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C++: Add PointerToFieldLiteral class
Marking these expressions as constants fixes the CFG discrepancies that can be observed on the affected test and on snapshots of MySQL.
1 parent bd59029 commit ee16b23

3 files changed

Lines changed: 23 additions & 28 deletions

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‎cpp/ql/src/semmle/code/cpp/exprs/Access.qll‎

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@@ -226,6 +226,29 @@ class ImplicitThisFieldAccess extends FieldAccess {
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ImplicitThisFieldAccess() { not exists(this.getQualifier()) }
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}
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/**
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* A C++ _pointer to non-static data member_ literal. For example, `&C::x` is
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* an expression that refers to field `x` of class `C`. If the type of that
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* field is `int`, then `&C::x` ought to have type `int C::*`. It is currently
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* modeled in QL as having type `int`.
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*
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* See [dcl.mptr] in the C++17 standard or see
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* https://en.cppreference.com/w/cpp/language/pointer#Pointers_to_data_members.
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*/
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class PointerToFieldLiteral extends ImplicitThisFieldAccess {
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PointerToFieldLiteral() {
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// The extractor currently emits a pointer-to-field literal as a field
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// access without a qualifier. The only other unqualified field accesses it
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// emits are for compiler-generated constructors and destructors. When we
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// filter those out, there are only pointer-to-field literals left.
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not this.isCompilerGenerated()
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}
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override predicate isConstant() { any() }
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override string getCanonicalQLClass() { result = "PointerToFieldLiteral" }
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}
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/**
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* A C/C++ function access expression.
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*/

‎cpp/ql/test/library-tests/syntax-zoo/drawDifferent.expected‎

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@@ -1,26 +1,3 @@
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| pointer_to_member__pmIsConst_extractor | false | 15698 | 15698 | pmIsConst |
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| pointer_to_member__pmIsConst_extractor | false | 15724 | 15724 | declaration |
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| pointer_to_member__pmIsConst_extractor | false | 15726 | 15726 | return ... |
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| pointer_to_member__pmIsConst_extractor | false | 15728 | 15728 | { ... } |
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| pointer_to_member__pmIsConst_extractor | false | 15731 | 15731 | {...} |
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| pointer_to_member__pmIsConst_extractor | false | 15734 | 15734 | x1 |
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| pointer_to_member__pmIsConst_extractor | false | 15735 | 15735 | initializer for pms |
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| pointer_to_member__pmIsConst_extractor | true | 15724 | 15726 | |
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| pointer_to_member__pmIsConst_extractor | true | 15726 | 15698 | |
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| pointer_to_member__pmIsConst_extractor | true | 15728 | 15724 | |
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| pointer_to_member__pmIsConst_ql | false | 15698 | 15698 | pmIsConst |
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| pointer_to_member__pmIsConst_ql | false | 15724 | 15724 | declaration |
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| pointer_to_member__pmIsConst_ql | false | 15726 | 15726 | return ... |
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| pointer_to_member__pmIsConst_ql | false | 15728 | 15728 | { ... } |
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| pointer_to_member__pmIsConst_ql | false | 15731 | 15731 | {...} |
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| pointer_to_member__pmIsConst_ql | false | 15734 | 15734 | x1 |
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| pointer_to_member__pmIsConst_ql | false | 15735 | 15735 | initializer for pms |
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| pointer_to_member__pmIsConst_ql | true | 15724 | 15735 | |
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| pointer_to_member__pmIsConst_ql | true | 15726 | 15698 | |
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| pointer_to_member__pmIsConst_ql | true | 15728 | 15724 | |
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| pointer_to_member__pmIsConst_ql | true | 15731 | 15726 | |
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| pointer_to_member__pmIsConst_ql | true | 15734 | 15731 | |
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| pointer_to_member__pmIsConst_ql | true | 15735 | 15734 | |
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| staticlocals__staticlocals_f2_extractor | false | 22465 | 22465 | f2 |
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| staticlocals__staticlocals_f2_extractor | false | 22470 | 22470 | declaration |
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| staticlocals__staticlocals_f2_extractor | false | 22472 | 22472 | declaration |

‎cpp/ql/test/library-tests/syntax-zoo/tellDifferent.expected‎

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Original file line numberDiff line numberDiff line change
@@ -1,8 +1,3 @@
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| pointer_to_member__pmIsConst | pointer_to_member.cpp:33:3:35:22 | declaration | pointer_to_member.cpp:35:11:35:21 | initializer for pms | Standard edge, only from QL |
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| pointer_to_member__pmIsConst | pointer_to_member.cpp:33:3:35:22 | declaration | pointer_to_member.cpp:36:1:36:1 | return ... | Standard edge, only from extractor |
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| pointer_to_member__pmIsConst | pointer_to_member.cpp:35:11:35:21 | initializer for pms | pointer_to_member.cpp:35:13:35:19 | x1 | Standard edge, only from QL |
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| pointer_to_member__pmIsConst | pointer_to_member.cpp:35:11:35:21 | {...} | pointer_to_member.cpp:36:1:36:1 | return ... | Standard edge, only from QL |
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| pointer_to_member__pmIsConst | pointer_to_member.cpp:35:13:35:19 | x1 | pointer_to_member.cpp:35:11:35:21 | {...} | Standard edge, only from QL |
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| staticlocals__staticlocals_f2 | file://:0:0:0:0 | call to C | staticlocals.cpp:30:1:30:1 | return ... | Standard edge, only from QL |
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| staticlocals__staticlocals_f2 | file://:0:0:0:0 | initializer for c | file://:0:0:0:0 | call to C | Standard edge, only from QL |
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| staticlocals__staticlocals_f2 | staticlocals.cpp:29:5:29:17 | declaration | file://:0:0:0:0 | initializer for c | Standard edge, only from QL |

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