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C#: Generalize CFG entry/exit nodes to include field/property initializers
1 parent b28241a commit b7e732f

12 files changed

Lines changed: 119 additions & 60 deletions

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‎csharp/ql/src/semmle/code/csharp/Callable.qll‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -19,7 +19,8 @@ private import semmle.code.csharp.metrics.Complexity
1919
* an anonymous function (`AnonymousFunctionExpr`), or a local function
2020
* (`LocalFunction`).
2121
*/
22-
class Callable extends DotNet::Callable, Parameterizable, ExprOrStmtParent, @callable {
22+
class Callable extends DotNet::Callable, Parameterizable, ExprOrStmtParent, ControlFlowEntryElement,
23+
@callable {
2324
override Type getReturnType() { none() }
2425

2526
/** Gets the annotated return type of this callable. */

‎csharp/ql/src/semmle/code/csharp/Enclosing.qll‎

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -54,30 +54,30 @@ module Internal {
5454
getAChildExpr+(s) = e
5555
}
5656

57-
private predicate childExprOfCallable(Callable parent, Expr child) {
57+
private predicate childExprOfEntryElement(ControlFlowEntryElement parent, Expr child) {
5858
child = getAChildExpr(parent)
5959
or
60-
exists(Expr mid | childExprOfCallable(parent, mid) |
61-
not mid instanceof Callable and
60+
exists(Expr mid | childExprOfEntryElement(parent, mid) |
61+
not mid instanceof ControlFlowEntryElement and
6262
child = getAChildExpr(mid)
6363
)
6464
}
6565

6666
/**
6767
* INTERNAL: Do not use.
6868
*
69-
* Holds if `c` is the enclosing callable of expression `e`.
69+
* Holds if `entry` is the enclosing entry element of expression `e`.
7070
*/
7171
cached
72-
predicate exprEnclosingCallable(Expr e, Callable c) {
72+
predicate exprEnclosingEntryElement(Expr e, ControlFlowEntryElement entry) {
7373
// Compute the enclosing callable of an expression. Note that expressions in
7474
// lambda functions should have the lambdas as enclosing callables, and their
7575
// enclosing statement may be the same as the enclosing statement of the
7676
// lambda; thus, it is *not* safe to go up to the enclosing statement and
7777
// take its own enclosing callable.
78-
childExprOfCallable(c, e)
78+
childExprOfEntryElement(entry, e)
7979
or
80-
not childExprOfCallable(_, e) and
81-
exists(Stmt s | enclosingStmt(e, s) | enclosingCallable(s, c))
80+
not childExprOfEntryElement(_, e) and
81+
exists(Stmt s | enclosingStmt(e, s) | enclosingCallable(s, entry))
8282
}
8383
}

‎csharp/ql/src/semmle/code/csharp/ExprOrStmtParent.qll‎

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -12,7 +12,7 @@ import csharp
1212
* The `expr_parent_top_level()` relation extended to include a relation
1313
* between getters and expression bodies in properties such as `int P => 0`.
1414
*/
15-
predicate expr_parent_top_level_adjusted(Expr child, int i, @top_level_exprorstmt_parent parent) {
15+
predicate expr_parent_top_level_adjusted(Expr child, int i, ControlFlowEntryElement parent) {
1616
expr_parent_top_level(child, i, parent)
1717
or
1818
parent = any(Getter g | expr_parent_top_level(child, i, g.getDeclaration())) and
@@ -108,7 +108,7 @@ class ExprOrStmtParent extends Element, @exprorstmt_parent {
108108
*
109109
* An element that can have a child top-level expression.
110110
*/
111-
class TopLevelExprParent extends Element, @top_level_expr_parent {
111+
class TopLevelExprParent extends ControlFlowEntryElement, @top_level_expr_parent {
112112
final override Expr getChild(int i) { result = this.getChildExpr(i) }
113113

114114
/** Gets the `i`th child expression of this element (zero-based). */

‎csharp/ql/src/semmle/code/csharp/controlflow/BasicBlocks.qll‎

Lines changed: 9 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -74,8 +74,13 @@ class BasicBlock extends TBasicBlockStart {
7474
/** Gets the last control flow node in this basic block. */
7575
ControlFlow::Node getLastNode() { result = getNode(length() - 1) }
7676

77-
/** Gets the callable that this basic block belongs to. */
78-
Callable getCallable() { result = this.getAPredecessor().getCallable() }
77+
/** Gets the callable that this basic block belongs to, if any. */
78+
final Callable getCallable() { result = this.getEntryElement() }
79+
80+
/** Gets the entry element that this basic block belongs to. */
81+
final ControlFlowEntryElement getEntryElement() {
82+
result = this.getFirstNode().getEnclosingElement()
83+
}
7984

8085
/** Gets the length of this basic block. */
8186
int length() { result = strictcount(getANode()) }
@@ -342,12 +347,10 @@ private import Internal
342347

343348
/**
344349
* An entry basic block, that is, a basic block whose first node is
345-
* the entry node of a callable.
350+
* an entry node (`ControlFlow::Nodes::EntryNode`).
346351
*/
347352
class EntryBasicBlock extends BasicBlock {
348353
EntryBasicBlock() { entryBB(this) }
349-
350-
override Callable getCallable() { result.getEntryPoint() = this.getFirstNode() }
351354
}
352355

353356
/** Holds if `bb` is an entry basic block. */
@@ -357,7 +360,7 @@ private predicate entryBB(BasicBlock bb) {
357360

358361
/**
359362
* An exit basic block, that is, a basic block whose last node is
360-
* the exit node of a callable.
363+
* an exit node (`ControlFlow::Nodes::ExitNode`).
361364
*/
362365
class ExitBasicBlock extends BasicBlock {
363366
ExitBasicBlock() { exitBB(this) }

‎csharp/ql/src/semmle/code/csharp/controlflow/ControlFlowElement.qll‎

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -7,6 +7,13 @@ private import ControlFlow::BasicBlocks
77
private import SuccessorTypes
88
private import semmle.code.csharp.Caching
99

10+
/**
11+
* An element that contains a top-level statement or expression. Either a callable
12+
* (`Callable`), an attribute (`Attribute`), a field (`Field`), a property
13+
* (`Property`), an indexer (`Indexer`), or a parameter (`Parameter`).
14+
*/
15+
class ControlFlowEntryElement extends Element, @top_level_exprorstmt_parent { }
16+
1017
/**
1118
* A program element that can possess control flow. That is, either a statement or
1219
* an expression.

‎csharp/ql/src/semmle/code/csharp/controlflow/ControlFlowGraph.qll‎

Lines changed: 59 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -239,38 +239,55 @@ module ControlFlow {
239239
/** Holds if this node has more than one successor. */
240240
predicate isBranch() { strictcount(this.getASuccessor()) > 1 }
241241

242-
/** Gets the enclosing callable of this control flow node. */
242+
/** Gets the enclosing callable of this control flow node, if any. */
243243
Callable getEnclosingCallable() { none() }
244+
245+
/** Gets the enclosing entry element of this control flow node. */
246+
ControlFlowEntryElement getEnclosingElement() { none() }
244247
}
245248

246249
/** Provides different types of control flow nodes. */
247250
module Nodes {
248-
/** A node for a callable entry point. */
251+
private import semmle.code.csharp.Enclosing::Internal
252+
253+
/** An entry node, for example a callable or a field initializer. */
249254
class EntryNode extends Node, TEntryNode {
250-
/** Gets the callable that this entry applies to. */
251-
Callable getCallable() { this = TEntryNode(result) }
255+
private ControlFlowEntryElement e;
256+
257+
EntryNode() { this = TEntryNode(e) }
258+
259+
/** Gets the callable that this entry applies to, if any. */
260+
Callable getCallable() { result = e }
252261

253262
override BasicBlocks::EntryBlock getBasicBlock() { result = Node.super.getBasicBlock() }
254263

255264
override Callable getEnclosingCallable() { result = this.getCallable() }
256265

257-
override Location getLocation() { result = getCallable().getLocation() }
266+
override ControlFlowEntryElement getEnclosingElement() { result = e }
258267

259-
override string toString() { result = "enter " + getCallable().toString() }
268+
override Location getLocation() { result = this.getEnclosingElement().getLocation() }
269+
270+
override string toString() { result = "enter " + this.getEnclosingElement().toString() }
260271
}
261272

262-
/** A node for a callable exit point. */
273+
/** An exit node, for example a callable or a field initializer. */
263274
class ExitNode extends Node, TExitNode {
264-
/** Gets the callable that this exit applies to. */
265-
Callable getCallable() { this = TExitNode(result) }
275+
private ControlFlowEntryElement e;
276+
277+
ExitNode() { this = TExitNode(e) }
278+
279+
/** Gets the callable that this exit applies to, if any. */
280+
Callable getCallable() { result = e }
266281

267282
override BasicBlocks::ExitBlock getBasicBlock() { result = Node.super.getBasicBlock() }
268283

269284
override Callable getEnclosingCallable() { result = this.getCallable() }
270285

271-
override Location getLocation() { result = getCallable().getLocation() }
286+
override ControlFlowEntryElement getEnclosingElement() { result = e }
272287

273-
override string toString() { result = "exit " + getCallable().toString() }
288+
override Location getLocation() { result = this.getEnclosingElement().getLocation() }
289+
290+
override string toString() { result = "exit " + this.getEnclosingElement().toString() }
274291
}
275292

276293
/**
@@ -289,6 +306,10 @@ module ControlFlow {
289306

290307
override Callable getEnclosingCallable() { result = cfe.getEnclosingCallable() }
291308

309+
override ControlFlowEntryElement getEnclosingElement() {
310+
exprEnclosingEntryElement(cfe, result)
311+
}
312+
292313
override ControlFlowElement getElement() { result = cfe }
293314

294315
override string toString() {
@@ -1824,27 +1845,32 @@ module ControlFlow {
18241845
}
18251846

18261847
/**
1827-
* Gets the control flow element that is first executed when entering
1828-
* callable `c`.
1848+
* Gets the control flow element that is first executed when entering `e`.
18291849
*/
1830-
ControlFlowElement succEntry(@top_level_exprorstmt_parent p) {
1831-
p = any(Callable c |
1850+
ControlFlowElement succEntry(ControlFlowEntryElement e) {
1851+
e = any(Callable c |
18321852
if exists(c.(Constructor).getInitializer())
18331853
then result = first(c.(Constructor).getInitializer())
18341854
else result = first(c.getBody())
18351855
)
18361856
or
1837-
expr_parent_top_level_adjusted(any(Expr e | result = first(e)), _, p) and
1838-
not p instanceof Callable
1857+
expr_parent_top_level_adjusted(any(Expr e0 | result = first(e0)), _, e) and
1858+
not e instanceof Callable
18391859
}
18401860

18411861
/**
1842-
* Gets the callable that is exited when `cfe` finishes with completion `c`,
1862+
* Gets the element that is exited when `cfe` finishes with completion `c`,
18431863
* if any.
18441864
*/
1845-
Callable succExit(ControlFlowElement cfe, Completion c) {
1846-
cfe = last(result.getBody(), c) and
1865+
ControlFlowEntryElement succExit(ControlFlowElement cfe, Completion c) {
1866+
cfe = last(result.(Callable).getBody(), c) and
18471867
not c instanceof GotoCompletion
1868+
or
1869+
exists(Expr e |
1870+
expr_parent_top_level_adjusted(e, _, result) and
1871+
cfe = last(e, c) and
1872+
not result instanceof Callable
1873+
)
18481874
}
18491875
}
18501876
import Successor
@@ -1859,13 +1885,13 @@ module ControlFlow {
18591885
*/
18601886
cached
18611887
newtype TNode =
1862-
TEntryNode(Callable c) {
1888+
TEntryNode(ControlFlowEntryElement e) {
18631889
Stages::ControlFlowStage::forceCachingInSameStage() and
1864-
succEntrySplits(c, _, _, _)
1890+
succEntrySplits(e, _, _, _)
18651891
} or
1866-
TExitNode(Callable c) {
1892+
TExitNode(ControlFlowEntryElement e) {
18671893
exists(Reachability::SameSplitsBlock b | b.isReachable(_) |
1868-
succExitSplits(b.getAnElement(), _, c, _)
1894+
succExitSplits(b.getAnElement(), _, e, _)
18691895
)
18701896
} or
18711897
TElementNode(ControlFlowElement cfe, Splits splits) {
@@ -1875,18 +1901,20 @@ module ControlFlow {
18751901
/** Gets a successor node of a given flow type, if any. */
18761902
cached
18771903
Node getASuccessorByType(Node pred, SuccessorType t) {
1878-
// Callable entry node -> callable body
1879-
exists(ControlFlowElement succElement, Splits succSplits |
1880-
result = TElementNode(succElement, succSplits)
1881-
|
1882-
succEntrySplits(pred.(Nodes::EntryNode).getCallable(), succElement, succSplits, t)
1904+
// Entry node -> body
1905+
exists(ControlFlowElement succElement, Splits succSplits, ControlFlowEntryElement e |
1906+
result = TElementNode(succElement, succSplits) and
1907+
pred = TEntryNode(e) and
1908+
succEntrySplits(e, succElement, succSplits, t)
18831909
)
18841910
or
18851911
exists(ControlFlowElement predElement, Splits predSplits |
18861912
pred = TElementNode(predElement, predSplits)
18871913
|
1888-
// Element node -> callable exit
1889-
succExitSplits(predElement, predSplits, result.(Nodes::ExitNode).getCallable(), t)
1914+
// Element node -> exit node
1915+
exists(ControlFlowEntryElement e | result = TExitNode(e) |
1916+
succExitSplits(predElement, predSplits, e, t)
1917+
)
18901918
or
18911919
// Element node -> element node
18921920
exists(ControlFlowElement succElement, Splits succSplits, Completion c |

‎csharp/ql/src/semmle/code/csharp/controlflow/internal/Splitting.qll‎

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -836,7 +836,7 @@ class Splits extends TSplits {
836836
*/
837837
pragma[noinline]
838838
predicate succEntrySplits(
839-
@top_level_exprorstmt_parent pred, ControlFlowElement succ, Splits succSplits, SuccessorType t
839+
ControlFlowEntryElement pred, ControlFlowElement succ, Splits succSplits, SuccessorType t
840840
) {
841841
succ = succEntry(pred) and
842842
t instanceof NormalSuccessor and
@@ -847,7 +847,9 @@ predicate succEntrySplits(
847847
* Holds if `pred` with splits `predSplits` can exit the enclosing callable
848848
* `succ` with type `t`.
849849
*/
850-
predicate succExitSplits(ControlFlowElement pred, Splits predSplits, Callable succ, SuccessorType t) {
850+
predicate succExitSplits(
851+
ControlFlowElement pred, Splits predSplits, ControlFlowEntryElement succ, SuccessorType t
852+
) {
851853
exists(Reachability::SameSplitsBlock b, Completion c | pred = b.getAnElement() |
852854
b.isReachable(predSplits) and
853855
t.matchesCompletion(c) and

‎csharp/ql/src/semmle/code/csharp/exprs/Expr.qll‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -59,7 +59,7 @@ class Expr extends DotNet::Expr, ControlFlowElement, @expr {
5959
final Stmt getEnclosingStmt() { enclosingStmt(this, result) }
6060

6161
/** Gets the enclosing callable of this expression, if any. */
62-
override Callable getEnclosingCallable() { exprEnclosingCallable(this, result) }
62+
override Callable getEnclosingCallable() { exprEnclosingEntryElement(this, result) }
6363

6464
/**
6565
* Holds if this expression is generated by the compiler and does not appear

‎csharp/ql/test/library-tests/controlflow/graph/BasicBlock.expected‎

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -277,11 +277,11 @@
277277
| Foreach.cs:36:10:36:11 | exit M6 | Foreach.cs:36:10:36:11 | exit M6 | 1 |
278278
| Foreach.cs:38:9:39:11 | foreach (... ... in ...) ... | Foreach.cs:38:9:39:11 | foreach (... ... in ...) ... | 1 |
279279
| Foreach.cs:38:26:38:26 | String x | Foreach.cs:39:11:39:11 | ; | 4 |
280-
| Initializers.cs:3:9:3:9 | this access | Initializers.cs:3:9:3:17 | ... = ... | 5 |
281-
| Initializers.cs:4:9:4:9 | this access | Initializers.cs:4:25:4:31 | ... = ... | 6 |
280+
| Initializers.cs:3:9:3:9 | enter F | Initializers.cs:3:9:3:9 | exit F | 7 |
281+
| Initializers.cs:4:9:4:9 | enter G | Initializers.cs:4:9:4:9 | exit G | 8 |
282282
| Initializers.cs:6:5:6:16 | enter Initializers | Initializers.cs:6:5:6:16 | exit Initializers | 3 |
283283
| Initializers.cs:8:10:8:10 | enter M | Initializers.cs:8:10:8:10 | exit M | 20 |
284-
| Initializers.cs:14:20:14:20 | 1 | Initializers.cs:14:16:14:20 | ... = ... | 2 |
284+
| Initializers.cs:14:16:14:16 | enter H | Initializers.cs:14:16:14:16 | exit H | 4 |
285285
| NullCoalescing.cs:3:9:3:10 | enter M1 | NullCoalescing.cs:3:23:3:23 | access to parameter i | 3 |
286286
| NullCoalescing.cs:3:9:3:10 | exit M1 | NullCoalescing.cs:3:9:3:10 | exit M1 | 1 |
287287
| NullCoalescing.cs:3:28:3:28 | 0 | NullCoalescing.cs:3:28:3:28 | 0 | 1 |

‎csharp/ql/test/library-tests/controlflow/graph/BasicBlockDominance.expected‎

Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -564,11 +564,11 @@
564564
| post | Foreach.cs:38:9:39:11 | foreach (... ... in ...) ... | Foreach.cs:38:9:39:11 | foreach (... ... in ...) ... |
565565
| post | Foreach.cs:38:9:39:11 | foreach (... ... in ...) ... | Foreach.cs:38:26:38:26 | String x |
566566
| post | Foreach.cs:38:26:38:26 | String x | Foreach.cs:38:26:38:26 | String x |
567-
| post | Initializers.cs:3:9:3:9 | this access | Initializers.cs:3:9:3:9 | this access |
568-
| post | Initializers.cs:4:9:4:9 | this access | Initializers.cs:4:9:4:9 | this access |
567+
| post | Initializers.cs:3:9:3:9 | enter F | Initializers.cs:3:9:3:9 | enter F |
568+
| post | Initializers.cs:4:9:4:9 | enter G | Initializers.cs:4:9:4:9 | enter G |
569569
| post | Initializers.cs:6:5:6:16 | enter Initializers | Initializers.cs:6:5:6:16 | enter Initializers |
570570
| post | Initializers.cs:8:10:8:10 | enter M | Initializers.cs:8:10:8:10 | enter M |
571-
| post | Initializers.cs:14:20:14:20 | 1 | Initializers.cs:14:20:14:20 | 1 |
571+
| post | Initializers.cs:14:16:14:16 | enter H | Initializers.cs:14:16:14:16 | enter H |
572572
| post | NullCoalescing.cs:3:9:3:10 | enter M1 | NullCoalescing.cs:3:9:3:10 | enter M1 |
573573
| post | NullCoalescing.cs:3:9:3:10 | exit M1 | NullCoalescing.cs:3:9:3:10 | enter M1 |
574574
| post | NullCoalescing.cs:3:9:3:10 | exit M1 | NullCoalescing.cs:3:9:3:10 | exit M1 |
@@ -2111,11 +2111,11 @@
21112111
| pre | Foreach.cs:38:9:39:11 | foreach (... ... in ...) ... | Foreach.cs:38:9:39:11 | foreach (... ... in ...) ... |
21122112
| pre | Foreach.cs:38:9:39:11 | foreach (... ... in ...) ... | Foreach.cs:38:26:38:26 | String x |
21132113
| pre | Foreach.cs:38:26:38:26 | String x | Foreach.cs:38:26:38:26 | String x |
2114-
| pre | Initializers.cs:3:9:3:9 | this access | Initializers.cs:3:9:3:9 | this access |
2115-
| pre | Initializers.cs:4:9:4:9 | this access | Initializers.cs:4:9:4:9 | this access |
2114+
| pre | Initializers.cs:3:9:3:9 | enter F | Initializers.cs:3:9:3:9 | enter F |
2115+
| pre | Initializers.cs:4:9:4:9 | enter G | Initializers.cs:4:9:4:9 | enter G |
21162116
| pre | Initializers.cs:6:5:6:16 | enter Initializers | Initializers.cs:6:5:6:16 | enter Initializers |
21172117
| pre | Initializers.cs:8:10:8:10 | enter M | Initializers.cs:8:10:8:10 | enter M |
2118-
| pre | Initializers.cs:14:20:14:20 | 1 | Initializers.cs:14:20:14:20 | 1 |
2118+
| pre | Initializers.cs:14:16:14:16 | enter H | Initializers.cs:14:16:14:16 | enter H |
21192119
| pre | NullCoalescing.cs:3:9:3:10 | enter M1 | NullCoalescing.cs:3:9:3:10 | enter M1 |
21202120
| pre | NullCoalescing.cs:3:9:3:10 | enter M1 | NullCoalescing.cs:3:9:3:10 | exit M1 |
21212121
| pre | NullCoalescing.cs:3:9:3:10 | enter M1 | NullCoalescing.cs:3:28:3:28 | 0 |

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