Calculate TFunction::mangledName lazily.

This saves us ~15KiB per compiler instance on 32-bit Android.

BUG=492725

Change-Id: I9db2998482941b5ab2eb5cb4925cbd1fb58ab4be
Reviewed-on: https://chromium-review.googlesource.com/283584
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/translator/SymbolTable.cpp b/src/compiler/translator/SymbolTable.cpp
index 35887d0..27f5579 100644
--- a/src/compiler/translator/SymbolTable.cpp
+++ b/src/compiler/translator/SymbolTable.cpp
@@ -29,6 +29,18 @@
         delete (*i).type;
 }
 
+const TString *TFunction::buildMangledName() const
+{
+    std::string mangledName = mangleName(getName()).c_str();
+
+    for (const auto &p : parameters)
+    {
+        mangledName += p.type->getMangledName().c_str();
+    }
+
+    return NewPoolTString(mangledName.c_str());
+}
+
 //
 // Symbol table levels are a map of pointers to symbols that have to be deleted.
 //