DataFlow: Cache getSecondLevelScope

[MathiasVP]

I was seeing getSecondLevelScope evaluated 13 times when running security-and-quality on C++:

[2024-04-26 11:45:12] Evaluated non-recursive predicate DataFlowPrivate::getSecondLevelScope/1#14eac193@06c247lf in 6763ms (size: 17958858).
Evaluated relational algebra for predicate DataFlowPrivate::getSecondLevelScope/1#14eac193@06c247lf with tuple counts:
         17974438   ~0%    {2} r1 = SCAN `SSAConstruction::getInstructionAst/1#d0d95b50` OUTPUT In.1, In.0
         17007656   ~2%    {2}    | JOIN WITH `ControlFlowGraph::ControlFlowNode.getEnclosingStmt/0#dispred#fa57cf97` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                       
        171579959   ~0%    {2} r2 = JOIN r1 WITH `boundedFastTC:Stmt::Stmt.getParentStmt/0#dispred#c84c2aca:_ControlFlowGraph::ControlFlowNode.getEnclosingStmt/0#dispred#fa57cf97_SSAConstruction::getInstructi__#higher_order_body` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                       
        188587615   ~0%    {2} r3 = r1 UNION r2
         10692306   ~0%    {2}    | JOIN WITH `DataFlowPrivate::DataFlowSecondLevelScope.getAStmt/0#dispred#a01ddd53_10#join_rhs` ON FIRST 1 OUTPUT Lhs.1, Rhs.1
         18671793  ~17%    {2}    | JOIN WITH `DataFlowPrivate::getAnInstruction/1#db1ad56d_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                           return r3
...
[2024-04-26 11:45:13] Evaluated non-recursive predicate DataFlowPrivate::getSecondLevelScope/1#14eac193@cff7d5oq in 6779ms (size: 17854084).
Evaluated relational algebra for predicate DataFlowPrivate::getSecondLevelScope/1#14eac193@cff7d5oq with tuple counts:
         17974438   ~0%    {2} r1 = SCAN `SSAConstruction::getInstructionAst/1#d0d95b50` OUTPUT In.1, In.0
         17007656   ~2%    {2}    | JOIN WITH `ControlFlowGraph::ControlFlowNode.getEnclosingStmt/0#dispred#fa57cf97` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                       
        171579959   ~0%    {2} r2 = JOIN r1 WITH `boundedFastTC:Stmt::Stmt.getParentStmt/0#dispred#c84c2aca:_ControlFlowGraph::ControlFlowNode.getEnclosingStmt/0#dispred#fa57cf97_SSAConstruction::getInstructi__#higher_order_body` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                       
        188587615   ~0%    {2} r3 = r1 UNION r2
         10692306   ~0%    {2}    | JOIN WITH `DataFlowPrivate::DataFlowSecondLevelScope.getAStmt/0#dispred#a01ddd53_10#join_rhs` ON FIRST 1 OUTPUT Lhs.1, Rhs.1
         18671793  ~17%    {2}    | JOIN WITH `DataFlowPrivate::getAnInstruction/1#db1ad56d_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                           return r3
...
[2024-04-26 11:45:36] Evaluated non-recursive predicate DataFlowPrivate::getSecondLevelScope/1#14eac193@ce798187 in 23420ms (size: 18029768).
Evaluated relational algebra for predicate DataFlowPrivate::getSecondLevelScope/1#14eac193@ce798187 with tuple counts:
         17974438   ~0%    {2} r1 = SCAN `SSAConstruction::getInstructionAst/1#d0d95b50` OUTPUT In.1, In.0
         17007656   ~2%    {2}    | JOIN WITH `ControlFlowGraph::ControlFlowNode.getEnclosingStmt/0#dispred#fa57cf97` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                       
        171579959   ~0%    {2} r2 = JOIN r1 WITH `boundedFastTC:Stmt::Stmt.getParentStmt/0#dispred#c84c2aca:_ControlFlowGraph::ControlFlowNode.getEnclosingStmt/0#dispred#fa57cf97_SSAConstruction::getInstructi__#higher_order_body` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                       
        188587615   ~0%    {2} r3 = r1 UNION r2
         10692306   ~0%    {2}    | JOIN WITH `DataFlowPrivate::DataFlowSecondLevelScope.getAStmt/0#dispred#a01ddd53_10#join_rhs` ON FIRST 1 OUTPUT Lhs.1, Rhs.1
         18671793  ~17%    {2}    | JOIN WITH `DataFlowPrivate::getAnInstruction/1#db1ad56d_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                           return r3

After this PR we just have:

[2024-04-26 13:02:04] Evaluated non-recursive predicate DataFlowImplCommon::Cached::getSecondLevelScopeCached/1#7c22811c@d8fc562i in 33857ms (size: 18161972).
Evaluated relational algebra for predicate DataFlowImplCommon::Cached::getSecondLevelScopeCached/1#7c22811c@d8fc562i with tuple counts:
         17974438   ~0%    {2} r1 = SCAN `SSAConstruction::getInstructionAst/1#d0d95b50` OUTPUT In.1, In.0
         17007656   ~0%    {2}    | JOIN WITH `ControlFlowGraph::ControlFlowNode.getEnclosingStmt/0#dispred#fa57cf97` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                       
        171579959   ~1%    {2} r2 = JOIN r1 WITH `boundedFastTC:Stmt::Stmt.getParentStmt/0#dispred#c84c2aca:_ControlFlowGraph::ControlFlowNode.getEnclosingStmt/0#dispred#fa57cf97_SSAConstruction::getInstructi__#higher_order_body` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                       
        188587615   ~0%    {2} r3 = r1 UNION r2
         10692306   ~0%    {2}    | JOIN WITH `DataFlowPrivate::DataFlowSecondLevelScope.getAStmt/0#dispred#a01ddd53_10#join_rhs` ON FIRST 1 OUTPUT Lhs.1, Rhs.1
         18671793  ~16%    {2}    | JOIN WITH `DataFlowPrivate::getAnInstruction/1#db1ad56d_10#join_rhs` ON FIRST 1 OUTPUT Rhs.1, Lhs.1
                           return r3

[aschackmull]

LGTM

[MathiasVP]

DCA for C/C++ looks fantastic. All other languages are unaffected. I guess C/C++ simply have more second-level scopes than anyone else (which is not surprising, really!) 😅