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C++: Fix performance of leap year queries

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The `sameBaseType` predicate was fundamentally quadratic, and this blew
up on large C++ code bases. Replacing it with calls to `Type.stripType`
fixes performance and does not affect the qltests. It looks like
`sameBaseType` was used purely an ad hoc heuristic, so I'm not worried
about the slight semantic difference between `sameBaseType` and
`stripType`.
This commit is contained in:
Jonas Jensen
2019-07-02 11:17:18 +02:00
parent a0dc84010a
commit 5ad0b39f0c
1 changed files with 2 additions and 22 deletions
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24
cpp/ql/src/semmle/code/cpp/commons/StructLikeClass.qll
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@@ -59,7 +59,7 @@ predicate setter(MemberVariable v, MemberFunction f, Class c) {
v2 != v
) and
f.getNumberOfParameters() = 1 and
sameBaseType(f.getParameter(0).getType(), v.getType())
f.getParameter(0).getType().stripType() = v.getType().stripType()
}
/**
@@ -77,25 +77,5 @@ predicate getter(MemberVariable v, MemberFunction f, Class c) {
v2 != v
) and
f.getNumberOfParameters() = 0 and
sameBaseType(f.getType(), v.getType())
}
/**
* Holds if `t1` and `t2` are the same type up to typedefs, specifiers,
* and removing a single layer of pointers or references (but not arrays).
* Equates, for example, `const int*` with `int`, but not `int**` with `int`
* or `int[]` with `int`.
*/
predicate sameBaseType(Type t1, Type t2) {
exists (Type base1, Type base2 |
base1 = t1.getUnspecifiedType() and
base2 = t2.getUnspecifiedType().getUnspecifiedType() and
(
base1 = base2 or
base1.(PointerType).getBaseType() = base2 or
base2.(PointerType).getBaseType() = base1 or
base1.(ReferenceType).getBaseType() = base2 or
base2.(ReferenceType).getBaseType() = base1
)
)
f.getType().stripType() = v.getType().stripType()
}