wasm instumentation examples

balance.wat

(module
	(import "seal0" "seal_balance" (func $seal_balance (param i32 i32)))
	(import "env" "memory" (memory 1 1))
	;; [0, 8) reserved for $seal_balance output
	;; [8, 16) length of the buffer for $seal_balance
	;; [16, inf) zero initialized
	(data (i32.const 8) "\08")
	;; Utility function for making assertions.
	(func $assert (param i32)
		(block $ok
			(br_if $ok
				(local.get 0)
			)
			(unreachable)))
	;; Contract constructor
	(func (export "deploy"))
	;; Contract call
	(func (export "call")
		(call $seal_balance (i32.const 0) (i32.const 8))
		;; Balance should be encoded as a u64.
		(call $assert
			(i32.eq
				(i32.load (i32.const 8))
				(i32.const 8)))
		;; Assert the free balance to be zero.
		(call $assert
			(i64.eq
				(i64.load (i32.const 0))
				(i64.const 0)))))

balance_d.wat

(module
  (type (;0;) (func (param i32 i32)))
  (type (;1;) (func (param i32)))
  (type (;2;) (func))
  (import "seal0" "seal_balance" (func (;0;) (type 0)))
  (import "env" "memory" (memory (;0;) 1 1))
  (func (;1;) (type 1) (param i32)
    block  ;; label = @1
      local.get 0
      br_if 0 (;@1;)
      unreachable
    end)
  (func (;2;) (type 2))
  (func (;3;) (type 2)
    i32.const 0
    i32.const 8
    call 0
    i32.const 8
    i32.load
    i32.const 8
    i32.eq
    call 1
    i32.const 0
    i64.load
    i64.const 0
    i64.eq
    call 1)
  (export "deploy" (func 2))
  (export "call" (func 3))
  (data (;0;) (i32.const 8) "\08"))

balance_i.wat

(module
  (type (;0;) (func (param i32 i32)))
  (type (;1;) (func (param i32)))
  (type (;2;) (func))
  (type (;3;) (func (param i64)))
  (import "seal0" "seal_balance" (func (;0;) (type 0)))
  (import "env" "memory" (memory (;0;) 1 1))
  (import "env" "gas" (func (;1;) (type 3)))
  (func (;2;) (type 1) (param i32)
    i64.const 3
    call 1
    block  ;; label = @1
      local.get 0
      br_if 0 (;@1;)
      i64.const 1
      call 1
      unreachable
    end)
  (func (;3;) (type 2))
  (func (;4;) (type 2)
    i64.const 13
    call 1
    i32.const 0
    i32.const 8
    call 0
    i32.const 8
    i32.load
    i32.const 8
    i32.eq
    call 2
    i32.const 0
    i64.load
    i64.const 0
    i64.eq
    call 2)
  (export "deploy" (func 3))
  (export "call" (func 4))
  (data (;0;) (i32.const 8) "\08"))

balance_i_mut_global.wat

(module
  (type (;0;) (func (param i32 i32)))
  (type (;1;) (func (param i32)))
  (type (;2;) (func))
  (type (;3;) (func (param i64)))
  (import "seal0" "seal_balance" (func (;0;) (type 0)))
  (import "env" "memory" (memory (;0;) 1 1))
  (func (;1;) (type 1) (param i32)
    i64.const 14
    call 4
    block  ;; label = @1
      local.get 0
      br_if 0 (;@1;)
      i64.const 12
      call 4
      unreachable
    end)
  (func (;2;) (type 2))
  (func (;3;) (type 2)
    i64.const 24
    call 4
    i32.const 0
    i32.const 8
    call 0
    i32.const 8
    i32.load
    i32.const 8
    i32.eq
    call 1
    i32.const 0
    i64.load
    i64.const 0
    i64.eq
    call 1)
  (func (;4;) (type 3) (param i64)
    global.get 0
    local.get 0
    i64.ge_u
    if  ;; label = @1
      global.get 0
      local.get 0
      i64.sub
      global.set 0
    else
      i64.const -1
      global.set 0
      unreachable
    end)
  (global (;0;) (mut i64) (i64.const 0))
  (export "deploy" (func 2))
  (export "call" (func 3))
  (export "gas_left" (global 0))
  (data (;0;) (i32.const 8) "\08"))

local_gas_fn.wat

(func $gas (param i64)
    global.get 0
    local.get 0
    i64.ge_u
    if
      global.get 0
      local.get 0
      i64.sub
      global.set 0
    else
      i64.const -1
      global.set 0
      unreachable
    end)