6e3071007b
Introduce `MacroExpansionContext` to track what and how macros in a translation
unit expand. This is the first element of the patch-stack in this direction.
The main goal is to substitute the current macro expansion generator in the
`PlistsDiagnostics`, but all the other `DiagnosticsConsumer` could benefit from
this.
`getExpandedText` and `getOriginalText` are the primary functions of this class.
The former can provide you the text that was the result of the macro expansion
chain starting from a `SourceLocation`.
While the latter will tell you **what text** was in the original source code
replaced by the macro expansion chain from that location.
Here is an example:
void bar();
#define retArg(x) x
#define retArgUnclosed retArg(bar()
#define BB CC
#define applyInt BB(int)
#define CC(x) retArgUnclosed
void unbalancedMacros() {
applyInt );
//^~~~~~~~~~^ is the substituted range
// Original text is "applyInt )"
// Expanded text is "bar()"
}
#define expandArgUnclosedCommaExpr(x) (x, bar(), 1
#define f expandArgUnclosedCommaExpr
void unbalancedMacros2() {
int x = f(f(1)) )); // Look at the parenthesis!
// ^~~~~~^ is the substituted range
// Original text is "f(f(1))"
// Expanded text is "((1,bar(),1,bar(),1"
}
Might worth investigating how to provide a reusable component, which could be
used for example by a standalone tool eg. expanding all macros to their
definitions.
I borrowed the main idea from the `PrintPreprocessedOutput.cpp` Frontend
component, providing a `PPCallbacks` instance hooking the preprocessor events.
I'm using that for calculating the source range where tokens will be expanded
to. I'm also using the `Preprocessor`'s `OnToken` callback, via the
`Preprocessor::setTokenWatcher` to reconstruct the expanded text.
Unfortunately, I concatenate the token's string representation without any
whitespaces except if the token is an identifier when I emit an extra space
to produce valid code for `int var` token sequences.
This could be improved later if needed.
Patch-stack:
1) D93222 (this one) Introduces the MacroExpansionContext class and unittests
2) D93223 Create MacroExpansionContext member in AnalysisConsumer and pass
down to the diagnostics consumers
3) D93224 Use the MacroExpansionContext for macro expansions in plists
It replaces the 'old' macro expansion mechanism.
4) D94673 API for CTU macro expansions
You should be able to get a `MacroExpansionContext` for each imported TU.
Right now it will just return `llvm::None` as this is not implemented yet.
5) FIXME: Implement macro expansion tracking for imported TUs as well.
It would also relieve us from bugs like:
- [fixed] D86135
- [confirmed] The `__VA_ARGS__` and other macro nitty-gritty, such as how to
stringify macro parameters, where to put or swallow commas, etc. are not
handled correctly.
- [confirmed] Unbalanced parenthesis are not well handled - resulting in
incorrect expansions or even crashes.
- [confirmed][crashing] https://bugs.llvm.org/show_bug.cgi?id=48358
Reviewed By: martong, Szelethus
Differential Revision: https://reviews.llvm.org/D93222
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| .github | ||
| clang | ||
| clang-tools-extra | ||
| compiler-rt | ||
| debuginfo-tests | ||
| flang | ||
| libc | ||
| libclc | ||
| libcxx | ||
| libcxxabi | ||
| libunwind | ||
| lld | ||
| lldb | ||
| llvm | ||
| mlir | ||
| openmp | ||
| parallel-libs | ||
| polly | ||
| pstl | ||
| runtimes | ||
| utils/arcanist | ||
| .arcconfig | ||
| .arclint | ||
| .clang-format | ||
| .clang-tidy | ||
| .git-blame-ignore-revs | ||
| .gitignore | ||
| CONTRIBUTING.md | ||
| 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:
-
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
-
-
Configure and build LLVM and Clang:
-
cd llvm-project -
cmake -S llvm -B build -G <generator> [options]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 build [-- [options] <target>]or your build system specified above directly.-
The default target (i.e.
ninjaormake) will build all of LLVM. -
The
check-alltarget (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, whereNNNis 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.