Store struct member location into the sem.

This CL adds the `@location` of a Struct Member into the
`StructMember` sem object as a `std::optional<uint32_t>`. The
resolver then populates the location value if an attribute is
found during resolution.

This will provide a place to store the evaluated expression value
for a location in the future.

Bug: tint:1633
Change-Id: I6f696968dddf95af1f933d96cdb4a7630badac2e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/101062
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>

src/tint/resolver/inferred_type_test.cc

@@ -149,11 +149,11 @@ TEST_F(ResolverInferredTypeTest, InferStruct_Pass) {
     auto* member = Member("x", ty.i32());
     auto* str = Structure("S", utils::Vector{member});
 
-    auto* expected_type =
-        create<sem::Struct>(str, str->name,
-                            sem::StructMemberList{create<sem::StructMember>(
-                                member, member->symbol, create<sem::I32>(), 0u, 0u, 0u, 4u)},
-                            0u, 4u, 4u);
+    auto* expected_type = create<sem::Struct>(
+        str, str->name,
+        sem::StructMemberList{create<sem::StructMember>(member, member->symbol, create<sem::I32>(),
+                                                        0u, 0u, 0u, 4u, std::nullopt)},
+        0u, 4u, 4u);
 
     auto* ctor_expr = Construct(ty.Of(str));
 

src/tint/resolver/intrinsic_table.cc

@@ -793,7 +793,8 @@ const sem::Struct* build_struct(MatchState& state,
             /* index */ static_cast<uint32_t>(members.size()),
             /* offset */ offset,
             /* align */ align,
-            /* size */ size));
+            /* size */ size,
+            /* location */ std::nullopt));
         offset += size;
     }
     uint32_t size_without_padding = offset;

src/tint/resolver/resolver.cc

@@ -2747,6 +2747,7 @@ sem::Struct* Resolver::Structure(const ast::Struct* str) {
         bool has_offset_attr = false;
         bool has_align_attr = false;
         bool has_size_attr = false;
+        std::optional<uint32_t> location;
         for (auto* attr : member->attributes) {
             Mark(attr);
             if (auto* o = attr->As<ast::StructMemberOffsetAttribute>()) {
@@ -2760,11 +2761,7 @@ sem::Struct* Resolver::Structure(const ast::Struct* str) {
                 align = 1;
                 has_offset_attr = true;
             } else if (auto* a = attr->As<ast::StructMemberAlignAttribute>()) {
-                const auto* expr = Expression(a->align);
-                if (!expr) {
-                    return nullptr;
-                }
-                auto* materialized = Materialize(expr);
+                auto* materialized = Materialize(Expression(a->align));
                 if (!materialized) {
                     return nullptr;
                 }
@@ -2790,6 +2787,8 @@ sem::Struct* Resolver::Structure(const ast::Struct* str) {
                 }
                 size = s->size;
                 has_size_attr = true;
+            } else if (auto* l = attr->As<ast::LocationAttribute>()) {
+                location = l->value;
             }
         }
 
@@ -2811,7 +2810,7 @@ sem::Struct* Resolver::Structure(const ast::Struct* str) {
         auto* sem_member = builder_->create<sem::StructMember>(
             member, member->symbol, type, static_cast<uint32_t>(sem_members.size()),
             static_cast<uint32_t>(offset), static_cast<uint32_t>(align),
-            static_cast<uint32_t>(size));
+            static_cast<uint32_t>(size), location);
         builder_->Sem().Add(member, sem_member);
         sem_members.emplace_back(sem_member);
 

src/tint/resolver/struct_pipeline_stage_use_test.cc

@@ -174,6 +174,20 @@ TEST_F(ResolverPipelineStageUseTest, StructUsedAsShaderParamViaAlias) {
                 UnorderedElementsAre(sem::PipelineStageUsage::kFragmentInput));
 }
 
+TEST_F(ResolverPipelineStageUseTest, StructUsedAsShaderParamLocationSet) {
+    auto* s = Structure("S", utils::Vector{Member("a", ty.f32(), utils::Vector{Location(3)})});
+
+    Func("main", utils::Vector{Param("param", ty.Of(s))}, ty.void_(), utils::Empty,
+         utils::Vector{Stage(ast::PipelineStage::kFragment)});
+
+    ASSERT_TRUE(r()->Resolve()) << r()->error();
+
+    auto* sem = TypeOf(s)->As<sem::Struct>();
+    ASSERT_NE(sem, nullptr);
+    ASSERT_EQ(1u, sem->Members().size());
+    EXPECT_EQ(3u, sem->Members()[0]->Location());
+}
+
 TEST_F(ResolverPipelineStageUseTest, StructUsedAsShaderReturnTypeViaAlias) {
     auto* s = Structure("S", utils::Vector{Member("a", ty.f32(), utils::Vector{Location(0)})});
     auto* s_alias = Alias("S_alias", ty.Of(s));
@@ -190,5 +204,19 @@ TEST_F(ResolverPipelineStageUseTest, StructUsedAsShaderReturnTypeViaAlias) {
                 UnorderedElementsAre(sem::PipelineStageUsage::kFragmentOutput));
 }
 
+TEST_F(ResolverPipelineStageUseTest, StructUsedAsShaderReturnTypeLocationSet) {
+    auto* s = Structure("S", utils::Vector{Member("a", ty.f32(), utils::Vector{Location(3)})});
+
+    Func("main", utils::Empty, ty.Of(s), utils::Vector{Return(Construct(ty.Of(s), Expr(0_f)))},
+         utils::Vector{Stage(ast::PipelineStage::kFragment)});
+
+    ASSERT_TRUE(r()->Resolve()) << r()->error();
+
+    auto* sem = TypeOf(s)->As<sem::Struct>();
+    ASSERT_NE(sem, nullptr);
+    ASSERT_EQ(1u, sem->Members().size());
+    EXPECT_EQ(3u, sem->Members()[0]->Location());
+}
+
 }  // namespace
 }  // namespace tint::resolver

src/tint/sem/sem_struct_test.cc

@@ -105,5 +105,23 @@ TEST_F(StructTest, Layout) {
 /*                               */ };)");
 }
 
+TEST_F(StructTest, Location) {
+    auto* st = Structure("st", utils::Vector{
+                                   Member("a", ty.i32(), utils::Vector{Location(1u)}),
+                                   Member("b", ty.u32()),
+                               });
+
+    auto p = Build();
+    ASSERT_TRUE(p.IsValid()) << p.Diagnostics().str();
+
+    auto* sem = p.Sem().Get(st);
+    ASSERT_EQ(2u, sem->Members().size());
+
+    EXPECT_TRUE(sem->Members()[0]->Location().has_value());
+    EXPECT_EQ(sem->Members()[0]->Location().value(), 1u);
+
+    EXPECT_FALSE(sem->Members()[1]->Location().has_value());
+}
+
 }  // namespace
 }  // namespace tint::sem

src/tint/sem/struct.cc

@@ -161,14 +161,16 @@ StructMember::StructMember(const ast::StructMember* declaration,
                            uint32_t index,
                            uint32_t offset,
                            uint32_t align,
-                           uint32_t size)
+                           uint32_t size,
+                           std::optional<uint32_t> location)
     : declaration_(declaration),
       name_(name),
       type_(type),
       index_(index),
       offset_(offset),
       align_(align),
-      size_(size) {}
+      size_(size),
+      location_(location) {}
 
 StructMember::~StructMember() = default;
 

src/tint/sem/struct.h

@@ -17,6 +17,7 @@
 
 #include <stdint.h>
 
+#include <optional>
 #include <string>
 #include <unordered_set>
 #include <vector>
@@ -180,13 +181,15 @@ class StructMember final : public Castable<StructMember, Node> {
     /// @param offset the byte offset from the base of the structure
     /// @param align the byte alignment of the member
     /// @param size the byte size of the member
+    /// @param location the location attribute, if present
     StructMember(const ast::StructMember* declaration,
                  Symbol name,
                  const sem::Type* type,
                  uint32_t index,
                  uint32_t offset,
                  uint32_t align,
-                 uint32_t size);
+                 uint32_t size,
+                 std::optional<uint32_t> location);
 
     /// Destructor
     ~StructMember() override;
@@ -219,6 +222,9 @@ class StructMember final : public Castable<StructMember, Node> {
     /// @returns byte size
     uint32_t Size() const { return size_; }
 
+    /// @returns the location, if set
+    std::optional<uint32_t> Location() const { return location_; }
+
   private:
     const ast::StructMember* const declaration_;
     const Symbol name_;
@@ -228,6 +234,7 @@ class StructMember final : public Castable<StructMember, Node> {
     const uint32_t offset_;
     const uint32_t align_;
     const uint32_t size_;
+    const std::optional<uint32_t> location_;
 };
 
 }  // namespace tint::sem

src/tint/sem/type_test.cc

@@ -54,7 +54,8 @@ struct TypeTest : public TestHelper {
                                                     /* index */ 0u,
                                                     /* offset */ 0u,
                                                     /* align */ 4u,
-                                                    /* size */ 4u),
+                                                    /* size */ 4u,
+                                                    /* location */ std::nullopt),
                                             },
                                             /* align*/ 4u,
                                             /* size*/ 4u,