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Refactor embedded field calculation to expose access chain

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This allows us to reuse the embedded field calculation in the
logic for generating implicit field selection nodes.
This commit is contained in:
Sauyon Lee
2021-03-10 04:48:59 -08:00
committed by Owen Mansel-Chan
parent c192a255c5
commit e1b4867a19
11 changed files with 107 additions and 42 deletions
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65
ql/src/semmle/go/Types.qll
View File

@@ -375,39 +375,38 @@ class StructType extends @structtype, CompositeType {
this.hasOwnField(_, name, _, isEmbedded)
}
/**
* hasEmbeddedField holds if there is an embedded field at int `depth`, with either type `tp` or `tp`'s pointer type.
*/
private predicate hasEmbeddedField(Type tp, int depth) {
hasFieldOrMethodCand(_, tp, depth, true, false)
or
exists(PointerType embeddedPtr |
hasFieldOrMethodCand(_, embeddedPtr, depth, true, false) and
tp = embeddedPtr.getBaseType()
exists(Field f | this.hasFieldCand(_, f, depth, true) | tp = f.getType().getBaseType*())
}
/**
* getFieldOfEmbedded gets a field of `embeddedParent`, which is then embedded into this struct type.
*/
Field getFieldOfEmbedded(Field embeddedParent, string name, int depth, boolean isEmbedded) {
// embeddedParent is a field of 'this' at depth 'depth - 1'
this.hasFieldCand(_, embeddedParent, depth - 1, true) and
// embeddedParent's type has the result field
exists(StructType embeddedType |
embeddedType = embeddedParent.getType().getBaseType*().getUnderlyingType()
|
result = embeddedType.getOwnField(name, isEmbedded)
)
}
private predicate hasFieldOrMethodCand(
string name, Type tp, int depth, boolean isEmbedded, boolean isMethod
) {
hasOwnField(_, name, tp, isEmbedded) and depth = 0 and isMethod = false
private predicate hasFieldCand(string name, Field f, int depth, boolean isEmbedded) {
f = this.getOwnField(name, isEmbedded) and depth = 0
or
not hasOwnField(_, name, _, _) and
exists(Type embedded | hasEmbeddedField(embedded, depth - 1) |
embedded.getUnderlyingType().(StructType).hasOwnField(_, name, tp, isEmbedded) and
isMethod = false
or
exists(MethodDecl md | md.getReceiverType() = embedded |
name = md.getName() and
tp = md.getType()
) and
isEmbedded = false and
isMethod = true
)
not this.hasOwnField(_, name, _, _) and
f = this.getFieldOfEmbedded(_, name, depth, isEmbedded)
}
private predicate hasFieldOrMethod(string name, Type tp, boolean isMethod) {
exists(int mindepth |
mindepth = min(int depth | hasFieldOrMethodCand(name, _, depth, _, _)) and
hasFieldOrMethodCand(name, tp, mindepth, _, isMethod) and
(strictcount(getFieldCand(name, mindepth, _)) = 1 or isMethod = true)
private predicate hasMethodCand(string name, Method m, int depth) {
name = m.getName() and
exists(Type embedded | this.hasEmbeddedField(embedded, depth - 1) |
m.getReceiverType() = embedded
)
}
@@ -415,7 +414,12 @@ class StructType extends @structtype, CompositeType {
* Holds if this struct contains a field `name` with type `tp`, possibly inside a (nested)
* embedded field.
*/
predicate hasField(string name, Type tp) { hasFieldOrMethod(name, tp, false) }
predicate hasField(string name, Type tp) {
exists(int mindepth |
mindepth = min(int depth | this.hasFieldCand(name, _, depth, _)) and
tp = unique(Field f | f = this.getFieldCand(name, mindepth, _)).getType()
)
}
private Field getFieldCand(string name, int depth, boolean isEmbedded) {
result = this.getOwnField(name, isEmbedded) and depth = 0
@@ -441,7 +445,12 @@ class StructType extends @structtype, CompositeType {
strictcount(getFieldCand(name, depth, _)) = 1
}
override predicate hasMethod(string name, SignatureType tp) { hasFieldOrMethod(name, tp, true) }
override predicate hasMethod(string name, SignatureType tp) {
exists(int mindepth |
mindepth = min(int depth | this.hasMethodCand(name, _, depth)) and
tp = unique(Method m | this.hasMethodCand(name, m, mindepth)).getType()
)
}
language[monotonicAggregates]
override string pp() {

28
ql/src/semmle/go/controlflow/ControlFlowGraphImpl.qll
View File

@@ -48,6 +48,19 @@ private predicate isCond(Expr e) {
e = any(ParenExpr par | isCond(par)).getExpr()
}
private predicate implicitFieldSelection(SelectorExpr e, int i, Field implicitField) {
exists(StructType baseType, Field child |
baseType = e.getBase().getType().getBaseType*().getUnderlyingType() and
(
e.getSelector() = child.getAReference()
or
implicitFieldSelection(e, i + 1, child)
)
|
child = baseType.getFieldOfEmbedded(implicitField, _, i, _)
)
}
/**
* A node in the intra-procedural control-flow graph of a Go function or file.
*
@@ -309,20 +322,7 @@ newtype TControlFlowNode =
* represents an implicit dereference of it.
*/
MkImplicitFieldSelection(SelectorExpr e, int i, Field implicitField) {
exists(Type baseType, StructType baseStructType, Field eField, int minDepth |
eField.getAReference() = e.getSelector() and
baseType = e.getBase().getType().getUnderlyingType() and
baseStructType = [baseType, baseType.(PointerType).getBaseType().getUnderlyingType()] and
baseStructType.getFieldAtDepth(_, minDepth) = eField
|
baseStructType.getFieldAtDepth(_, i) = implicitField and
exists(Type implicitFieldType, StructType implicitFieldStructType |
implicitFieldType = implicitField.getType().getUnderlyingType() and
implicitFieldStructType =
[implicitFieldType, implicitFieldType.(PointerType).getBaseType().getUnderlyingType()] and
implicitFieldStructType.getFieldAtDepth(_, minDepth - i - 1) = eField
)
)
implicitFieldSelection(e, i, implicitField)
} or
/**
* A control-flow node that represents the start of the execution of a function or file.

5
ql/test/library-tests/semmle/go/Types/Field_getPackage.expected
View File

@@ -2,11 +2,16 @@
| cyclic.go:8:3:8:3 | u | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| cyclic.go:9:2:9:2 | f | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| cyclic.go:13:2:13:2 | t | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| cyclic.go:17:2:17:2 | s | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| depth.go:6:2:6:2 | b | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| depth.go:7:2:7:2 | c | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| depth.go:11:2:11:2 | f | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| depth.go:15:2:15:2 | d | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| depth.go:19:2:19:2 | f | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| embedded.go:4:2:4:2 | A | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| embedded.go:8:3:8:5 | Baz | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| embedded.go:13:2:13:4 | Qux | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| embedded.go:14:2:14:4 | Baz | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types |
| pkg1/embedding.go:19:23:19:26 | base | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1 |
| pkg1/embedding.go:22:27:22:30 | base | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1 |
| pkg1/embedding.go:25:24:25:31 | embedder | package github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1 |

6
ql/test/library-tests/semmle/go/Types/Field_hasQualifiedName2.expected
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@@ -5,6 +5,7 @@
| cyclic.go:9:2:9:2 | f | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.u | f |
| cyclic.go:13:2:13:2 | t | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.t | t |
| cyclic.go:13:2:13:2 | t | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.u | t |
| cyclic.go:17:2:17:2 | s | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.v | s |
| depth.go:6:2:6:2 | b | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.a | b |
| depth.go:7:2:7:2 | c | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.a | c |
| depth.go:11:2:11:2 | f | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.a | f |
@@ -13,6 +14,11 @@
| depth.go:15:2:15:2 | d | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.c | d |
| depth.go:19:2:19:2 | f | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.c | f |
| depth.go:19:2:19:2 | f | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.d | f |
| embedded.go:4:2:4:2 | A | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.Baz | A |
| embedded.go:4:2:4:2 | A | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.Qux | A |
| embedded.go:8:3:8:5 | Baz | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.Qux | Baz |
| embedded.go:13:2:13:4 | Qux | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.EmbedsBaz | Qux |
| embedded.go:14:2:14:4 | Baz | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.EmbedsBaz | Baz |
| pkg1/embedding.go:19:23:19:26 | base | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.embedder | base |
| pkg1/embedding.go:19:23:19:26 | base | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.embedder2 | base |
| pkg1/embedding.go:19:23:19:26 | base | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.embedder3 | base |

6
ql/test/library-tests/semmle/go/Types/Field_hasQualifiedName3.expected
View File

@@ -5,6 +5,7 @@
| cyclic.go:9:2:9:2 | f | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | u | f |
| cyclic.go:13:2:13:2 | t | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | t | t |
| cyclic.go:13:2:13:2 | t | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | u | t |
| cyclic.go:17:2:17:2 | s | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | v | s |
| depth.go:6:2:6:2 | b | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | a | b |
| depth.go:7:2:7:2 | c | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | a | c |
| depth.go:11:2:11:2 | f | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | a | f |
@@ -13,6 +14,11 @@
| depth.go:15:2:15:2 | d | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | c | d |
| depth.go:19:2:19:2 | f | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | c | f |
| depth.go:19:2:19:2 | f | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | d | f |
| embedded.go:4:2:4:2 | A | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | Baz | A |
| embedded.go:4:2:4:2 | A | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | Qux | A |
| embedded.go:8:3:8:5 | Baz | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | Qux | Baz |
| embedded.go:13:2:13:4 | Qux | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | EmbedsBaz | Qux |
| embedded.go:14:2:14:4 | Baz | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types | EmbedsBaz | Baz |
| pkg1/embedding.go:19:23:19:26 | base | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1 | embedder | base |
| pkg1/embedding.go:19:23:19:26 | base | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1 | embedder2 | base |
| pkg1/embedding.go:19:23:19:26 | base | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1 | embedder3 | base |

1
ql/test/library-tests/semmle/go/Types/MethodTypes.expected
View File

@@ -16,5 +16,6 @@
| embedder | f | func() int |
| embedder2 | f | func() int |
| embedder3 | f | func() int |
| embedder4 | f | func() int |
| ptrembedder | f | func() int |
| ptrembedder | g | func() int |

4
ql/test/library-tests/semmle/go/Types/QualifiedNames.expected
View File

@@ -5,9 +5,12 @@
| AExtended | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.AExtended |
| B | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.B |
| Bar | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.Bar |
| Baz | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.Baz |
| C | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.C |
| EmbedsBaz | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.EmbedsBaz |
| Foo | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.Foo |
| G | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg2.G |
| Qux | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.Qux |
| T | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.T |
| T | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg2.T |
| T2 | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types/pkg1.T2 |
@@ -26,3 +29,4 @@
| s | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.s |
| t | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.t |
| u | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.u |
| v | github.com/github/codeql-go/ql/test/library-tests/semmle/go/Types.v |

6
ql/test/library-tests/semmle/go/Types/StructFields.expected
View File

@@ -1,8 +1,13 @@
| Bar | pkg1/tst.go:29:10:31:1 | struct type | flag | bool |
| Baz | embedded.go:3:10:5:1 | struct type | A | string |
| EmbedsBaz | embedded.go:12:16:15:1 | struct type | Baz | string |
| EmbedsBaz | embedded.go:12:16:15:1 | struct type | Qux | Qux |
| Foo | pkg1/tst.go:24:10:27:1 | struct type | flag | bool |
| Foo | pkg1/tst.go:24:10:27:1 | struct type | val | int |
| G | pkg2/tst.go:3:8:5:1 | struct type | g | int |
| G | pkg2/tst.go:7:8:9:1 | struct type | g | int |
| Qux | embedded.go:7:10:9:1 | struct type | A | string |
| Qux | embedded.go:7:10:9:1 | struct type | Baz | * Baz |
| T | pkg1/tst.go:3:8:7:1 | struct type | Bar | Bar |
| T | pkg1/tst.go:3:8:7:1 | struct type | Foo | Foo |
| T | pkg1/tst.go:3:8:7:1 | struct type | f | int |
@@ -46,3 +51,4 @@
| u | cyclic.go:12:8:14:1 | struct type | f | int |
| u | cyclic.go:12:8:14:1 | struct type | t | t |
| u | cyclic.go:12:8:14:1 | struct type | u | * u |
| v | cyclic.go:16:8:18:1 | struct type | s | s |

4
ql/test/library-tests/semmle/go/Types/Types.expected
View File

@@ -5,9 +5,12 @@
| AExtended | AExtended |
| B | B |
| Bar | Bar |
| Baz | Baz |
| C | C |
| EmbedsBaz | EmbedsBaz |
| Foo | Foo |
| G | G |
| Qux | Qux |
| T | T |
| T | T |
| T2 | T2 |
@@ -26,3 +29,4 @@
| s | s |
| t | t |
| u | u |
| v | v |

9
ql/test/library-tests/semmle/go/Types/cyclic.go
View File

@@ -12,3 +12,12 @@ type t struct {
type u struct {
t
}
type v struct {
s
}
// the below will cause the test to not terminate
// type w struct {
// v
// }

15
ql/test/library-tests/semmle/go/Types/embedded.go Normal file
View File

@@ -0,0 +1,15 @@
package main
type Baz struct {
A string
}
type Qux struct {
*Baz
}
// EmbedsBaz should have a field A but does not
type EmbedsBaz struct {
Qux
Baz string
}