[sdcc-devel] AST level & block explanation

[Åke R. <ake...@gm...>]

Hello All!

If some kind soul could donate some time to explain. Looking at 
generated AST i wonder what levels and blocks are. Specifically why "ni" 
symbol has L2 B3 in (block???) L2 B4 ?

/Ake

Example:

FUNCTION (_dummy=0x6000f39b0) type (int fixed) args (int auto)
tree (0x6000f3910) not decorated
(null):0:{ L1 B2
(null):0:  DECLARE SYMBOL (L1 B2 n=0x6000eda30) type (int auto)
(null):0:  { L2 B4
(null):0:    DECLARE SYMBOL (L2 B3 ni=0x6000ee1e0) type (int auto)
(null):0:    LABEL (0x6000f2f80)
test6.c:0:      SYMBOL (L3 B4 _forcond_0=0x6000f2ee0 @ 0x6000ef250)
test6.c:0:    IF (0x6000f2920)
test6.c:6:      LT(<) (0x6000efa20) type (_Bool fixed)
test6.c:6:        SYMBOL (L1 B1 x=0x6000ed8e0 @ 0x6000ed0d0) type (int auto)
test6.c:6:        CONSTANT (0x6000ef980) value = 0, 0x0, 0.000000 type 
(const-unsigned-char literal)
test6.c:0:      NE(!=) 0 goto _forbreak_0
test6.c:0:      EQ(==) 0 goto _forbody_0
(null):0:    LABEL (0x6000f2c50)
test6.c:0:      SYMBOL (L3 B4 _forbody_0=0x6000f2bb0 @ 0x6000ef000)
test6.c:7:    ASSIGN(=) (0x6000f0a00) type (int auto)
test6.c:7:      SYMBOL (L2 B3 ni=0x6000f02a0 @ 0x6000ee1e0) type (int auto)
test6.c:7:      SUB (0x6000f0960) type (int register)
test6.c:7:        SYMBOL (L2 B3 ni=0x6000f0690 @ 0x6000ee1e0) type (int 
auto)
test6.c:7:        CONSTANT (0x6000f1cb0) value = 2, 0x2, 2.000000 type 
(int literal)
(null):0:    LABEL (0x6000f3590)
test6.c:0:      SYMBOL (L3 B4 _forcontinue_0=0x6000f34f0 @ 0x6000eeb60)
test6.c:6:    post-DEC_OP (0x6000efeb0) type (int auto)
test6.c:6:      SYMBOL (L1 B1 x=0x6000efe10 @ 0x6000ed0d0) type (int auto)
test6.c:0:    GOTO (0x6000f31c0)
test6.c:0:      SYMBOL (L3 B4 _forcond_0=0x6000f3120 @ 0x6000ef250)
(null):0:    LABEL (0x6000f0dd0)
test6.c:0:      SYMBOL (L3 B4 _forbreak_0=0x6000f0d30 @ 0x6000eedb0)
(null):0:  }
test6.c:9:  RETURN (0x6000f13a0) type (int auto)
test6.c:9:    SYMBOL (L1 B2 n=0x6000f1300 @ 0x6000eda30) type (int auto)
(null):0:}

int dummy(int x)
{
    int n = 0;
    {
    int ni = 10;
    for (;x>=0;x--)
      ni = ni - 2;
    }
    return n;
}