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CFG: Remove isHidden() predicate

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This commit is contained in:
Tom Hvitved
2021-03-24 15:43:50 +01:00
parent d103acb04f
commit ca7c0584c7
1 changed files with 100 additions and 114 deletions
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214
ql/src/codeql_ruby/controlflow/internal/ControlFlowGraphImpl.qll
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@@ -107,12 +107,6 @@ abstract private class ControlFlowTree extends AstNode {
*/
pragma[nomagic]
abstract predicate succ(AstNode pred, AstNode succ, Completion c);
/**
* Holds if this node should be hidden in the CFG. That is, edges
* `pred -> this -> succ` are converted to a single edge `pred -> succ`.
*/
predicate isHidden() { none() }
}
/** Holds if `first` is the first element executed within AST node `n`. */
@@ -132,62 +126,35 @@ predicate last(ControlFlowTree n, AstNode last, Completion c) {
)
}
private predicate succImpl(AstNode pred, AstNode succ, Completion c) {
any(ControlFlowTree cft).succ(pred, succ, c)
}
private predicate isHidden(ControlFlowTree t) { t.isHidden() }
private predicate succImplIfHidden(AstNode pred, AstNode succ) {
isHidden(pred) and
succImpl(pred, succ, any(SimpleCompletion c))
}
/**
* Holds if `succ` is a control flow successor for `pred`, given that `pred`
* finishes with completion `c`.
*/
pragma[nomagic]
predicate succ(AstNode pred, AstNode succ, Completion c) {
exists(AstNode n |
succImpl(pred, n, c) and
succImplIfHidden*(n, succ) and
not isHidden(pred) and
not isHidden(succ)
)
any(ControlFlowTree cft).succ(pred, succ, c)
}
/** Holds if `first` is first executed when entering `scope`. */
pragma[nomagic]
predicate succEntry(CfgScope::Range_ scope, AstNode first) {
exists(AstNode n |
scope.entry(n) and
succImplIfHidden*(n, first) and
not isHidden(first)
)
}
predicate succEntry(CfgScope::Range_ scope, AstNode first) { scope.entry(first) }
/** Holds if `last` with completion `c` can exit `scope`. */
pragma[nomagic]
predicate succExit(CfgScope::Range_ scope, AstNode last, Completion c) {
exists(AstNode n |
scope.exit(n, c) and
succImplIfHidden*(last, n) and
not isHidden(last)
)
}
predicate succExit(CfgScope::Range_ scope, AstNode last, Completion c) { scope.exit(last, c) }
/**
* An AST node where the children are evaluated following a standard left-to-right
* evaluation. The actual evaluation order is determined by the predicate
* `getChildNode()`.
*/
abstract private class StandardNode extends ControlFlowTree {
abstract private class StandardTree extends ControlFlowTree {
/** Gets the `i`th child node, in order of evaluation. */
abstract ControlFlowTree getChildNode(int i);
private AstNode getChildNodeRanked(int i) {
result = rank[i + 1](AstNode child, int j | child = this.getChildNode(j) | child order by j)
private ControlFlowTree getChildNodeRanked(int i) {
result =
rank[i + 1](ControlFlowTree child, int j | child = this.getChildNode(j) | child order by j)
}
/** Gets the first child node of this element. */
@@ -236,24 +203,17 @@ private class ForRange extends ForExpr {
}
}
// TODO: remove this predicate
predicate isValidFor(Completion c, ControlFlowTree node) {
c instanceof SimpleCompletion and isHidden(node)
or
c.isValidFor(node)
}
abstract private class StandardPreOrderTree extends StandardNode, PreOrderTree {
abstract private class StandardPreOrderTree extends StandardTree, PreOrderTree {
final override predicate last(AstNode last, Completion c) {
last(this.getLastChildNode(), last, c)
or
not exists(this.getLastChildNode()) and
isValidFor(c, this) and
c.isValidFor(this) and
last = this
}
final override predicate succ(AstNode pred, AstNode succ, Completion c) {
StandardNode.super.succ(pred, succ, c)
StandardTree.super.succ(pred, succ, c)
or
pred = this and
first(this.getFirstChildNode(), succ) and
@@ -264,11 +224,11 @@ abstract private class StandardPreOrderTree extends StandardNode, PreOrderTree {
abstract private class PostOrderTree extends ControlFlowTree {
override predicate last(AstNode last, Completion c) {
last = this and
isValidFor(c, last)
c.isValidFor(last)
}
}
abstract private class StandardPostOrderTree extends StandardNode, PostOrderTree {
abstract private class StandardPostOrderTree extends StandardTree, PostOrderTree {
final override predicate first(AstNode first) {
first(this.getFirstChildNode(), first)
or
@@ -277,7 +237,7 @@ abstract private class StandardPostOrderTree extends StandardNode, PostOrderTree
}
final override predicate succ(AstNode pred, AstNode succ, Completion c) {
StandardNode.super.succ(pred, succ, c)
StandardTree.super.succ(pred, succ, c)
or
last(this.getLastChildNode(), pred, c) and
succ = this and
@@ -291,11 +251,11 @@ abstract private class LeafTree extends PreOrderTree, PostOrderTree {
override predicate succ(AstNode pred, AstNode succ, Completion c) { none() }
}
abstract class ScopeTree extends StandardNode, LeafTree {
abstract class ScopeTree extends StandardTree, LeafTree {
final override predicate propagatesAbnormal(AstNode child) { none() }
final override predicate succ(AstNode pred, AstNode succ, Completion c) {
StandardNode.super.succ(pred, succ, c)
StandardTree.super.succ(pred, succ, c)
}
}
@@ -309,10 +269,14 @@ module Trees {
}
}
private class ArgumentListTree extends StandardPostOrderTree, ArgumentList {
private class ArgumentListTree extends StandardTree, ArgumentList {
final override ControlFlowTree getChildNode(int i) { result = this.getElement(i) }
override predicate isHidden() { any() }
final override predicate first(AstNode first) { first(this.getFirstChildNode(), first) }
final override predicate last(AstNode last, Completion c) {
last(this.getLastChildNode(), last, c)
}
}
private class ArrayLiteralTree extends StandardPostOrderTree, ArrayLiteral {
@@ -335,8 +299,10 @@ module Trees {
}
}
private class BeginTree extends BodyStmtPreOrderTree, BeginExpr {
override predicate isHidden() { any() }
private class BeginTree extends BodyStmtTree, BeginExpr {
final override predicate first(AstNode first) { this.firstInner(first) }
final override predicate last(AstNode last, Completion c) { this.lastInner(last, c) }
}
private class BinaryOperationTree extends StandardPostOrderTree, BinaryOperation {
@@ -416,11 +382,6 @@ module Trees {
}
override predicate succ(AstNode pred, AstNode succ, Completion c) {
this instanceof PreOrderTree and
pred = this and
c instanceof SimpleCompletion and
this.firstInner(succ)
or
// Normal left-to-right evaluation in the body
exists(int i |
last(this.getBodyChild(i, _), pred, c) and
@@ -498,12 +459,14 @@ module Trees {
* Gets a descendant that belongs to the `ensure` block of this block, if any.
* Nested `ensure` blocks are not included.
*/
pragma[nomagic]
AstNode getAnEnsureDescendant() {
result = this.getEnsure()
or
exists(AstNode mid |
mid = this.getAnEnsureDescendant() and
result = getAChildInScope(mid, getCfgScope(mid)) and
result = mid.getAChild() and
getCfgScope(result) = getCfgScope(mid) and
not exists(BodyStmt nestedBlock |
result = nestedBlock.getEnsure() and
nestedBlock != this
@@ -517,7 +480,8 @@ module Trees {
*/
private predicate nestedEnsure(BodyStmtTree innerBlock) {
exists(StmtSequence innerEnsure |
innerEnsure = getAChildInScope(this.getAnEnsureDescendant(), getCfgScope(this)) and
innerEnsure = this.getAnEnsureDescendant().getAChild() and
getCfgScope(innerEnsure) = getCfgScope(this) and
innerEnsure = innerBlock.(BodyStmt).getEnsure()
)
}
@@ -565,7 +529,15 @@ module Trees {
or
not exists(this.getAChild(_)) and
last = this and
isValidFor(c, this)
c.isValidFor(this)
}
final override predicate succ(AstNode pred, AstNode succ, Completion c) {
BodyStmtTree.super.succ(pred, succ, c)
or
pred = this and
c instanceof SimpleCompletion and
this.firstInner(succ)
}
}
@@ -1041,7 +1013,7 @@ module Trees {
or
not exists(this.getAnException()) and
last = this and
isValidFor(c, this)
c.isValidFor(this)
)
)
}
@@ -1127,7 +1099,30 @@ module Trees {
final override predicate first(AstNode first) { first(this.getStmt(0), first) }
override predicate propagatesAbnormal(AstNode child) { child = this.getAStmt() }
final override predicate propagatesAbnormal(AstNode child) { child = this.getAStmt() }
final override predicate succ(AstNode pred, AstNode succ, Completion c) {
succ = this and
last(this.getLastBodyChild(), pred, c) and
c instanceof NormalCompletion
or
StmtSequenceTree.super.succ(pred, succ, c)
}
}
private class TSimpleHiddenStmtSequenceTree =
ASTInternal::TElse or ASTInternal::TThen or ASTInternal::TDo;
private class SimpleHiddenStmtSequenceTree extends StmtSequenceTree, TSimpleHiddenStmtSequenceTree {
final override predicate propagatesAbnormal(AstNode child) { child = this.getAStmt() }
final override predicate first(AstNode first) { first(this.getStmt(0), first) }
final override predicate last(AstNode last, Completion c) { last(this.getLastStmt(), last, c) }
final override predicate succ(AstNode pred, AstNode succ, Completion c) {
StmtSequenceTree.super.succ(pred, succ, c)
}
}
/**
@@ -1142,28 +1137,25 @@ module Trees {
not this instanceof EndBlock and
not this instanceof StringInterpolationComponent and
not this instanceof Block and
not this instanceof ParenthesizedExpr
not this instanceof ParenthesizedExpr and
not this instanceof TSimpleHiddenStmtSequenceTree
}
override predicate propagatesAbnormal(AstNode child) { child = this.getAStmt() }
override predicate isHidden() {
this instanceof ASTInternal::TElse or
this instanceof ASTInternal::TThen or
this instanceof ASTInternal::TDo
}
final AstNode getLastChildNode() { result = this.getStmt(this.getNumberOfStatements() - 1) }
final override predicate propagatesAbnormal(AstNode child) { child = this.getAStmt() }
final override predicate last(AstNode last, Completion c) {
last(this.getLastChildNode(), last, c)
last(this.getLastStmt(), last, c)
or
not exists(this.getLastChildNode()) and
isValidFor(c, this) and
not exists(this.getLastStmt()) and
c.isValidFor(this) and
last = this
}
override predicate succ(AstNode pred, AstNode succ, Completion c) {
final override predicate succ(AstNode pred, AstNode succ, Completion c) {
pred = this and
first(this.getBodyChild(0, _), succ) and
c instanceof SimpleCompletion
or
StmtSequenceTree.super.succ(pred, succ, c)
}
}
@@ -1213,7 +1205,7 @@ module Trees {
rescuable = true
}
AstNode getLastBodyChild() {
final AstNode getLastBodyChild() {
exists(int i |
result = this.getBodyChild(i, _) and
not exists(this.getBodyChild(i + 1, _))
@@ -1221,16 +1213,6 @@ module Trees {
}
override predicate succ(AstNode pred, AstNode succ, Completion c) {
this instanceof PreOrderTree and
pred = this and
first(this.getBodyChild(0, _), succ) and
c instanceof SimpleCompletion
or
this instanceof PostOrderTree and
succ = this and
last(this.getLastBodyChild(), pred, c) and
c instanceof NormalCompletion
or
// Normal left-to-right evaluation in the body
exists(int i |
last(this.getBodyChild(i, _), pred, c) and
@@ -1240,18 +1222,14 @@ module Trees {
}
}
private class StringConcatenationTree extends StandardPostOrderTree, StringConcatenation {
private class StringConcatenationTree extends StandardTree, StringConcatenation {
final override ControlFlowTree getChildNode(int i) { result = this.getString(i) }
override predicate isHidden() { any() }
}
final override predicate first(AstNode first) { first(this.getFirstChildNode(), first) }
private class StringTextComponentTree extends LeafTree, StringTextComponent {
override predicate isHidden() { any() }
}
private class StringEscapeSequenceComponentTree extends LeafTree, StringEscapeSequenceComponent {
override predicate isHidden() { any() }
final override predicate last(AstNode last, Completion c) {
last(this.getLastChildNode(), last, c)
}
}
private class StringlikeLiteralTree extends StandardPostOrderTree, StringlikeLiteral {
@@ -1264,14 +1242,20 @@ module Trees {
final override ControlFlowTree getChildNode(int i) { result = this.getArgument(i) }
}
private class ToplevelTree extends BodyStmtPreOrderTree, Toplevel {
private class ToplevelTree extends BodyStmtTree, Toplevel {
final override AstNode getBodyChild(int i, boolean rescuable) {
result = this.getBeginBlock(i) and rescuable = true
or
result = BodyStmtPreOrderTree.super.getBodyChild(i - count(this.getABeginBlock()), rescuable)
result = BodyStmtTree.super.getBodyChild(i - count(this.getABeginBlock()), rescuable)
}
override predicate isHidden() { any() }
final override predicate first(AstNode first) { this.firstInner(first) }
final override predicate last(AstNode last, Completion c) { this.lastInner(last, c) }
final override predicate succ(AstNode pred, AstNode succ, Completion c) {
BodyStmtTree.super.succ(pred, succ, c)
}
}
private class TuplePatternTree extends StandardPostOrderTree, TuplePattern {
@@ -1329,13 +1313,6 @@ module Trees {
private class YieldCallTree extends StandardPreOrderTree, YieldCall {
final override ControlFlowTree getChildNode(int i) { result = this.getArgument(i) }
}
/** Gets a child of `n` that is in CFG scope `scope`. */
pragma[noinline]
private AstNode getAChildInScope(AstNode n, CfgScope scope) {
result.getParent() = n and
scope = getCfgScope(result)
}
}
private Scope parent(Scope n) {
@@ -1343,11 +1320,20 @@ private Scope parent(Scope n) {
not n instanceof CfgScope::Range_
}
/** Gets the CFG scope of node `n`. */
pragma[inline]
CfgScope getCfgScope(AstNode n) {
exists(AstNode n0 |
pragma[only_bind_into](n0) = n and
pragma[only_bind_into](result) = getCfgScopeImpl(n0)
)
}
cached
private module Cached {
/** Gets the CFG scope of node `n`. */
cached
CfgScope getCfgScope(AstNode n) {
CfgScope getCfgScopeImpl(AstNode n) {
result = parent*(ASTInternal::fromGenerated(scopeOf(ASTInternal::toGenerated(n))))
}