[lldb/Plugins] Add ability to fetch crash information on crashed processes

Currently, in macOS, when a process crashes, lldb halts inside the
implementation disassembly without yielding any useful information.
The only way to get more information is to detach from the process, then wait
for ReportCrash to generate a report, find the report, then see what error
message was included in it. Instead of waiting for this to happen, lldb could
locate the error_string and make it available to the user.

This patch addresses this issue by enabling the user to fetch extended
crash information for crashed processes using `process status --verbose`.

Depending on the platform, this will try to gather different crash information
into an structured data dictionnary. This dictionnary is generic and extensible,
as it contains an array for each different type of crash information.

On Darwin Platforms, lldb will iterate over each of the target's images,
extract their `__crash_info` section and generated a StructuredData::Array
containing, in each entry, the module spec, its UUID, the crash messages
and the abort cause. The array will be inserted into the platform's
`m_extended_crash_info` dictionnary and `FetchExtendedCrashInformation` will
return its JSON representation like this:

```
{
  "crash-info annotations": [
    {
      "abort-cause": 0,
      "image": "/usr/lib/system/libsystem_malloc.dylib",
      "message": "main(76483,0x1000cedc0) malloc: *** error for object 0x1003040a0: pointer being freed was not allocated",
      "message2": "",
      "uuid": "5747D0C9-900D-3306-8D70-1E2EA4B7E821"
    },
    ...
  ],
  ...
}
```

This crash information can also be fetched using the SB API or lldb-rpc protocol
using SBTarget::GetExtendedCrashInformation().

rdar://37736535

Differential Revision: https://reviews.llvm.org/D74657

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
12 files changed
tree: 297126371dc3e6cdedbf297b933ca726138d60f2
  1. clang/
  2. clang-tools-extra/
  3. compiler-rt/
  4. debuginfo-tests/
  5. libc/
  6. libclc/
  7. libcxx/
  8. libcxxabi/
  9. libunwind/
  10. lld/
  11. lldb/
  12. llvm/
  13. mlir/
  14. openmp/
  15. parallel-libs/
  16. polly/
  17. pstl/
  18. .arcconfig
  19. .clang-format
  20. .clang-tidy
  21. .git-blame-ignore-revs
  22. .gitignore
  23. CONTRIBUTING.md
  24. README.md
README.md

The LLVM Compiler Infrastructure

This directory and its sub-directories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and run-time environments.

The README briefly describes how to get started with building LLVM. For more information on how to contribute to the LLVM project, please take a look at the Contributing to LLVM guide.

Getting Started with the LLVM System

Taken from https://llvm.org/docs/GettingStarted.html.

Overview

Welcome to the LLVM project!

The LLVM project has multiple components. The core of the project is itself called “LLVM”. This contains all of the tools, libraries, and header files needed to process intermediate representations and converts it into object files. Tools include an assembler, disassembler, bitcode analyzer, and bitcode optimizer. It also contains basic regression tests.

C-like languages use the Clang front end. This component compiles C, C++, Objective C, and Objective C++ code into LLVM bitcode -- and from there into object files, using LLVM.

Other components include: the libc++ C++ standard library, the LLD linker, and more.

Getting the Source Code and Building LLVM

The LLVM Getting Started documentation may be out of date. The Clang Getting Started page might have more accurate information.

This is an example work-flow and configuration to get and build the LLVM source:

  1. Checkout LLVM (including related sub-projects like Clang):

    • git clone https://github.com/llvm/llvm-project.git

    • Or, on windows, git clone --config core.autocrlf=false https://github.com/llvm/llvm-project.git

  2. Configure and build LLVM and Clang:

    • cd llvm-project

    • mkdir build

    • cd build

    • cmake -G <generator> [options] ../llvm

      Some common build system generators are:

      • Ninja --- for generating Ninja build files. Most llvm developers use Ninja.
      • Unix Makefiles --- for generating make-compatible parallel makefiles.
      • Visual Studio --- for generating Visual Studio projects and solutions.
      • Xcode --- for generating Xcode projects.

      Some Common options:

      • -DLLVM_ENABLE_PROJECTS='...' --- semicolon-separated list of the LLVM sub-projects you'd like to additionally build. Can include any of: clang, clang-tools-extra, libcxx, libcxxabi, libunwind, lldb, compiler-rt, lld, polly, or debuginfo-tests.

        For example, to build LLVM, Clang, libcxx, and libcxxabi, use -DLLVM_ENABLE_PROJECTS="clang;libcxx;libcxxabi".

      • -DCMAKE_INSTALL_PREFIX=directory --- Specify for directory the full path name of where you want the LLVM tools and libraries to be installed (default /usr/local).

      • -DCMAKE_BUILD_TYPE=type --- Valid options for type are Debug, Release, RelWithDebInfo, and MinSizeRel. Default is Debug.

      • -DLLVM_ENABLE_ASSERTIONS=On --- Compile with assertion checks enabled (default is Yes for Debug builds, No for all other build types).

    • cmake --build . [-- [options] <target>] or your build system specified above directly.

      • The default target (i.e. ninja or make) will build all of LLVM.

      • The check-all target (i.e. ninja check-all) will run the regression tests to ensure everything is in working order.

      • CMake will generate targets for each tool and library, and most LLVM sub-projects generate their own check-<project> target.

      • Running a serial build will be slow. To improve speed, try running a parallel build. That's done by default in Ninja; for make, use the option -j NNN, where NNN is the number of parallel jobs, e.g. the number of CPUs you have.

    • For more information see CMake

Consult the Getting Started with LLVM page for detailed information on configuring and compiling LLVM. You can visit Directory Layout to learn about the layout of the source code tree.