SymbolTable::New() used to build and return a symbol without a registered name. When you asked for the name of the symbol it would return tint_symbol_N, where N is the numerical identifier for the symbol.
This approach was a major tripping hazzard for transforms that liked to fetch the source program name, and register it in the new program (in this situation, you should always use `CloneContext::Clone(Symbol)`).
Without special casing for unnamed symbols, you could end up promoting the unnamed symbol to a named symbol, and then colliding against a new unnamed symbol.
This is exactly what happened in tint:711.
Instead, with this change:
* The concept of unnamed symbols has been removed. All symbols now have a name.
* The signature of `SymbolTable::New()` has been changed to take a name parameter (which defaults to 'tint_symbol'). This can be used to create a new, unique named symbol (possibly with a suffix), which will not collide with any existing symbols. Note these symbols may still collide if `SymbolTable::Register()` is called with the same name. All Transforms that currently use `SymbolTable::Register()` will be fixed in another change.
* The CloneContext has been updated to use `SymbolTable::New()` instead of `Register()`. This means that any symbols defined before a clone will not collide.
* `CloneContext::CloneSymbols()` has been added which allows a transform to pre-clone all the symbols from the source program. This can be used to avoid the authored identifiers being suffixed with a number, in the case a transform calls New() before the symbol is cloned.
* `Symbol::to_str()` has been changed to return `$<id>` instead of `tint_symbol_N`. This is to avoid any confusion between the actual name and the symbol ID.
Bug: tint:711
Bug: tint:712
Change-Id: I526e4b49b7027545613859de487e6a275686107a
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/47631
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Registering a new Symbol with the NameFor() of the source symbol creates
a new *named* symbol. When mixing these with unnamed symbols we can have
collisions.
Update CloneContext::Clone(Symbol) to properly clone unnamed symbols.
Update (most) the transforms to ctx.Clone() the symbols instead of
registering the names directly.
Fix up the tests where the symbol IDs have changed.
Note: We can still have symbol collisions if a program is authored with
identifiers like 'tint_symbol_3'. This will be fixed up in a later
change.
Change-Id: I0ce559644da3d60e1060f2eef185fa55ae284521
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/46866
Commit-Queue: Ben Clayton <bclayton@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: James Price <jrprice@google.com>
Generates a new unnamed symbol.
Useful for creating temporaries in transforms.
Change-Id: I3aa037e4a6b2d400f24e01bbb3555af68da26748
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/41480
Reviewed-by: dan sinclair <dsinclair@chromium.org>
Commit-Queue: Ben Clayton <bclayton@google.com>
The Symbol suffix is unnecessary, given the class name
Change-Id: Ibf222555a8bf5c3e4b6cf27e8006573570b1bd48
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/38542
Reviewed-by: dan sinclair <dsinclair@chromium.org>
Allows symbols to be used as keys for std::unordered_map and std::unordered_set.
Replace all map / set use of uint32_t for Symbol, where applicable.
Change-Id: If142b4ad1f0ee65bc62209ae2f277e7746be19bb
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/37262
Reviewed-by: dan sinclair <dsinclair@chromium.org>
Commit-Queue: dan sinclair <dsinclair@chromium.org>
This Cl adds a Symbol representing the function name to the function
AST. The symbol is added alongside the name for now. When all usages of
the function name are removed then the string version will be removed
from the constructor.
Change-Id: Ib2450e5fe531e988b25bb7d2937acc6af2187871
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/35220
Commit-Queue: dan sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Auto-Submit: dan sinclair <dsinclair@chromium.org>
This CL adds a table which maps symbols to strings. This will allow us
to remove the use of std::string in the various AST nodes and refer to
the symbols instead.
Change-Id: I902641b3e546a2a44b3b2a39ce4f019cdcbeacc7
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/35100
Commit-Queue: dan sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>
Auto-Submit: dan sinclair <dsinclair@chromium.org>
Ben Clayton
dan sinclair