commit 4a92a3c904d6a4ce477b077281ce178305f551c1
author Ben Clayton <bclayton@google.com> Mon Jul 18 20:50:02 2022 +0000
committer Dawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Jul 18 20:50:02 2022 +0000
tree 44d4c0be2f51eb2e345c65394f4d3047761f77c3
parent 8d73198aca5f1a83283068298c9bfd79640ca36b

tint: Optimize sem node lookup

Add a 'NodeID' to each ast::Node which is the sequentially allocated
index of the node. Use this in sem::Info to map the AST node to the
semantic node, instead of using a std::unordered_map.

Optimised very hot code by entirely eliminating map lookups, and
dramatically reducing cache misses (lookups are usually sequentually
ordered).

Timings running
'webgpu:shader,execution,expression,call,builtin,atan2:f32:inputSource="const";vectorize="_undef_"'
with dawn/node, using SwiftShader:

    Without change: 3.22647107s
    With change:    3.10578879s

Bug: tint:1613
Change-Id: I22ec48d933b2e5f9da04494bff4e979e6f7b1982
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/96140
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>

src/tint/ast/statement.h

diff --git a/src/tint/ast/statement.h b/src/tint/ast/statement.h
index 94de247..e3a96d1 100644
--- a/src/tint/ast/statement.h
+++ b/src/tint/ast/statement.h
@@ -32,8 +32,9 @@
   protected:
     /// Constructor
     /// @param pid the identifier of the program that owns this node
+    /// @param nid the unique node identifier
     /// @param src the source of the expression
-    Statement(ProgramID pid, const Source& src);
+    Statement(ProgramID pid, NodeID nid, const Source& src);
     /// Move constructor
     Statement(Statement&&);
 };