Preprocessor for ULP/RTC macros

esp32_ulp/assemble.py

@@ -12,9 +12,10 @@
 
 
 class SymbolTable:
-    def __init__(self, symbols, bases):
+    def __init__(self, symbols, bases, globals):
         self._symbols = symbols
         self._bases = bases
+        self._globals = globals
         self._pass = None
 
     def set_pass(self, _pass):
@@ -53,7 +54,9 @@ def dump(self):
             print(symbol, entry)
 
     def export(self):
-        addrs_syms = [(self.resolve_absolute(entry), symbol) for symbol, entry in self._symbols.items()]
+        addrs_syms = [(self.resolve_absolute(entry), symbol)
+                      for symbol, entry in self._symbols.items()
+                      if symbol in self._globals]
         return sorted(addrs_syms)
 
     def to_abs_addr(self, section, offset):
@@ -93,11 +96,15 @@ def resolve_relative(self, symbol):
         from_addr = self.to_abs_addr(self._from_section, self._from_offset)
         return sym_addr - from_addr
 
+    def set_global(self, symbol):
+        self._globals[symbol] = True
+        pass
+
 
 class Assembler:
 
-    def __init__(self, symbols=None, bases=None):
-        self.symbols = SymbolTable(symbols or {}, bases or {})
+    def __init__(self, symbols=None, bases=None, globls=None):
+        self.symbols = SymbolTable(symbols or {}, bases or {}, globls or {})
         opcodes.symbols = self.symbols  # XXX dirty hack
 
     def init(self, a_pass):
@@ -236,6 +243,9 @@ def d_set(self, symbol, expr):
         value = int(expr)  # TODO: support more than just integers
         self.symbols.set_sym(symbol, ABS, None, value)
 
+    def d_global(self, symbol):
+        self.symbols.set_global(symbol)
+
     def append_data(self, wordlen, args):
         data = [int(arg).to_bytes(wordlen, 'little') for arg in args]
         self.append_section(b''.join(data))

tests/assemble.py

@@ -22,6 +22,23 @@
 """
 
 
+src_global = """\
+
+  .global counter
+counter:
+  .long 0
+
+internal:
+  .long 0
+
+  .text
+  .global entry
+entry:
+  wait 42
+  halt
+"""
+
+
 def test_parse_line():
     a = Assembler()
     lines = iter(src.splitlines())
@@ -90,8 +107,19 @@ def test_assemble_bss_with_value():
     assert raised
 
 
+def test_assemble_global():
+    a = Assembler()
+    a.assemble(src_global)
+    assert a.symbols.has_sym('counter')
+    assert a.symbols.has_sym('internal')
+    assert a.symbols.has_sym('entry')
+
+    exported_symbols = a.symbols.export()
+    assert exported_symbols == [(0, 'counter'), (2, 'entry')]  # internal not exported
+
+
 def test_symbols():
-    st = SymbolTable({}, {})
+    st = SymbolTable({}, {}, {})
     for entry in [
         ('rel_t4', REL, TEXT, 4),
         ('abs_t4', ABS, TEXT, 4),
@@ -148,4 +176,5 @@ def test_symbols():
 test_assemble()
 test_assemble_bss()
 test_assemble_bss_with_value()
+test_assemble_global()
 test_symbols()