From a71bd22de1263cbf5e7774e0abad9653b77cec42 Mon Sep 17 00:00:00 2001
From: Ben Clayton <bclayton@google.com>
Date: Wed, 24 May 2023 23:07:36 +0000
Subject: [PATCH] [tint][constant] Make Value::Clone() return a const pointer

Once constants are de-duplicated, they must be fully immutable.

Bug: tint:1935
Change-Id: Iba1f85079f2ada1f44ba44d1da9b8a65d1abf2ad
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/134361
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: James Price <jrprice@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
---
 src/tint/constant/composite.cc | 2 +-
 src/tint/constant/composite.h  | 2 +-
 src/tint/constant/scalar.h     | 2 +-
 src/tint/constant/splat.cc     | 2 +-
 src/tint/constant/splat.h      | 2 +-
 src/tint/constant/value.h      | 2 +-
 6 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/tint/constant/composite.cc b/src/tint/constant/composite.cc
index 5b004e0998..fee4baf186 100644
--- a/src/tint/constant/composite.cc
+++ b/src/tint/constant/composite.cc
@@ -28,7 +28,7 @@ Composite::Composite(const type::Type* t,
 
 Composite::~Composite() = default;
 
-Composite* Composite::Clone(CloneContext& ctx) const {
+const Composite* Composite::Clone(CloneContext& ctx) const {
     auto* ty = type->Clone(ctx.type_ctx);
     utils::Vector<const constant::Value*, 4> els;
     for (const auto* el : elements) {
diff --git a/src/tint/constant/composite.h b/src/tint/constant/composite.h
index 7a50640d7d..23367a594a 100644
--- a/src/tint/constant/composite.h
+++ b/src/tint/constant/composite.h
@@ -61,7 +61,7 @@ class Composite : public utils::Castable<Composite, Value> {
     /// Clones the constant into the provided context
     /// @param ctx the clone context
     /// @returns the cloned node
-    Composite* Clone(CloneContext& ctx) const override;
+    const Composite* Clone(CloneContext& ctx) const override;
 
     /// The composite type
     type::Type const* const type;
diff --git a/src/tint/constant/scalar.h b/src/tint/constant/scalar.h
index ab5f8528ac..5a40cdf457 100644
--- a/src/tint/constant/scalar.h
+++ b/src/tint/constant/scalar.h
@@ -61,7 +61,7 @@ class Scalar : public utils::Castable<Scalar<T>, Value> {
     /// Clones the constant into the provided context
     /// @param ctx the clone context
     /// @returns the cloned node
-    Scalar* Clone(CloneContext& ctx) const override {
+    const Scalar* Clone(CloneContext& ctx) const override {
         auto* ty = type->Clone(ctx.type_ctx);
         return ctx.dst.constants->Create<Scalar<T>>(ty, value);
     }
diff --git a/src/tint/constant/splat.cc b/src/tint/constant/splat.cc
index 4ebfe5f5f8..e1c9a90fea 100644
--- a/src/tint/constant/splat.cc
+++ b/src/tint/constant/splat.cc
@@ -22,7 +22,7 @@ Splat::Splat(const type::Type* t, const constant::Value* e, size_t n) : type(t),
 
 Splat::~Splat() = default;
 
-Splat* Splat::Clone(CloneContext& ctx) const {
+const Splat* Splat::Clone(CloneContext& ctx) const {
     auto* ty = type->Clone(ctx.type_ctx);
     auto* element = el->Clone(ctx);
     return ctx.dst.constants->Create<Splat>(ty, element, count);
diff --git a/src/tint/constant/splat.h b/src/tint/constant/splat.h
index d8e55a6764..2bf82ddbc5 100644
--- a/src/tint/constant/splat.h
+++ b/src/tint/constant/splat.h
@@ -57,7 +57,7 @@ class Splat : public utils::Castable<Splat, Value> {
     /// Clones the constant into the provided context
     /// @param ctx the clone context
     /// @returns the cloned node
-    Splat* Clone(CloneContext& ctx) const override;
+    const Splat* Clone(CloneContext& ctx) const override;
 
     /// The type of the splat element
     type::Type const* const type;
diff --git a/src/tint/constant/value.h b/src/tint/constant/value.h
index fe1f78a83c..baf1171a3d 100644
--- a/src/tint/constant/value.h
+++ b/src/tint/constant/value.h
@@ -80,7 +80,7 @@ class Value : public utils::Castable<Value, Node> {
     /// Clones the constant into the provided context
     /// @param ctx the clone context
     /// @returns the cloned node
-    virtual Value* Clone(CloneContext& ctx) const = 0;
+    virtual const Value* Clone(CloneContext& ctx) const = 0;
 
   protected:
     /// @returns the value, if this is of a scalar value or abstract numeric, otherwise