Commit Graph

8 Commits

Author SHA1 Message Date
Raphael Isemann e21fc8770c Add offsetof support to expression evaluator.
Summary:
We currently don't support offsetof in the expression evaluator as it is implemented as a macro
(which then calls __builtin_offsetof) in stddef.h. The best solution would be to include that
header (or even better, import Clang's builtin module), but header-parsing and
(cross-platform) importing modules is not ready yet.

Until we get this working with modules I would say we add the macro to our existing macro list
as we already do with other macros from stddef.h/stdint.h. We should be able to drop all of them
once we can import the relevant modules by default.

rdar://26040641

Reviewers: shafik, davide

Reviewed By: davide

Subscribers: clayborg, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D64917

llvm-svn: 366476
2019-07-18 17:58:04 +00:00
Raphael Isemann 0171866672 [lldb] Fix handling of dollar characters in expr command
llvm-svn: 365698
2019-07-10 21:04:01 +00:00
Raphael Isemann 090a5b29b8 Fixed some minor style issues in rLLDB359921 [NFC]
Ran clang-format on the added test file and use the new StringRef
comparison over the temporary ConstStrings. Also aligned the
end of one of the code string literals.

llvm-svn: 359931
2019-05-03 21:01:45 +00:00
Shafik Yaghmour e5cbe78259 Fix for ambiguous lookup in expressions between local variable and namespace
Summary:
In an Objective-C context a local variable and namespace can cause an ambiguous name lookup when used in an expression. The solution involves mimicking the existing C++ solution which is to add local using declarations for local variables. This causes a different type of lookup to be used which eliminates the namespace during acceptable results filtering.

Differential Revision: https://reviews.llvm.org/D59960

llvm-svn: 359921
2019-05-03 19:59:22 +00:00
Raphael Isemann 71569d0d52 Inject only relevant local variables in the expression evaluation context
Summary:
In r259902, LLDB started injecting all the locals in every expression
evaluation. This fixed a bunch of issues, but also caused others, mostly
performance regressions on some codebases. The regressions were bad
enough that we added a setting in r274783 to control the behavior and
we have been shipping with the setting off to avoid the perf regressions.

This patch changes the logic injecting the local variables to only inject
the ones present in the expression typed by the user. The approach is
fairly simple and just scans the typed expression for every local name.
Hopefully this gives us the best of both world as it just realizes the
types of the variables really used by the expression.

Landing this requires the 2 other issues I pointed out today to be addressed
but I wanted to gather comments right away.

Original patch by Frédéric Riss!

Reviewers: jingham, clayborg, friss, shafik

Reviewed By: jingham, clayborg

Subscribers: teemperor, labath, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D46551

llvm-svn: 359773
2019-05-02 10:12:56 +00:00
Raphael Isemann 05cfdb0eac Allow direct comparison of ConstString against StringRef
Summary:
When we want to compare a ConstString against a string literal (or any other non-ConstString),
we currently have to explicitly turn the other string into a ConstString. This makes sense as
comparing ConstStrings against each other is only a fast pointer comparison.

However, currently we (rather incorrectly) use in several places in LLDB temporary ConstStrings when
we just want to compare a given ConstString against a hardcoded value, for example like this:
```
if (extension != ConstString(".oat") && extension != ConstString(".odex"))
```

Obviously this kind of defeats the point of ConstStrings. In the comparison above we would
construct two temporary ConstStrings every time we hit the given code. Constructing a
ConstString is relatively expensive: we need to go to the StringPool, take a read and possibly
an exclusive write-lock and then look up our temporary string in the string map of the pool.
So we do a lot of heavy work for essentially just comparing a <6 characters in two strings.

I initially wanted to just fix these issues by turning the temporary ConstString in static variables/
members, but that made the code much less readable. Instead I propose to add a new overload
for the ConstString comparison operator that takes a StringRef. This comparison operator directly
compares the ConstString content against the given StringRef without turning the StringRef into
a ConstString.

This means that the example above can look like this now:
```
if (extension != ".oat" && extension != ".odex")
```
It also no longer has to unlock/lock two locks and call multiple functions in other TUs for constructing
the temporary ConstString instances. Instead this should end up just being a direct string comparison
of the two given strings on most compilers.

This patch also directly updates all uses of temporary and short ConstStrings in LLDB to use this new
comparison operator. It also adds a some unit tests for the new and old comparison operator.

Reviewers: #lldb, JDevlieghere, espindola, amccarth

Reviewed By: JDevlieghere, amccarth

Subscribers: amccarth, clayborg, JDevlieghere, emaste, arichardson, MaskRay, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D60667

llvm-svn: 359281
2019-04-26 07:21:36 +00:00
Raphael Isemann 6c0bbfc0c9 Add ability to import std module into expression parser to improve C++ debugging
Summary:
This patch is the MVP version of importing the std module into the expression parser to improve C++ debugging.

What happens in this patch is that we inject a `@import std` into our expression source code. We also
modify our internal Clang instance for parsing this expression to work with modules and debug info
at the same time (which is the main change in terms of LOC). We implicitly build the `std` module on the first use. The
C++ include paths for building are extracted from the debug info, which means that this currently only
works if the program is compiled with `-glldb -fmodules` and uses the std module. The C include paths
are currently specified by LLDB.

I enabled the tests currently only for libc++ and Linux because I could test this locally. I'll enable the tests
for other platforms once this has landed and doesn't break any bots (and I implemented the platform-specific
C include paths for them).

With this patch we can now:
* Build a libc++ as a module and import it into the expression parser.
* Read from the module while also referencing declarations from the debug info. E.g. `std::abs(local_variable)`.

What doesn't work (yet):
* Merging debug info and C++ module declarations. E.g. `std::vector<CustomClass>` doesn't work.
* Pretty much anything that involves the ASTImporter and templated code. As the ASTImporter is used for saving the result declaration, this means that we can't
call yet any function that returns a non-trivial type.
* Use libstdc++ for this, as it requires multiple include paths and Clang only emits one include path per module. Also libstdc++ doesn't support Clang modules without patches.

Reviewers: aprantl, jingham, shafik, friss, davide, serge-sans-paille

Reviewed By: aprantl

Subscribers: labath, mgorny, abidh, jdoerfert, lldb-commits

Tags: #c_modules_in_lldb, #lldb

Differential Revision: https://reviews.llvm.org/D58125

llvm-svn: 355939
2019-03-12 17:09:33 +00:00
Jim Ingham ea401ec7f4 Factor the clang specific parts of ExpressionSourceCode.{h,cpp} into the clang plugin.
NFC

Differential Revision: https://reviews.llvm.org/D59040

llvm-svn: 355560
2019-03-06 22:43:25 +00:00