On 06 Dec 2013, at 10:01, Roberto Minelli <[email protected]> wrote:
> Hi guys,
>
> I am using Spy for my project, and I need to do something which, on top of my
> knowledge, is not supported.
>
> Here is the point: Spy allows to insert code before (#beforeRun:with:in:) and
> after (#afterRun:with:in:) and works perfectly.
>
> Now suppose I want to inject some code *inside* the method, e.g.,
>
> aMethodToBeProfiled
>
> do something
>
> "Injected code accessing some fields of the current instance of this
> object”
> Transcript show: self field asString.
>
> Is there any support for this?
>
Here is how to do it on the IR level:
A class TestMy with
test
^x + 1 + x
byte code is:
13 <00> pushRcvr: 0
14 <76> pushConstant: 1
15 <B0> send: +
16 <00> pushRcvr: 0
17 <B0> send: +
18 <7C> returnTop
“get a copy of the IR tree"
irMethod := (TestMy>>#test) ir copy.
“get all instance variable access IR instructions”
allIvarAccesses := irMethod allInstructionsMatching: [ :ir |ir
isInstVarAccess].
“insert code for “1 halt” before all of them"
allIvarAccesses do: [ :each | each addInstructionsBefore: { IRInstruction
pushLiteral: 1. IRInstruction send: #halt. IRInstruction popTop }].
“generate a new compiledMethod"
cm := irMethod generate: (TestMy>>#test) trailer.
“install in the class"
TestMy addSelector: #test withMethod: cm.
17 <76> pushConstant: 1
18 <D0> send: halt
19 <87> pop
20 <00> pushRcvr: 0
21 <76> pushConstant: 1
22 <B0> send: +
23 <76> pushConstant: 1
24 <D0> send: halt
25 <87> pop
26 <00> pushRcvr: 0
27 <B0> send: +
28 <7C> returnTop
—> TestMy new test
What is now yet wiring is quick return methods —> need to clear the primitive
in that case, should not be hard to do.
