The IR construction code wasn't handling lambda expressions, so I added `TranslatedLambdaExpression`. It's pretty straightforward: it creates a temporary variable, initializes it with an `Uninitialized` instruction, then initializes the individual captured fields with the initializer list supplied in the AST.
When testing the case of a lambda with no captures, I noticed that we weren't handling initialization of empty structs with an initializer list correctly, so I fixed that along the way.
I was getting confused by the bad indentation for wrapped lines in
TranslatedInitialization.qll, so I fixed that up in a separate commit.
This commits also adds a test that uses `getParameter`. The new tests
demonstrate that support for array-to-pointer decay works, but we get
data flow to the array rather than its contents.
The configuration in `DefaultOptions.qll` assumed that a call to any
top-level function named `error` would exit the program. This is not
true.
The assumption was probably about `error(3)`, which is a GNU extension.
It only exits if its first argument it not 0. Furthermore, projects such
as openssh may define their own function named `error` with different
behaviour. Because the GNU `error` function is non-standard, it's
perfectly fine to shadow it with a project-specific definition.
This change removes two FPs from `PointlessComparison.qll` on
https://github.com/openssh/openssh-portable.
After a `queries.xml` was added to the test directory,
`Container.getRelativePath` now considers source files to be relative to
the `cpp/test` directory rather than the directory of the `*.ql*` file.
This caused some benign test output changes, and it also caused an
unwanted alert for `test3.c:14` to appear in
`cpp/ql/test/query-tests/Security/CWE/CWE-190/semmle/tainted/IntegerOverflowTainted.expected`.
This alert came about because `inSystemMacroExpansion` holds for files
that don't have a relative path, but the pretend system header in
`../system_header` now does have a relative path because it's below the
`cpp/test` directory. The fix is to add another `queries.xml` just for
the directory with the affected test.
This change fixes a few key problems with the existing SSA implementations:
For unaliased SSA, we were incorrectly choosing to model a local variable that had accesses that did not cover the entire variable. This has been changed to ensure that all accesses to the variable are at offset zero and have the same type as the variable itself. This was only possible to fix now that every `MemoryOperand` has its own type.
For aliased SSA, we now correctly track the offset and size of each memory access using an interval of bit offsets covered by the access. The offset interval makes the overlap computation more straightforward. Again, this is only possible now that operands have types.
The `getXXXMemoryAccess` predicates are now driven by the `MemoryAccessKind` on the operands and results, instead of by specific opcodes.
This change does fix an existing false negative in the IR dataflow tests.
I added a few simple test cases to the SSA IR tests, covering the various kinds of overlap (MustExcactly, MustTotally, and MayPartially).
I added "PrintSSA.qll", which can dump the SSA memory accesses as part of an IR dump.
For function parameters that are subject to "pointer decay", the database contains the type as originally declared (e.g. `T[]` instead of `T*`). The IR needs the actual type. Similarly, for variable declared as an array of unknown size, the actual size needs to be inferred from the initializer (e.g. `char a[] = "blah";` needs to have the type `char[5]`).
I've opened a ticket to have the extractor emit the actual type alongside the declared type, but for now, this workaround is enough to unblock progress for typical code.
The IR tests were getting kind of unwieldy. We were using "ir.cpp" to contain test cases that covered both IR construction (every language construct imaginable) and SSA construction. We would then build and dump all three flavors of IR. For IR construction tests, examining the SSA dumps when you add a new test case is tedious.
To make this easier to manage, I've split the SSA-specific test cases out into a separate directory. "ir.cpp" should now contain only IR construction test cases, and "ssa.cpp" should contain only SSA construction test cases. We dump just the raw IR for "ir.cpp", and just the two SSA flavors for "ssa.cpp". We still run all three flavors of the IR sanity tests for "ir.cpp", though.
I also removed the "ssa_block_count.ql" test, which wasn't really adding any coverage, because any change to the block count would be reflected in the dump as well.
