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Java/C++: Move range util backEdge predicate to shared pack.

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This commit is contained in:
Anders Schack-Mulligen
2023-11-07 14:03:01 +01:00
parent 8d3ed68b68
commit f2ca52d951
8 changed files with 58 additions and 61 deletions
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3
cpp/ql/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/SemanticCFG.qll
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@@ -12,9 +12,6 @@ class SemBasicBlock extends Specific::BasicBlock {
/** Holds if this block (transitively) dominates `otherblock`. */
final predicate bbDominates(SemBasicBlock otherBlock) { Specific::bbDominates(this, otherBlock) }
/** Holds if this block has dominance information. */
final predicate hasDominanceInformation() { Specific::hasDominanceInformation(this) }
/** Gets an expression that is evaluated in this basic block. */
final SemExpr getAnExpr() { result.getBasicBlock() = this }

2
cpp/ql/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/SemanticExprSpecific.qll
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@@ -199,8 +199,6 @@ module SemanticExprConfig {
dominator.dominates(dominated)
}
predicate hasDominanceInformation(BasicBlock block) { any() }
private predicate id(Cpp::Locatable x, Cpp::Locatable y) { x = y }
private predicate idOf(Cpp::Locatable x, int y) = equivalenceRelation(id/2)(x, y)

33
cpp/ql/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/SemanticSSA.qll
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@@ -63,36 +63,3 @@ class SemSsaReadPositionBlock extends SemSsaReadPosition {
SemExpr getAnExpr() { result = this.getBlock().getAnExpr() }
}
/**
* Holds if `inp` is an input to `phi` along a back edge.
*/
predicate semBackEdge(SemSsaPhiNode phi, SemSsaVariable inp, SemSsaReadPositionPhiInputEdge edge) {
edge.phiInput(phi, inp) and
// Conservatively assume that every edge is a back edge if we don't have dominance information.
(
phi.getBasicBlock().bbDominates(edge.getOrigBlock()) or
irreducibleSccEdge(edge.getOrigBlock(), phi.getBasicBlock()) or
not edge.getOrigBlock().hasDominanceInformation()
)
}
/**
* Holds if the edge from b1 to b2 is part of a multiple-entry cycle in an irreducible control flow
* graph.
*
* An ireducible control flow graph is one where the usual dominance-based back edge detection does
* not work, because there is a cycle with multiple entry points, meaning there are
* mutually-reachable basic blocks where neither dominates the other. For such a graph, we first
* remove all detectable back-edges using the normal condition that the predecessor block is
* dominated by the successor block, then mark all edges in a cycle in the resulting graph as back
* edges.
*/
private predicate irreducibleSccEdge(SemBasicBlock b1, SemBasicBlock b2) {
trimmedEdge(b1, b2) and trimmedEdge+(b2, b1)
}
private predicate trimmedEdge(SemBasicBlock pred, SemBasicBlock succ) {
pred.getASuccessor() = succ and
not succ.bbDominates(pred)
}

4
cpp/ql/lib/semmle/code/cpp/rangeanalysis/new/internal/semantic/analysis/RangeAnalysisImpl.qll
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@@ -72,6 +72,8 @@ module Sem implements Semantic {
class BasicBlock = SemBasicBlock;
BasicBlock getABasicBlockSuccessor(BasicBlock bb) { result = bb.getASuccessor() }
class Guard = SemGuard;
predicate implies_v2 = semImplies_v2/4;
@@ -100,8 +102,6 @@ module Sem implements Semantic {
class SsaReadPositionBlock = SemSsaReadPositionBlock;
predicate backEdge = semBackEdge/3;
predicate conversionCannotOverflow(Type fromType, Type toType) {
SemanticType::conversionCannotOverflow(fromType, toType)
}