"

jv:vdb - Visual / VM Debugger

Copyright (C) 2015-now Jan Vrany

This software is licensed under 'Creative Commons Attribution-NonCommercial 4.0 International License'

You may find a full license text in LICENSE.txt or at http://creativecommons.org/licenses/by-nc/4.0/

"

"{ Package: 'jv:vdb' }"

"{ NameSpace: Smalltalk }"

Object subclass:#VDBInstructionBasicBlock

	instanceVariableNames:'instructions precedessors successor1 successor2'

	classVariableNames:''

	poolDictionaries:''

	category:'VDB-UI-Support'

!

!VDBInstructionBasicBlock class methodsFor:'documentation'!

copyright

"

jv:vdb - Visual / VM Debugger

Copyright (C) 2015-now Jan Vrany

This software is licensed under 'Creative Commons Attribution-NonCommercial 4.0 International License'

You may find a full license text in LICENSE.txt or at http://creativecommons.org/licenses/by-nc/4.0/

"

! !

!VDBInstructionBasicBlock class methodsFor:'utilities'!

analyze: instructions

    "

    Analyzes `instructions`, create and connect basic blocks and return

    them in a collection.

    `instructions` parameter should be a list of GDBInstruction or 

    polymorphic objects).

    "

    | blocks curBB firstI |

    "/ Pass 1, initial blocks by cutting after each branch

    "/ or return instruction.

    blocks := OrderedCollection new.

    curBB := VDBInstructionBasicBlock new.

    instructions withIndexDo:[:last :lastI | 

        firstI isNil ifTrue:[

            firstI := lastI

        ].

        last isBranchInstruction ifTrue:[

            | prevBB |

            curBB setInstructions: (instructions copyFrom: firstI to: lastI).

            blocks add: curBB.

            prevBB := curBB.

            curBB := VDBInstructionBasicBlock new.

            prevBB setSuccessor1: curBB.

            firstI := nil.

        ] ifFalse:[

        last isReturnInstruction ifTrue:[

            curBB setInstructions: (instructions copyFrom: firstI to: lastI).

            blocks add: curBB.

            curBB := VDBInstructionBasicBlock new.

            firstI := nil.

        ]].

    ].

    curBB setInstructions: (instructions copyFrom: firstI).

    blocks add: curBB.

    "/ Pass 2: iterate ober basic blocks and connect successor2 based on

    "/ last instructions #branchTargetAddress. If target address points in

    "/ the middle of basic block, split it.

    blocks copy do:[:bb | 

        bb last isBranchInstruction ifTrue:[

            | targetAddress succBB |

            targetAddress := bb last branchTargetAddress.

            "/ Find successor block. Note, that we may found none if the branch target is

            "/ outside given coce.

            succBB := blocks detect:[:e | e includesAddress: targetAddress ] ifNone: [ nil ].

            succBB notNil ifTrue:[ 

                "/ If `targetAddress` points into the middle of `succBB` we have to split

                "/ succBB into two.

                succBB firstAddress < targetAddress ifTrue:[ 

                    | succBBs |

                    succBBs := succBB splitAtAddress: targetAddress.

                    blocks remove: succBB; addAll: succBBs.

                    succBB := succBBs last.

                ].

                bb setSuccessor2: succBB.

            ].

        ].

    ].

    "/ Jo done!!

    ^ blocks.

    ^ blocks

    "Created: / 27-06-2018 / 13:03:16 / Jan Vrany <jan.vrany@fit.cvut.cz>"

    "Modified: / 27-06-2018 / 16:13:17 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!VDBInstructionBasicBlock methodsFor:'accessing'!

first

    ^ instructions first

    "Created: / 27-06-2018 / 15:41:58 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

firstAddress

    ^ self first address

    "Created: / 27-06-2018 / 15:41:34 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

last

    ^ instructions last

    "Created: / 27-06-2018 / 15:42:09 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

lastAddress

    ^ self last address

    "Created: / 27-06-2018 / 15:41:38 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!VDBInstructionBasicBlock methodsFor:'initialization'!

addPrecedessor: aVDBInstructionBlock

    precedessors isNil ifTrue:[ 

        precedessors := Array with: aVDBInstructionBlock.

    ] ifFalse:[ 

        precedessors := precedessors copyWith: aVDBInstructionBlock

    ].

    "Created: / 27-06-2018 / 15:29:27 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

setInstructions: aCollection

    instructions := aCollection

    "Created: / 27-06-2018 / 14:59:31 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

setSuccessor1: aVDBInstructionBasicBlock

    successor1 := aVDBInstructionBasicBlock.

    successor1 addPrecedessor: self.

    "Created: / 27-06-2018 / 15:28:21 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

setSuccessor2: aVDBInstructionBasicBlock

    successor2 := aVDBInstructionBasicBlock.

    successor2 addPrecedessor: self.

    "Created: / 27-06-2018 / 15:28:27 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!VDBInstructionBasicBlock methodsFor:'queries'!

includes: instruction

    ^ instructions includes: instruction

    "Created: / 27-06-2018 / 15:37:23 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

includesAddress: address

    "Return `true`, if this basic block includes an instruction

     with given address, false otherwise."

    ^ (address between: instructions first address and: instructions last address)

    "Created: / 27-06-2018 / 15:40:55 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!VDBInstructionBasicBlock methodsFor:'utilities'!

splitAtAddress: address

    | splitIdx bb1 bb2 |

    splitIdx := instructions indexOf: (instructions detect:[:e | e address = address ] ifNone:[ nil ]).

    "/ Note, that thhere might not be any instruction with that address, such as

    "/ when ill-code jumps into the middle of instruction...

    splitIdx == 0 ifTrue:[ 

        "/ ...in that case, make no split and return self so this case is 

        "/ transparent to users.

        ^Array with: self.

    ].

    bb1 := self class new setInstructions: (instructions copyTo: splitIdx - 1).

    bb2 := self class new setInstructions: (instructions copyFrom: splitIdx).

    bb1 setSuccessor1: bb2.

    ^ Array with: bb1 with: bb2.

    "Created: / 27-06-2018 / 16:00:17 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!VDBInstructionBasicBlock class methodsFor:'documentation'!

version_HG

    ^ '$Changeset: <not expanded> $'

! !