Support "la $reg, (SYMBOL)"

m2c/asm_instruction.py

@@ -324,13 +324,18 @@ def expect(n: str) -> str:
                 value = constant_fold(rhs, defines)
             else:
                 # Address mode.
-                assert top_level
                 rhs = replace_bare_reg(rhs, arch, reg_formatter)
                 if rhs == AsmLiteral(0):
                     rhs = Register("zero")
-                assert isinstance(rhs, Register)
-                value = constant_fold(value or AsmLiteral(0), defines)
-                value = AsmAddressMode(value, rhs)
+                if isinstance(rhs, AsmGlobalSymbol):
+                    # Global symbols may be parenthesized.
+                    assert value is None
+                    value = constant_fold(rhs, defines)
+                else:
+                    assert top_level
+                    assert isinstance(rhs, Register)
+                    value = constant_fold(value or AsmLiteral(0), defines)
+                    value = AsmAddressMode(value, rhs)
         elif tok == '"':
             # Quoted global symbol.
             expect('"')

tests/end_to_end/weird-asm/test-out.c

@@ -1,5 +1,7 @@
 Warning: missing "jr $ra" in last block (jumptarget_label).
 
+extern ? some_symbol;
+
 s32 test(void) {
     return 0x1233FFFF * 2;
 }

tests/end_to_end/weird-asm/test.s

@@ -21,6 +21,7 @@ b jumptarget_label
  li $two, 2 # fictive register names are (currently) fine
 jlabel jumptarget_label
 multu $v0, $v0, $two # multiply by two, ps2-style
+la $v1, (some_symbol)
 addiu $sp, $sp, 0x34
 
 func_other: