5ee67ee6bc
- Use StringRef instead of std::string for `InstructionMemo::Name`.
- Use range for loops, zip_equal and structured bindings in loops.
- Use llvm::any_of instead of manual loops.
- Use ListSeparator.
- Remove {} around single-line if-else chains.
- Use ArrayRef<> instead of const vector reference for function args.
- Change `getLegalCName` to accept a `StringRef` to avoid
StringRef->std::string casting in several places.
- Use StringRef instead of std::string for `OpcodeName` (and in
associated maps).
Tested by verifying no changes in .inc files with and without this
change.
LLVM TableGen
The purpose of TableGen is to generate complex output files based on information from source files that are significantly easier to code than the output files would be, and also easier to maintain and modify over time.
The information is coded in a declarative style involving classes and records, which are then processed by TableGen.
class Hello <string _msg> {
string msg = !strconcat("Hello ", _msg);
}
def HelloWorld: Hello<"world!"> {}
------------- Classes -----------------
class Hello<string Hello:_msg = ?> {
string msg = !strconcat("Hello ", Hello:_msg);
}
------------- Defs -----------------
def HelloWorld { // Hello
string msg = "Hello world!";
}
Try this example on Compiler Explorer.
The internalized records are passed on to various backends, which extract information from a subset of the records and generate one or more output files.
These output files are typically .inc files for C++, but may be any type of file that the backend developer needs.
Resources for learning the language:
- TableGen Overview
- Programmer's reference guide
- Tutorial
- Tools for Learning LLVM TableGen
- Lessons in TableGen (video), slides
- Improving Your TableGen Descriptions (video), slides
Writing TableGen backends:
- TableGen Backend Developer's Guide
- How to write a TableGen backend (video), slides, also available as a notebook.
TableGen in MLIR:
Useful tools: