phasm/stdlib/alloc.py

@@ -0,0 +1,129 @@
+"""
+stdlib: Memory allocation
+"""
+from phasm.wasmeasy import Generator, func_wrapper
+
+IDENTIFIER = 0xA1C0
+
+ADR_IDENTIFIER = 0
+ADR_RESERVED0 = ADR_IDENTIFIER + 4
+ADR_FREE_BLOCK_PTR = ADR_RESERVED0 + 4
+ADR_UNALLOC_PTR = ADR_FREE_BLOCK_PTR + 4
+
+@func_wrapper
+def __init__(g: Generator) -> None:
+    """
+    Initializes the memory so we can allocate it
+    """
+
+    # Check if the memory is already initialized
+    g.i32.const(0)
+    g.i32.load()
+    g.i32.const(IDENTIFIER)
+    g.i32.eq()
+
+    with g.if_():
+        # Already initialized, return without any changes
+        g.return_()
+
+    # Store the first reserved i32
+    g.i32.const(ADR_RESERVED0)
+    g.i32.const(0)
+    g.i32.store()
+
+    # Store the pointer towards the first free block
+    # In this case, 0 since we haven't freed any blocks yet
+    g.i32.const(ADR_FREE_BLOCK_PTR)
+    g.i32.const(0)
+    g.i32.store()
+
+    # Store the pointer towards the first unallocated block
+    # In this case the end of the stdlib.alloc header at the start
+    g.i32.const(ADR_UNALLOC_PTR)
+    g.i32.const(0x10)
+    g.i32.store()
+
+    # Store that we've initialized the memory
+    g.i32.const(0)
+    g.i32.const(IDENTIFIER)
+    g.i32.store()
+
+
+@func_wrapper
+def __find_free_block__(g: Generator) -> None:
+    # Find out if we've freed any blocks at all so far
+    g.i32.const(ADR_FREE_BLOCK_PTR)
+    g.i32.load()
+    g.i32.const(0)
+    g.i32.eq()
+
+    with g.if_():
+        g.i32.const(0)
+        g.return_()
+
+    g.unreachable()
+
+@func_wrapper
+def __alloc__(g: Generator) -> None:
+    g.i32.const(ADR_IDENTIFIER)
+    g.i32.load()
+    g.i32.const(IDENTIFIER)
+    g.i32.ne()
+    with g.if_():
+        g.unreachable()
+
+# def _generate_stdlib_alloc___alloc__(mod: ourlang.Module) -> wasm.Function:
+#     return wasm.Function(
+#         'stdlib.alloc.__alloc__',
+#         'stdlib.alloc.__alloc__',
+#         [
+#             ('alloc_size', type_(mod.types['i32']), ),
+#         ],
+#         [
+#             ('result', type_(mod.types['i32']), ),
+#         ],
+#         type_(mod.types['i32']),
+#         [
+#             i32.const(0),
+#             i32.load(),
+#             i32.const(STDLIB_ALLOC__IDENTIFIER),
+#             i32.ne(),
+#             *wasmeasy.if_(
+#                 wasm.Statement('unreachable'),
+#             ),
+#
+#             wasm.Statement('local.get', '$alloc_size'),
+#             wasm.Statement('call', '$stdlib.alloc.__find_free_block__'),
+#             wasm.Statement('local.set', '$result'),
+#
+#             # Check if there was a free block
+#             wasm.Statement('local.get', '$result'),
+#             i32.const(0),
+#             i32.eq(),
+#             *wasmeasy.if_(
+#                 # Use unallocated space
+#                 i32.const(STDLIB_ALLOC__ADR_UNALLOC_PTR),
+#
+#                 i32.const(STDLIB_ALLOC__ADR_UNALLOC_PTR),
+#                 i32.load(),
+#                 wasm.Statement('local.tee', '$result'),
+#
+#                 # Updated unalloc pointer (address already set on stack)
+#                 i32.const(4), # Header size
+#                 i32.add(),
+#                 wasm.Statement('local.get', '$alloc_size'),
+#                 i32.add(),
+#                 i32.store('offset=0'),
+#             ),
+#
+#             # Store block size
+#             wasm.Statement('local.get', '$result'),
+#             wasm.Statement('local.get', '$alloc_size'),
+#             i32.store('offset=0'),
+#
+#             # Return address of the allocated bytes
+#             wasm.Statement('local.get', '$result'),
+#             i32.const(4), # Header size
+#             i32.add(),
+#         ],
+#     )

phasm/wasmeasy.py

@@ -1,7 +1,7 @@
 """
 Helper functions to quickly generate WASM code
 """
-from typing import List, Optional
+from typing import Any, List, Optional
 
 import functools
 
@@ -67,3 +67,76 @@ class Block:
         ]
 
 if_ = Block('if')
+
+class Generator_i32:
+    def __init__(self, generator: 'Generator') -> None:
+        self.generator = generator
+
+        # 2.4.1. Numeric Instructions
+        self.eq = functools.partial(self.generator.add, 'i32.eq')
+        self.ne = functools.partial(self.generator.add, 'i32.ne')
+
+        # 2.4.4. Memory Instructions
+        self.load = functools.partial(self.generator.add, 'i32.load')
+        self.store = functools.partial(self.generator.add, 'i32.store')
+
+    def const(self, value: int, comment: Optional[str] = None) -> None:
+        self.generator.add('i32.const', f'0x{value:08x}', comment=comment)
+
+class GeneratorBlock:
+    def __init__(self, generator: 'Generator', name: str) -> None:
+        self.generator = generator
+        self.name = name
+
+    def __enter__(self) -> None:
+        self.generator.add(self.name)
+
+    def __exit__(self, exc_type: Any, exc_value: Any, traceback: Any) -> None:
+        if not exc_type:
+            self.generator.add('end')
+
+class Generator:
+    def __init__(self) -> None:
+        self.statements: List[wasm.Statement] = []
+
+        self.i32 = Generator_i32(self)
+
+        # 2.4.5 Control Instructions
+        self.nop = functools.partial(self.add, 'nop')
+        self.unreachable = functools.partial(self.add, 'unreachable')
+        # block
+        # loop
+        self.if_ = functools.partial(GeneratorBlock, self, 'if')
+        # br
+        # br_if
+        # br_table
+        self.return_ = functools.partial(self.add, 'return')
+        # call
+        # call_indirect
+
+    def add(self, name: str, *args: str, comment: Optional[str] = None) -> None:
+        self.statements.append(wasm.Statement(name, *args, comment=comment))
+
+def func_wrapper(func: Any) -> wasm.Function:
+    assert func.__module__.startswith('phasm.')
+
+    assert Generator is func.__annotations__['g']
+
+    params: Any = []
+
+    locals_: Any = []
+
+    assert None is func.__annotations__['return']
+    return_type = wasm.WasmTypeNone()
+
+    generator = Generator()
+    func(g=generator)
+
+    return wasm.Function(
+        func.__module__[6:] + '.' + func.__name__,
+        func.__module__[6:] + '.' + func.__name__,
+        params,
+        locals_,
+        return_type,
+        generator.statements,
+    )

pylintrc

@@ -1,2 +1,5 @@
 [MASTER]
 disable=C0122,R0903,R0911,R0912,R0913,R0915,R1710,W0223
+
+[stdlib]
+good-names=g