On 29 Nov 2016, at 13:04, Clément Bera <bera.clement@gmail.com> wrote:


Can you confirm this bug happen only in Windows ?

yes, the crash is just in windows.
the callback problem is general (note that FFICallbackTests works fine, but I think this is related to the fact that it never enters the 2nd condition with the qsort function) .

Do you have version number (both VMMaker and git commit) of the last version you have that was working ?

sadly, not… I tried to get the latest working version, but with the mess I have to get the VM to build with opensmalltalk-vm, I couldn’t track it. 
I suspect is related to the work on 64bits for windows, but I have no proof of that :P



On Tue, Nov 29, 2016 at 11:54 AM, Esteban Lorenzano <estebanlm@gmail.com> wrote:


So, I’m building the PharoVM along with all his dependencies. For me, this is a major step because I can drop the old build process finally.
Now, I’m having serious problems with FFI (that they were not present before), :

1. CRASH IN WINDOWS (32bits):

In Win32, it crashes automatically when trying to access this funtion:

getEnvSize: nameString
        ^ self ffiCall: #( int GetEnvironmentVariableA ( String nameString, nil, 0 ) ) module: #Kernel32

 (this works perfectly fine in older versions)


Callbacks have problems. The examples passes but they are very simple… as soon as I try to do something complicates (like unqlite bindings or libgit2 bindings, who use callbacks intensively), callbacks stops working.
I traced the problem up to this method:


returnAs: returnTypeOop ThroughCallback: vmCallbackContext Context: callbackMethodContext
        "callbackMethodContext is an activation of invokeCallback:[stack:registers:jmpbuf:].
         Its sender is the VM's state prior to the callback.  Reestablish that state (via longjmp),
         and mark callbackMethodContext as dead."
        <export: true>
        <var: #vmCallbackContext type: #'VMCallbackContext *'>
        | calloutMethodContext theFP thePage |
        <var: #theFP type: #'char *'>
        <var: #thePage type: #'StackPage *'>
        ((self isIntegerObject: returnTypeOop)
         and: [self isLiveContext: callbackMethodContext]) ifFalse:
        calloutMethodContext := self externalInstVar: SenderIndex ofContext: callbackMethodContext.
        (self isLiveContext: calloutMethodContext) ifFalse:
        "We're about to leave this stack page; must save the current frame's instructionPointer."
        self push: instructionPointer.
        self externalWriteBackHeadFramePointers.
        "Mark callbackMethodContext as dead; the common case is that it is the current frame.
         We go the extra mile for the debugger."
        (self isSingleContext: callbackMethodContext)
                ifTrue: [self markContextAsDead: callbackMethodContext]
                        [theFP := self frameOfMarriedContext: callbackMethodContext.
                         framePointer = theFP "common case"
                                        [(self isBaseFrame: theFP)
                                                ifTrue: [stackPages freeStackPage: stackPage]
                                                ifFalse: "calloutMethodContext is immediately below on the same page.  Make it current."
                                                        [instructionPointer := (self frameCallerSavedIP: framePointer) asUnsignedInteger.
                                                         stackPointer := framePointer + (self frameStackedReceiverOffset: framePointer) + objectMemory wordSize.
                                                         framePointer := self frameCallerFP: framePointer.
                                                         self setMethod: (self frameMethodObject: framePointer).
                                                         self restoreCStackStateForCallbackContext: vmCallbackContext.
                                                         "N.B. siglongjmp is defines as _longjmp on non-win32 platforms.
                                                          This matches the use of _setjmp in ia32abicc.c."
                                                         self siglong: vmCallbackContext trampoline jmp: (self integerValueOf: returnTypeOop).
                                        [self externalDivorceFrame: theFP andContext: callbackMethodContext.
                                         self markContextAsDead: callbackMethodContext]].
        "Make the calloutMethodContext the active frame.  The case where calloutMethodContext
         is immediately below callbackMethodContext on the same page is handled above."
        (self isStillMarriedContext: calloutMethodContext)
                        [theFP := self frameOfMarriedContext: calloutMethodContext.
                         thePage := stackPages stackPageFor: theFP.
                         "findSPOf:on: points to the word beneath the instructionPointer, but
                          there is no instructionPointer on the top frame of the current page."
                         self assert: thePage ~= stackPage.
                         stackPointer := (self findSPOf: theFP on: thePage) - objectMemory wordSize.
                         framePointer := theFP]
                        [thePage := self makeBaseFrameFor: calloutMethodContext.
                         framePointer := thePage headFP.
                         stackPointer := thePage headSP].
        instructionPointer := self popStack.
        self setMethod: (objectMemory fetchPointer: MethodIndex ofObject: calloutMethodContext).
        self setStackPageAndLimit: thePage.
        self restoreCStackStateForCallbackContext: vmCallbackContext.
         "N.B. siglongjmp is defines as _longjmp on non-win32 platforms.
          This matches the use of _setjmp in ia32abicc.c."
        self siglong: vmCallbackContext trampoline jmp: (self integerValueOf: returnTypeOop).

with the first siglongjmp callbacks are passing fine.
with the last (it would be if  framePointer = theFP AND !(isBaseFrame: theFP) ) it doesn’t.

So… from here I’m a bit lost… I need some help :)