transforms: Add a ProgramBuilder::Sym() helper

This creates a new, unnamed symbol.

Change-Id: I0ea11e812296c3215ba624a18777d3e7233e2ae4
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/49441
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Auto-Submit: James Price <jrprice@google.com>

src/program_builder.h

@@ -878,6 +878,9 @@ class ProgramBuilder {
   // AST helper methods
   //////////////////////////////////////////////////////////////////////////////
 
+  /// @return a new unnamed symbol
+  Symbol Sym() { return Symbols().New(); }
+
   /// @param name the symbol string
   /// @return a Symbol with the given name
   Symbol Sym(const std::string& name) { return Symbols().Register(name); }

src/transform/calculate_array_length.cc

@@ -80,7 +80,7 @@ Output CalculateArrayLength::Run(const Program* in, const DataMap&) {
   std::unordered_map<sem::StructType*, Symbol> buffer_size_intrinsics;
   auto get_buffer_size_intrinsic = [&](sem::StructType* buffer_type) {
     return utils::GetOrCreate(buffer_size_intrinsics, buffer_type, [&] {
-      auto name = ctx.dst->Symbols().New();
+      auto name = ctx.dst->Sym();
       auto* func = ctx.dst->create<ast::Function>(
           name,
           ast::VariableList{
@@ -183,7 +183,7 @@ Output CalculateArrayLength::Run(const Program* in, const DataMap&) {
                 // Construct the variable that'll hold the result of
                 // RWByteAddressBuffer.GetDimensions()
                 auto* buffer_size_result = ctx.dst->Decl(ctx.dst->Var(
-                    ctx.dst->Symbols().New(), ctx.dst->ty.u32(),
+                    ctx.dst->Sym(), ctx.dst->ty.u32(),
                     ast::StorageClass::kFunction, ctx.dst->Expr(0u)));
 
                 // Call storage_buffer.GetDimensions(buffer_size_result)
@@ -199,7 +199,7 @@ Output CalculateArrayLength::Run(const Program* in, const DataMap&) {
                 //                total_storage_buffer_size - array_offset
                 // array_length = ----------------------------------------
                 //                             array_stride
-                auto name = ctx.dst->Symbols().New();
+                auto name = ctx.dst->Sym();
                 uint32_t array_offset = array_member_sem->Offset();
                 uint32_t array_stride = array_member_sem->Size();
                 auto* array_length_var = ctx.dst->Decl(ctx.dst->Const(

src/transform/canonicalize_entry_point_io.cc

@@ -99,7 +99,7 @@ Output CanonicalizeEntryPointIO::Run(const Program* in, const DataMap&) {
 
     if (!func->params().empty()) {
       // Collect all parameters and build a list of new struct members.
-      auto new_struct_param_symbol = ctx.dst->Symbols().New();
+      auto new_struct_param_symbol = ctx.dst->Sym();
       ast::StructMemberList new_struct_members;
       for (auto* param : func->params()) {
         auto param_name = ctx.Clone(param->symbol());
@@ -175,7 +175,7 @@ Output CanonicalizeEntryPointIO::Run(const Program* in, const DataMap&) {
                 StructMemberComparator);
 
       // Create the new struct type.
-      auto in_struct_name = ctx.dst->Symbols().New();
+      auto in_struct_name = ctx.dst->Sym();
       auto* in_struct =
           ctx.dst->create<sem::StructType>(ctx.dst->create<ast::Struct>(
               in_struct_name, new_struct_members, ast::DecorationList{}));
@@ -221,7 +221,7 @@ Output CanonicalizeEntryPointIO::Run(const Program* in, const DataMap&) {
                 StructMemberComparator);
 
       // Create the new struct type.
-      auto out_struct_name = ctx.dst->Symbols().New();
+      auto out_struct_name = ctx.dst->Sym();
       auto* out_struct =
           ctx.dst->create<sem::StructType>(ctx.dst->create<ast::Struct>(
               out_struct_name, new_struct_members, ast::DecorationList{}));
@@ -242,7 +242,7 @@ Output CanonicalizeEntryPointIO::Run(const Program* in, const DataMap&) {
           if (!ret->value()->Is<ast::IdentifierExpression>()) {
             // Create a const to hold the return value expression to avoid
             // re-evaluating it multiple times.
-            auto temp = ctx.dst->Symbols().New();
+            auto temp = ctx.dst->Sym();
             auto* temp_var = ctx.dst->Decl(
                 ctx.dst->Const(temp, ctx.Clone(ret_type), new_ret_value()));
             ctx.InsertBefore(ret_sem->Block()->statements(), ret, temp_var);

src/transform/decompose_storage_access.cc

@@ -425,7 +425,7 @@ struct State {
       ast::Function* func = nullptr;
       if (auto* intrinsic = IntrinsicLoadFor(ctx.dst, el_ty)) {
         func = ctx.dst->create<ast::Function>(
-            ctx.dst->Symbols().New(), params, ctx.Clone(el_ty), nullptr,
+            ctx.dst->Sym(), params, ctx.Clone(el_ty), nullptr,
             ast::DecorationList{intrinsic}, ast::DecorationList{});
       } else {
         ast::ExpressionList values;
@@ -458,7 +458,7 @@ struct State {
           }
         }
         func = ctx.dst->create<ast::Function>(
-            ctx.dst->Symbols().New(), params, ctx.Clone(el_ty),
+            ctx.dst->Sym(), params, ctx.Clone(el_ty),
             ctx.dst->Block(
                 ctx.dst->Return(ctx.dst->create<ast::TypeConstructorExpression>(
                     ctx.Clone(el_ty), values))),
@@ -489,7 +489,7 @@ struct State {
       ast::Function* func = nullptr;
       if (auto* intrinsic = IntrinsicStoreFor(ctx.dst, el_ty)) {
         func = ctx.dst->create<ast::Function>(
-            ctx.dst->Symbols().New(), params, ctx.dst->ty.void_(), nullptr,
+            ctx.dst->Sym(), params, ctx.dst->ty.void_(), nullptr,
             ast::DecorationList{intrinsic}, ast::DecorationList{});
 
       } else {
@@ -531,8 +531,8 @@ struct State {
           }
         }
         func = ctx.dst->create<ast::Function>(
-            ctx.dst->Symbols().New(), params, ctx.dst->ty.void_(),
+            ctx.dst->Sym(), params, ctx.dst->ty.void_(), ctx.dst->Block(body),
-            ctx.dst->Block(body), ast::DecorationList{}, ast::DecorationList{});
+            ast::DecorationList{}, ast::DecorationList{});
       }
 
       InsertGlobal(ctx, insert_after, func);

src/transform/first_index_offset.cc

@@ -134,11 +134,11 @@ Output FirstIndexOffset::Run(const Program* in, const DataMap& data) {
       offset += 4;
     }
     auto struct_type =
-        ctx.dst->Structure(ctx.dst->Symbols().New(), std::move(members),
+        ctx.dst->Structure(ctx.dst->Sym(), std::move(members),
                            {ctx.dst->create<ast::StructBlockDecoration>()});
 
     // Create a global to hold the uniform buffer
-    Symbol buffer_name = ctx.dst->Symbols().New();
+    Symbol buffer_name = ctx.dst->Sym();
     ctx.dst->Global(buffer_name, struct_type, ast::StorageClass::kUniform,
                     nullptr,
                     ast::DecorationList{

src/transform/hlsl.cc

@@ -98,7 +98,7 @@ void Hlsl::PromoteInitializersToConstVar(CloneContext& ctx) const {
       auto* src_ty = src_sem_expr->Type();
       if (src_ty->IsAnyOf<sem::ArrayType, sem::StructType>()) {
         // Create a new symbol for the constant
-        auto dst_symbol = ctx.dst->Symbols().New();
+        auto dst_symbol = ctx.dst->Sym();
         // Clone the type
         auto* dst_ty = ctx.Clone(src_ty);
         // Clone the initializer

src/transform/renamer.cc

@@ -906,7 +906,7 @@ Output Renamer::Run(const Program* in, const DataMap&) {
         break;
     }
 
-    auto sym_out = ctx.dst->Symbols().New();
+    auto sym_out = ctx.dst->Sym();
     remappings.emplace(name_in, ctx.dst->Symbols().NameFor(sym_out));
     return sym_out;
   });

src/transform/spirv.cc

@@ -154,7 +154,7 @@ void Spirv::HandleEntryPointIOTypes(CloneContext& ctx) const {
 
     if (!func->return_type()->Is<sem::Void>()) {
       ast::StatementList stores;
-      auto store_value_symbol = ctx.dst->Symbols().New();
+      auto store_value_symbol = ctx.dst->Sym();
       HoistToOutputVariables(
           ctx, func, func->return_type(), func->return_type(),
           func->return_type_decorations(), {}, store_value_symbol, stores);
@@ -162,7 +162,7 @@ void Spirv::HandleEntryPointIOTypes(CloneContext& ctx) const {
       // Create a function that writes a return value to all output variables.
       auto* store_value =
           ctx.dst->Param(store_value_symbol, ctx.Clone(func->return_type()));
-      auto return_func_symbol = ctx.dst->Symbols().New();
+      auto return_func_symbol = ctx.dst->Sym();
       auto* return_func = ctx.dst->create<ast::Function>(
           return_func_symbol, ast::VariableList{store_value},
           ctx.dst->ty.void_(), ctx.dst->create<ast::BlockStatement>(stores),
@@ -262,7 +262,7 @@ Symbol Spirv::HoistToInputVariables(
           return !deco->IsAnyOf<ast::BuiltinDecoration,
                                 ast::LocationDecoration>();
         });
-    auto global_var_symbol = ctx.dst->Symbols().New();
+    auto global_var_symbol = ctx.dst->Sym();
     auto* global_var =
         ctx.dst->Var(global_var_symbol, ctx.Clone(declared_ty),
                      ast::StorageClass::kInput, nullptr, new_decorations);
@@ -279,7 +279,7 @@ Symbol Spirv::HoistToInputVariables(
     init_value_names.emplace_back(member_var);
   }
 
-  auto func_var_symbol = ctx.dst->Symbols().New();
+  auto func_var_symbol = ctx.dst->Sym();
   if (func->body()->empty()) {
     // The return value should never get used.
     return func_var_symbol;
@@ -315,7 +315,7 @@ void Spirv::HoistToOutputVariables(CloneContext& ctx,
           return !deco->IsAnyOf<ast::BuiltinDecoration,
                                 ast::LocationDecoration>();
         });
-    auto global_var_symbol = ctx.dst->Symbols().New();
+    auto global_var_symbol = ctx.dst->Sym();
     auto* global_var =
         ctx.dst->Var(global_var_symbol, ctx.Clone(declared_ty),
                      ast::StorageClass::kOutput, nullptr, new_decorations);

src/transform/vertex_pulling.cc

@@ -487,11 +487,10 @@ struct State {
         new_members.push_back(
             ctx.dst->Member(member_sym, member_type, std::move(member_decos)));
       }
-      auto new_struct =
+      auto new_struct = ctx.dst->Structure(ctx.dst->Sym(), new_members);
-          ctx.dst->Structure(ctx.dst->Symbols().New(), new_members);
 
       // Create a new function parameter with this struct.
-      auto* new_param = ctx.dst->Param(ctx.dst->Symbols().New(), new_struct);
+      auto* new_param = ctx.dst->Param(ctx.dst->Sym(), new_struct);
       new_function_parameters.push_back(new_param);
 
       // Copy values from the new parameter to the function-scope variable.