VM safety: missing failing guards in SmartSyntaxPlugin - Vm-dev

1 Apr 2015


      Hi again,
with clang analyzer I noticed a bunch of failing guards missing.
For example, take this one:
[image: Images intégrées 1]This code comes from:
primitiveSocketConnectionStatus: socket
| s status |
    <var: #s type: 'SocketPtr '>
    self primitive: 'primitiveSocketConnectionStatus'
        parameters: #(Oop).
    s := self socketValueOf: socket.
    interpreterProxy failed ifFalse: [
        status := self sqSocketConnectionStatus: s].
    ^ status asSmallIntegerObj
Maybe it's innocuous to generate an integerObjectOf:
somethingNotInitialized, but who knows what more dangerous expression might
be returned...
This is the SmartSyntaxPluginCodeGenerator at work.
looking at this SmartSyntaxPluginTMethod method, I feel like it is a
missing guard near the bottom, find correction attached:
fixUpReturnOneStmt: stmt on: sStream
stmt isReturn ifFalse: [^sStream nextPut: stmt].
    (stmt expression isSend
     and: [#('primitiveFail' 'primitiveFailFor:') includes: stmt expression
selector]) ifTrue:
        ["failure return"
         sStream nextPut: stmt expression.
         sStream nextPut: self nullReturnExpr.
         ^nil].
    (stmt expression isVariable and: ['nil' = stmt expression name])
ifTrue:
        ["^ nil -- this is never right unless automatically generated"
         sStream nextPut: stmt.
         ^nil].
    (stmt expression isVariable and: ['self' = stmt expression name])
ifTrue:
        ["^ self"
         self generateFailureGuardOn: sStream.
         fullArgs isEmpty ifFalse:[ sStream nextPut: (self popExpr:
fullArgs size)].
         sStream nextPut: self nullReturnExpr.
         ^nil].
    (stmt expression isVariable | stmt expression isConstant |
suppressingFailureGuards) ifTrue:
        ["^ variable or ^ constant or ^ expr without guardchecking"
         self generateFailureGuardOn: sStream.
         sStream nextPut: (self pop: fullArgs size + 1 thenReturnExpr: stmt
expression).
         sStream nextPut: self nullReturnExpr.
         ^nil].
    "^ expr with guardchecking"
"vvvvvv LOOK HERE vvvvvvvvvvvvvv"
          self generateFailureGuardOn: sStream.
          "^^^^^^ THIS GUARD WAS MISSING I HAD TO ADD IT"
sStream nextPut: (self assign: (self oopVariable: '_return_value')
expression: stmt expression).
    self generateFailureGuardOn: sStream.
    sStream nextPut: (self pop: fullArgs size + 1 thenReturnExpr: (self
oopVariable: '_return_value')).
    sStream nextPut: self nullReturnExpr