Commit Graph

11 Commits

Author SHA1 Message Date
Raphael Isemann 00764c36ed [lldb] Add support for evaluating expressions in static member functions
At the moment the expression parser doesn't support evaluating expressions in
static member functions and just pretends the expression is evaluated within a
non-member function. This causes that all static members are inaccessible when
doing unqualified name lookup.

This patch adds support for evaluating in static member functions. It
essentially just does the same setup as what LLDB is already doing for
non-static member functions (i.e., wrapping the expression in a fake member
function) with the difference that we now mark the wrapping function as static
(to prevent access to non-static members).

Reviewed By: shafik, jarin

Differential Revision: https://reviews.llvm.org/D81550
2021-04-22 12:14:31 +02:00
Jonas Devlieghere 38dfb235db [lldb] Support debugging utility functions
LLDB uses utility functions to run code in the inferior for its own
internal purposes, such as reading classes from the Objective-C runtime
for example. Because these expressions should be transparent to the
user, we ignore breakpoints and unwind the stack on errors, which
makes them hard to debug.

This patch adds a new setting target.debug-utility-expression that, when
enabled, changes these options to facilitate debugging. It enables
breakpoints, disables unwinding and writes out the utility function
source code to disk so it shows up in the source view.

Differential revision: https://reviews.llvm.org/D97249
2021-02-24 11:36:01 -08:00
Raphael Isemann 2b37c5b560 [lldb][NFC] Make ClangExpressionSourceCode's wrapping logic more consistent
Summary:
ClangExpressionSourceCode has different ways to wrap the user expression based on
which context the expression is executed in. For example, if we're in a C++ member
function we put the expression inside a fake member function of a fake class to make the
evaluation possible. Similar things are done for Objective-C instance/static methods.
There is also a default wrapping where we put the expression in a normal function
just to make it possible to execute it.

The way we currently define which kind of wrapping the expression needs is based on
the `wrapping_language` we keep passing to the ClangExpressionSourceCode
instance. We repurposed the language type enum for that variable to distinguish the
cases above with the following mapping:
* language = C_plus_plus -> member function wrapping
* language = ObjC -> instance/static method wrapping (`is_static` distinguished between those two).
* language = C -> normal function wrapping
* all other cases like C_plus_plus11, Haskell etc. make our class a no-op that does mostly nothing.

That mapping is currently not documented and just confusing as the `language`
is unrelated to the expression language (and in the ClangUserExpression we even pretend
that it *is* the actual language, but luckily never used it for anything). Some of the code
in ClangExpressionSourceCode is also obviously thinking that this is the actual language of
the expression as it checks for non-existent cases such as `ObjC_plus_plus` which is
not part of the mapping.

This patch makes a new enum to describe the four cases above (with instance/static Objective-C
methods now being their own case). It also make that enum just a member of
ClangExpressionSourceCode instead of having to pass the same value to the class repeatedly.
This gets also rid of all the switch-case-checks for 'unknown' language such as C_plus_plus11 as this
is no longer necessary.

Reviewers: labath, JDevlieghere

Reviewed By: labath

Subscribers: abidh

Differential Revision: https://reviews.llvm.org/D80793
2020-06-01 13:24:30 +02:00
Jonas Devlieghere cdc514e4c6 [lldb] Update header guards to be consistent and compliant with LLVM (NFC)
LLDB has a few different styles of header guards and they're not very
consistent because things get moved around or copy/pasted. This patch
unifies the header guards across LLDB and converts everything to match
LLVM's style.

Differential revision: https://reviews.llvm.org/D74743
2020-02-17 23:15:40 -08:00
Raphael Isemann bd2a910a63 Ignore generated @import statements in the expression evaluator
Summary:
The ClangModulesDeclVendor is currently interpreting all injected `@import` statements in our expression
wrapper as modules that the user has explicitly requested to be persistently loaded. As we inject
`@import` statements with our std module prototype, the ClangModulesDeclVendor will start compiling
and loading unrelated C++ modules because it thinks the user has requested that it should load them. As
the ClangModulesDeclVendor is lacking the setup to compile these modules (e.g. it lacks the include paths),
it will then actually just fail to compile them and cause the whole expression evaluation to fail. This causes
these tests to fail on systems that enable the ClangModulesDeclVendor (such as macOS).

This patch fixes this by preventing the ClangModulesDeclVendor from interpreting `@import` statements
in the wrapper source code. This is done by check if the import happens in the fake source file containing
our wrapper code (which implies it was generated by LLDB).

This patch doesn't reenable the tests as there is more work needed to get the tests running on macOS (D67760)

Reviewers: aprantl, shafik, jingham

Subscribers: lldb-commits

Tags: #c_modules_in_lldb, #lldb

Differential Revision: https://reviews.llvm.org/D61565

llvm-svn: 372690
2019-09-24 06:58:39 +00:00
Raphael Isemann 1442efea9a [lldb] Print better diagnostics for user expressions and modules
Summary:
Currently our expression evaluators only prints very basic errors that are not very useful when writing complex expressions.

For example, in the expression below the user made a type error, but it's not clear from the diagnostic what went wrong:
```
(lldb) expr printf("Modulos are:", foobar%mo1, foobar%mo2, foobar%mo3)
error: invalid operands to binary expression ('int' and 'double')
```

This patch enables full Clang diagnostics in our expression evaluator. After this patch the diagnostics for the expression look like this:

```
(lldb) expr printf("Modulos are:", foobar%mo1, foobar%mo2, foobar%mo3)
error: <user expression 1>:1:54: invalid operands to binary expression ('int' and 'float')
printf("Modulos are:", foobar%mo1, foobar%mo2, foobar%mo3)
                                               ~~~~~~^~~~
```

To make this possible, we now emulate a user expression file within our diagnostics. This prevents that the user is exposed to
our internal wrapper code we inject.

Note that the diagnostics that refer to declarations from the debug information (e.g. 'note' diagnostics pointing to a called function)
will not be improved by this as they don't have any source locations associated with them, so caret or line printing isn't possible.
We instead just suppress these diagnostics as we already do with warnings as they would otherwise just be a context message
without any context (and the original diagnostic in the user expression should be enough to explain the issue).

Fixes rdar://24306342

Reviewers: JDevlieghere, aprantl, shafik, #lldb

Reviewed By: JDevlieghere, #lldb

Subscribers: usaxena95, davide, jingham, aprantl, arphaman, kadircet, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D65646

llvm-svn: 372203
2019-09-18 08:53:35 +00:00
Raphael Isemann 4c7b28d6bb [lldb][NFC] Minor refactorings to (Clang)ExpressionSourceCode
llvm-svn: 368082
2019-08-06 20:25:02 +00:00
Raphael Isemann 08f81513e9 [lldb][NFC] Remove unimplemented ClangExpressionSourceCode::GetNumBodyLines
llvm-svn: 367830
2019-08-05 11:08:47 +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 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