diff options
| author | Tim Foley <tfoley@nvidia.com> | 2017-08-09 12:57:37 -0700 |
|---|---|---|
| committer | Tim Foley <tfoley@nvidia.com> | 2017-08-10 13:05:04 -0700 |
| commit | a5a436c4783fb75a0d089a6483219c06db91f593 (patch) | |
| tree | 224c16ad374c5ed533a497beeb75753e7ce2d771 /source/slang/preprocessor.h | |
| parent | 6e4830f4d74adef0a47c6503d84dc114240fafa3 (diff) | |
Make source location lightweight
Fixes #24
So far the code has used a representation for source locations that is heavy-weight, but typical of research or hobby compilers: a `struct` type containing a line number and a (heap-allocated) string.
This is actually very convenient for debugging, but it means that any data structure that might contain a source location needs careful memory management (because of those strings) and has a tendency to bloat.
The new represnetation is that a source location is just a pointer-sized integer.
In the simplest mental model, you can think of this as just counting every byte of source text that is passed in, and using those to name locations.
Finding the path and line number that corresponds to a location involves a lookup step, but we can arrange to store all the files in an array sorted by their start locations, and do a binary search.
Finding line numbers inside a file is similarly fast (one you pay a one-time cost to build an array of starting offsets for lines).
More advanced compilers like clang actually go further and create a unique range of source locations to represent a file each time it gets included, so that they can track the include stack and reproduce it in diagnostic messages.
I'm not doing anything that clever here.
Diffstat (limited to 'source/slang/preprocessor.h')
| -rw-r--r-- | source/slang/preprocessor.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/source/slang/preprocessor.h b/source/slang/preprocessor.h index 008707ffb..64591ef03 100644 --- a/source/slang/preprocessor.h +++ b/source/slang/preprocessor.h @@ -31,8 +31,7 @@ struct IncludeHandler // Take a string of source code and preprocess it into a list of tokens. TokenList preprocessSource( - String const& source, - String const& fileName, + SourceFile* file, DiagnosticSink* sink, IncludeHandler* includeHandler, Dictionary<String, String> defines, |