;
+ case TYPE_F32:
+ printf("%f", *(float*)number);
+ break;
+ case TYPE_F64:
+ printf("%f", *(double*)number);
+ break;
+ case TYPE_V128:
+ printf("%ld", *(__int128*)number);
+ break;
+ case TYPE_FUNCREF:
+ printf("%ld", *(int64_t*)number);
+ break;
+ case TYPE_EXTERNREF:
+ printf("%ld", *(int64_t*)number);
+ break;
+ }
+ printf(" (%s)", TYPE_NAME[value->type]);
+}
+
+void stack_peak(struct stack *s, struct value_t *value, size_t nth, size_t from) {
+ int byte_i = from - 1;
+ for (int element_i = 0; element_i < nth && byte_i > 0; element_i++) {
+ byte_i -= TYPE_SIZE[s->items[byte_i]];
+ }
+ value->type = s->items[byte_i];
+ memcpy(&value->value, &(s->items[byte_i - TYPE_SIZE[value->type]]), TYPE_SIZE[value->type]);
+}
+
void stack_push(struct stack *s, const struct value_t *value) {
size_t type_size = TYPE_SIZE[value->type];
memcpy(&(s->items[s->bytes]), &value->value, type_size);
@@ -141,31 +207,10 @@ void stack_push(struct stack *s, const struct value_t *value) {
for (int i = s->bytes - 1; i > 0; i -= TYPE_SIZE[s->items[i]] + 1) {
enum TYPE t = s->items[i];
size_t type_size = TYPE_SIZE[t];
- void *value = &s->items[i - type_size];
-
- switch (t) {
- case TYPE_I32:
- printf("%d (I32)", *(int32_t*)value);
- break;
- case TYPE_I64:
- printf("%ld (I32)", *(int64_t*)value);
- break;
- case TYPE_F32:
- printf("%f (F32)", *(float*)value);
- break;
- case TYPE_F64:
- printf("%f (F64)", *(double*)value);
- break;
- case TYPE_V128:
- printf("%ld (V128)", *(__int128*)value);
- break;
- case TYPE_FUNCREF:
- printf("%ld (EREF)", *(int64_t*)value);
- break;
- case TYPE_EXTERNREF:
- printf("%ld (EREF)", *(int64_t*)value);
- break;
- }
+ void *number = &s->items[i - type_size];
+ struct value_t stack_value = {0};
+ stack_peak(s, &stack_value, 0, i + 1);
+ print_value(&stack_value);
printf(", ");
}
printf("\n");
@@ -181,30 +226,10 @@ void stack_pop(struct stack *s, struct value_t *value) {
s->bytes -= TYPE_SIZE[value->type] + 1;
}
-int parse_type(u_char *binary, int len) {
+int parse_function(struct module *module, size_t func_i, int len);
+int parse_instruction(struct module *module, u_char *binary, size_t func_i, size_t func_stack_begin, int len) {
int i = 0;
- enum TYPE param = binary[i];
- printf("type %x\n", param);
- incr(i, len);
- switch (param) {
- case TYPE_I32:
- case TYPE_I64:
- case TYPE_F32:
- case TYPE_F64:
- case TYPE_V128:
- case TYPE_FUNCREF:
- case TYPE_EXTERNREF:
- break;
- default:
- return -1;
- }
- return i;
-}
-
-int parse_function(struct module *module, u_char *binary, double param, int len);
-int parse_instruction(struct module *module, u_char *binary, double param, int len) {
- int i = 0;
- enum INSTRUCTION instr = (u_char) binary[i];
+ enum INSTRUCTION instr = binary[i];
u_char *instr_addr = &binary[i];
struct value_t a = {0};
struct value_t b = {0};
@@ -216,8 +241,8 @@ int parse_instruction(struct module *module, u_char *binary, double param, int l
case INSTR_CALL: {
int func_index = binary[i];
incr(i, len);
- stack_pop(&module->stack, &a);
- parse_function(module, module->funcs[func_index], a.value.f64, len);
+ // stack_pop(&module->stack, &a);
+ parse_function(module, func_index, len);
break;
}
case INSTR_ELSE:
@@ -271,7 +296,7 @@ int parse_instruction(struct module *module, u_char *binary, double param, int l
// TODO test condition with correct type.
// This might not matter since all types are false with 0x0
if (a.value.i64) {
- i += parse_instruction(module, &binary[i], param, len);
+ i += parse_instruction(module, &binary[i], func_i, func_stack_begin, len);
} else {
incr(i, len);
}
@@ -281,7 +306,7 @@ int parse_instruction(struct module *module, u_char *binary, double param, int l
if (a.value.i64) {
incr(i, len);
} else {
- i += parse_instruction(module, &binary[i], param, len);
+ i += parse_instruction(module, &binary[i], func_i, func_stack_begin, len);
}
}
incr(i, len);
@@ -289,8 +314,14 @@ int parse_instruction(struct module *module, u_char *binary, double param, int l
}
case INSTR_LOCAL_GET: {
int local_index = binary[i];
- incr(i, len);
- stack_push(&module->stack, &(struct value_t) {.value.f64 = param, .type = TYPE_F64});
+ size_t func_type_i = module->func_to_func_type[func_i];
+ struct func_type_t *func_type = &module->func_types[func_type_i];
+ // TODO: take local variables into account in addition to parameters
+ int num_locals = func_type->num_params;
+ printf("num locals %d, %d\n", num_locals, num_locals - 1 - local_index);
+ stack_peak(&module->stack, &result, num_locals - 1 - local_index, func_stack_begin);
+ incr(i, len);
+ stack_push(&module->stack, &result);
break;
}
default:
@@ -300,17 +331,34 @@ int parse_instruction(struct module *module, u_char *binary, double param, int l
return i;
}
-int parse_function(struct module *module, u_char *binary, double param, int len) {
+int parse_function(struct module *module, size_t func_i, int len) {
int i = 0;
+ u_char *binary = module->code[func_i];
+ size_t func_type_i = module->func_to_func_type[func_i];
+ struct func_type_t *func_type = &module->func_types[func_type_i];
int body_size = binary[i];
+ size_t func_stack_begin = module->stack.bytes;
+ size_t func_stack_end;
+ struct value_t result = {0};
+
incr(i, len);
// int local_decl_cound = binary[i];
incr(i, len);
module->scope = 1;
while (binary[i] != INSTR_END) {
- i += parse_instruction(module, &binary[i], param, len);
+ i += parse_instruction(module, &binary[i], func_i, func_stack_begin, len);
}
incr(i, len);
+
+ func_stack_end = module->stack.bytes;
+ module->stack.bytes = func_stack_begin;
+ for (size_t param_i = 0; param_i < func_type->num_params; param_i++) {
+ stack_pop(&module->stack, &result);
+ }
+ for (size_t result_i = 0; result_i < func_type->num_results; result_i++) {
+ stack_peak(&module->stack, &result, func_type->num_results - 1 - result_i, func_stack_end);
+ stack_push(&module->stack, &result);
+ }
return i;
}
@@ -327,23 +375,27 @@ int parse_section(struct module *module, u_char *binary, int len) {
break;
case Section_Type:
printf("section: type\n");
- int num_types = binary[i];
+ struct func_type_t *func_type;
+ size_t num_types = binary[i];
incr(i, len);
- for (int type_i = 0; type_i < num_types; type_i++) {
+ for (size_t type_i = 0; type_i < num_types; type_i++) {
if (binary[i] != 0x60) {
printf("expected function type, found %x\n", binary[i]);
return -1;
}
incr(i, len);
- int num_params = binary[i];
+ func_type = &module->func_types[type_i];
+ func_type->num_params = binary[i];
incr(i, len);
- for (int params_i = 0; params_i < num_params; params_i++) {
- i += (parse_type(&binary[i], len));
+ for (size_t param_i = 0; param_i < func_type->num_params; param_i++) {
+ func_type->param[param_i] = binary[i];
+ incr(i, len);
}
- int num_results = binary[i];
+ func_type->num_results = binary[i];
incr(i, len);
- for (int results_i = 0; results_i < num_results; results_i++) {
- i += (parse_type(&binary[i], len));
+ for (size_t result_i = 0; result_i < func_type->num_results; result_i++) {
+ func_type->result[result_i] = binary[i];
+ incr(i, len);
}
}
break;
@@ -351,9 +403,10 @@ int parse_section(struct module *module, u_char *binary, int len) {
break;
case Section_Function:
printf("section: function\n");
- int num_functions = binary[i];
+ size_t num_functions = binary[i];
incr(i, len);
- for (int function_i = 0; function_i < num_functions; function_i++) {
+ for (size_t function_i = 0; function_i < num_functions; function_i++) {
+ module->func_to_func_type[function_i] = binary[i];
incr(i, len);
}
break;
@@ -365,28 +418,48 @@ int parse_section(struct module *module, u_char *binary, int len) {
break;
case Section_Export:
printf("section: exports\n");
- int num_exports = binary[i];
+ module->num_exports = binary[i];
- if(num_exports > MAX_FUNCTIONS) {
- printf("Number of exports exceeds maximum number of functions in a module (%d)", MAX_FUNCTIONS);
- return -1;
+ if(module->num_exports > MAX_FUNCTIONS) {
+ printf("Number of exports exceeds maximum number of functions in a module (%d)", MAX_FUNCTIONS);
+ return -1;
}
incr(i, len);
- for (int exports_i = 0; exports_i < num_exports; exports_i++) {
- struct export_t *export = &module->exports[i];
+ for (size_t exports_i = 0; exports_i < module->num_exports; exports_i++) {
+ struct export_t *export = &module->exports[exports_i];
export->name_length = binary[i];
incr(i, len);
-
- for (int si = 0; si < export->name_length; si++) {
- export->name[si] = binary[i];
+
+ for (size_t si = 0; si < export->name_length; si++) {
+ export->name[si] = (char) binary[i];
incr(i, len);
}
- export->description = (int) binary[i];
+ export->description = (enum export_desc) binary[i];
incr(i, len);
- export->index = (uint32_t) binary[i];
- printf("export name: %s of type %d\n", export->name, export->description);
+ export->func_index = (size_t) binary[i];
+ printf("export name: %s of type %d\n", export->name, export->description);
+ if (export->description == Export_Func) {
+ printf("exported function %s(", export->name);
+ size_t func_type_index = module->func_to_func_type[export->func_index];
+ struct func_type_t *func_type = &module->func_types[func_type_index];
+ for (size_t param_i = 0; param_i < func_type->num_params; param_i++) {
+ printf("%s", TYPE_NAME[func_type->param[param_i]]);
+ if (param_i == func_type->num_params -1) {
+ printf(") -> ");
+ } else {
+ printf(",");
+ }
+ }
+ for (size_t result_i = 0; result_i < func_type->num_results; result_i++) {
+ printf("%s", TYPE_NAME[func_type->result[result_i]]);
+ if (result_i != func_type->num_params -1) {
+ printf(",");
+ }
+ }
+ printf("\n");
+ }
incr(i, len);
}
break;
@@ -399,8 +472,10 @@ int parse_section(struct module *module, u_char *binary, int len) {
int num_functions2 = binary[i];
incr(i, len);
for (int function_i = 0; function_i < num_functions2; function_i++) {
- module->funcs[function_i] = &binary[i];
- i += parse_function(module, &binary[i], 4, len);
+ module->code[function_i] = &binary[i];
+ stack_push(&module->stack, &(struct value_t) {.type = TYPE_F64, .value.f64 = 1});
+ i += parse_function(module, function_i, len);
+ stack_pop(&module->stack, &(struct value_t) {0});
}
// printf("result: %f\n", module->stack.items[0]);
break;
@@ -417,7 +492,7 @@ int parse_section(struct module *module, u_char *binary, int len) {
return i;
}
-int parse_module(u_char *binary, size_t len) {
+int parse_module(struct module *module, u_char *binary, size_t len) {
int i = 0;
char *magic = "\0asm";
while (i < 4) {
@@ -432,40 +507,89 @@ int parse_module(u_char *binary, size_t len) {
i += 4;
printf("addr %d\n", i);
- struct module module = {0};
- module.binary = binary;
+ module->binary = binary;
while (i < len) {
- i += parse_section(&module, &binary[i], len);
+ i += parse_section(module, &binary[i], len);
}
return i;
}
int main(int argc, char **argv) {
-
+ FILE *file;
+ u_char *binary;
+ struct stat st;
+ struct module module = {0};
+
if (argc != 2) {
- fprintf(stderr, "Usage: %s [file]\n", argv[0]);
- return 1;
+ printf("Usage: %s [file] [function name] [function arguments ...]\n", argv[0]);
};
- FILE *file = fopen(argv[1], "r");
+ file = fopen(argv[1], "r");
if (file == NULL) {
fprintf(stderr, "Failed to open file\n");
fclose(file);
return 1;
}
- struct stat st;
stat(argv[1], &st);
printf("size: %ld\n", st.st_size);
- u_char *binary = malloc(st.st_size);
+ binary = malloc(st.st_size);
fread(binary, st.st_size, 1, file);
+ fclose(file);
- if (parse_module(binary, st.st_size) == -1) {
+ if (parse_module(&module, binary, st.st_size) == -1) {
printf("error :(\n");
}
-
+ printf("%zu\n", module.num_exports);
+ printf("%s\n", module.exports[0].name);
+ size_t export_search_i = 0;
+ while (export_search_i < module.num_exports &&
+ (strcmp(module.exports[export_search_i].name, argv[2]) != 0)) {
+ export_search_i++;
+ }
+ if (export_search_i == module.num_exports) {
+ printf("Provided function name %s not recognised. \n", argv[2]);
+ exit(1);
+ }
+ size_t function_search_i = module.exports[export_search_i].func_index;
+ struct func_type_t *func_type_search = &module.func_types[module.func_to_func_type[function_search_i]];
+ if (func_type_search->num_params != argc - 3) {
+ printf("Not enough function arguments provided. Got %d expected %zu. \n", argc - 3, func_type_search->num_params);
+ exit(1);
+ }
+
+ for (size_t param_i = 0; param_i < func_type_search->num_params; param_i++) {
+ enum TYPE param_type = func_type_search->param[param_i];
+ struct value_t param = {
+ .type = param_type,
+ .value = {0}
+ };
+ char *param_str = argv[param_i + 3];
+ switch (param_type) {
+ case TYPE_I32:
+ param.value.i32 = atoi(param_str);
+ break;
+ case TYPE_I64:
+ param.value.i64 = atoll(param_str);
+ break;
+ case TYPE_F32:
+ param.value.f32 = strtof(param_str, NULL);
+ break;
+ case TYPE_F64:
+ param.value.f64 = strtod(param_str, NULL);
+ break;
+ case TYPE_V128:
+ case TYPE_FUNCREF:
+ case TYPE_EXTERNREF:
+ default:
+ printf("%s, %s, %s unsupported\n", TYPE_NAME[TYPE_V128], TYPE_NAME[TYPE_FUNCREF], TYPE_NAME[TYPE_EXTERNREF]);
+ exit(1);
+ }
+ stack_push(&module.stack, &param);
+ }
+ parse_function(&module, function_search_i, 100);
+
free(binary);
- fclose(file);
return 0;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-03 21:23:16 +0000