radare2/doc/kvast.md

kvast

KeyValue storage for AST

To optimize serialized storage use a concatenated string array and use the sdb array string api

eax=33

0.op=set     []0=set,eax,33
0.a=eax
0.b=33

ebx=(8*(eax+4))

0.op=set     []0=set,ebx,$1
0.a=ebx
0.b=$1

1.op=mul     []1=mul,8,$2
1.a=8
1.b=$2

2.op=add     []2=add,eax,4
2.a=eax
2.b=4

ebx=8*(eax+4)+3

0.op=set     []0=set,ebx,$3
0.a=ebx
0.b=$3

1.op=mul     []1=mul,8,$2
1.a=8
1.b=$2

2.op=add     []2=add,eax,4
2.a=eax
2.b=4

3.op=add     []3=add,$1,3
3.a=$1
3.b=3

ebx=8*(eax+4+ecx+2)+1

0.op=set
0.a=ebx
0.b=$5

1.op=mul
1.a=8
1.b=$4

( 2.op=add 2.a=eax 2.b=4

// update toplevel b reference 3.op=add 3.a=$2 3.b=ecx

// update toplevel b reference 4.op=add 4.a=$3 4.b=2 }

// update toplevel b reference 5.op=add 5.a=$1 5.b=1

Parsing

Parsing is done by a state machine which reads the expression string and creates a keyvalue string that represents the ESIL instruction.

This is an example

	switch (ch) {
	case '+':
	case '-':
	case '*':
	case '/':
		if (expect_arg) {
			expect_arg = ch;
		}
		break;
	}