Make more SymbolTable methods string_view.

This CL updates more of the SymbolTable to use string views.

Change-Id: I0d9c7817ba4e3b0d0e73cfc02406481eb796c3c2
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/127320
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Ben Clayton <bclayton@google.com>

src/tint/symbol.cc

@@ -52,6 +52,10 @@ std::string Symbol::to_str() const {
     return "$" + std::to_string(val_);
 }
 
+std::string_view Symbol::NameView() const {
+    return name_;
+}
+
 std::string Symbol::Name() const {
     return std::string(name_);
 }

src/tint/symbol.h

@@ -76,6 +76,10 @@ class Symbol {
     /// @return the string representation of the symbol
     std::string to_str() const;
 
+    /// Converts the symbol to the registered name
+    /// @returns the string_view representing the name of the symbol
+    std::string_view NameView() const;
+
     /// Converts the symbol to the registered name
     /// @returns the string representing the name of the symbol
     std::string Name() const;

src/tint/symbol_table.cc

@@ -26,14 +26,17 @@ SymbolTable::~SymbolTable() = default;
 
 SymbolTable& SymbolTable::operator=(SymbolTable&&) = default;
 
-Symbol SymbolTable::Register(const std::string& name) {
+Symbol SymbolTable::Register(std::string_view name) {
     TINT_ASSERT(Symbol, !name.empty());
 
     auto it = name_to_symbol_.Find(name);
     if (it) {
         return *it;
     }
+    return RegisterInternal(name);
+}
 
+Symbol SymbolTable::RegisterInternal(std::string_view name) {
     char* name_mem = name_allocator_.Allocate(name.length() + 1);
     if (name_mem == nullptr) {
         return Symbol();
@@ -43,26 +46,28 @@ Symbol SymbolTable::Register(const std::string& name) {
     std::string_view nv(name_mem, name.length());
 
     Symbol sym(next_symbol_, program_id_, nv);
-
     ++next_symbol_;
-
-    name_to_symbol_.Add(name_mem, sym);
+    name_to_symbol_.Add(sym.NameView(), sym);
 
     return sym;
 }
 
-Symbol SymbolTable::Get(const std::string& name) const {
+Symbol SymbolTable::Get(std::string_view name) const {
     auto it = name_to_symbol_.Find(name);
     return it ? *it : Symbol();
 }
 
-Symbol SymbolTable::New(std::string prefix /* = "" */) {
-    if (prefix.empty()) {
+Symbol SymbolTable::New(std::string_view prefix_view /* = "" */) {
+    std::string prefix;
+    if (prefix_view.empty()) {
         prefix = "tint_symbol";
+    } else {
+        prefix = std::string(prefix_view);
     }
+
     auto it = name_to_symbol_.Find(prefix);
     if (!it) {
-        return Register(prefix);
+        return RegisterInternal(prefix);
     }
 
     size_t i = 0;
@@ -77,13 +82,13 @@ Symbol SymbolTable::New(std::string prefix /* = "" */) {
         name = prefix + "_" + std::to_string(i);
     } while (name_to_symbol_.Contains(name));
 
+    auto sym = RegisterInternal(name);
     if (last_prefix) {
         *last_prefix = i;
     } else {
         last_prefix_to_index_.Add(prefix, i);
     }
-
-    return Register(name);
+    return sym;
 }
 
 }  // namespace tint

src/tint/symbol_table.h

@@ -56,12 +56,12 @@ class SymbolTable {
     /// Registers a name into the symbol table, returning the Symbol.
     /// @param name the name to register
     /// @returns the symbol representing the given name
-    Symbol Register(const std::string& name);
+    Symbol Register(std::string_view name);
 
     /// Returns the symbol for the given `name`
     /// @param name the name to lookup
     /// @returns the symbol for the name or Symbol() if not found.
-    Symbol Get(const std::string& name) const;
+    Symbol Get(std::string_view name) const;
 
     /// Returns a new unique symbol with the given name, possibly suffixed with a
     /// unique number.
@@ -69,7 +69,7 @@ class SymbolTable {
     /// @returns a new, unnamed symbol with the given name. If the name is already
     /// taken then this will be suffixed with an underscore and a unique numerical
     /// value
-    Symbol New(std::string name = "");
+    Symbol New(std::string_view name = "");
 
     /// Foreach calls the callback function `F` for each symbol in the table.
     /// @param callback must be a function or function-like object with the
@@ -88,6 +88,8 @@ class SymbolTable {
     SymbolTable(const SymbolTable&) = delete;
     SymbolTable& operator=(const SymbolTable& other) = delete;
 
+    Symbol RegisterInternal(std::string_view name);
+
     // The value to be associated to the next registered symbol table entry.
     uint32_t next_symbol_ = 1;