From 266bd003cab4532cf0b0bbf4ca899381bd9aa8ae Mon Sep 17 00:00:00 2001
From: Elinor Fung <elfung@microsoft.com>
Date: Wed, 16 Aug 2023 21:04:42 -0700
Subject: [PATCH] Switch fx_ver_t::as_str from stringstream to append/to_string
 (#90652)

Stop using std::stringstream to convert fx_ver_t to a string. It pulls in std::locale (and other things) in all the host binaries when we really just need a simple conversion of the numbers to a string. In some binaries, it was also the only usage of stringstream. On my local Windows builds, this was a 15 to 40 kB decrease in size for host entry point components. In theory, this should also be faster, although this is not a particularly perf-sensitive function (most usage is for when tracing is enabled).
---
 src/native/corehost/fxr/fx_ver.cpp           | 31 ++++++--------------
 src/native/corehost/fxr/fx_ver.h             |  2 --
 src/native/corehost/hostmisc/pal.unix.cpp    |  1 -
 src/native/corehost/hostmisc/pal.windows.cpp |  1 -
 src/native/corehost/hostpolicy/version.cpp   | 16 +++++-----
 5 files changed, 18 insertions(+), 33 deletions(-)

diff --git a/src/native/corehost/fxr/fx_ver.cpp b/src/native/corehost/fxr/fx_ver.cpp
index 254f408effe9b..7a857cdff473b 100644
--- a/src/native/corehost/fxr/fx_ver.cpp
+++ b/src/native/corehost/fxr/fx_ver.cpp
@@ -70,31 +70,18 @@ bool fx_ver_t::operator >=(const fx_ver_t& b) const
 
 pal::string_t fx_ver_t::as_str() const
 {
-    pal::stringstream_t stream;
-    stream << m_major << _X(".") << m_minor << _X(".") << m_patch;
+    pal::string_t version = pal::to_string(m_major);
+    version += _X('.');
+    version += pal::to_string(m_minor);
+    version += _X('.');
+    version += pal::to_string(m_patch);
     if (!m_pre.empty())
-    {
-        stream << m_pre;
-    }
-    if (!m_build.empty())
-    {
-        stream << m_build;
-    }
-    return stream.str();
-}
+        version += m_pre;
 
-pal::string_t fx_ver_t::prerelease_glob() const
-{
-    pal::stringstream_t stream;
-    stream << m_major << _X(".") << m_minor << _X(".") << m_patch << _X("-*");
-    return stream.str();
-}
+    if (!m_build.empty())
+        version += m_build;
 
-pal::string_t fx_ver_t::patch_glob() const
-{
-    pal::stringstream_t stream;
-    stream << m_major << _X(".") << m_minor << _X(".*");
-    return stream.str();
+    return version;
 }
 
 static pal::string_t getId(const pal::string_t &ids, size_t idStart)
diff --git a/src/native/corehost/fxr/fx_ver.h b/src/native/corehost/fxr/fx_ver.h
index 5f5348386897b..29f010876e04a 100644
--- a/src/native/corehost/fxr/fx_ver.h
+++ b/src/native/corehost/fxr/fx_ver.h
@@ -26,8 +26,6 @@ struct fx_ver_t
     bool is_empty() const { return m_major == -1; }
 
     pal::string_t as_str() const;
-    pal::string_t prerelease_glob() const;
-    pal::string_t patch_glob() const;
 
     bool operator ==(const fx_ver_t& b) const;
     bool operator !=(const fx_ver_t& b) const;
diff --git a/src/native/corehost/hostmisc/pal.unix.cpp b/src/native/corehost/hostmisc/pal.unix.cpp
index 46ffaf951adfb..34520aefd7365 100644
--- a/src/native/corehost/hostmisc/pal.unix.cpp
+++ b/src/native/corehost/hostmisc/pal.unix.cpp
@@ -16,7 +16,6 @@
 #include <fcntl.h>
 #include <fnmatch.h>
 #include <ctime>
-#include <locale>
 #include <pwd.h>
 #include "config.h"
 #include <minipal/getexepath.h>
diff --git a/src/native/corehost/hostmisc/pal.windows.cpp b/src/native/corehost/hostmisc/pal.windows.cpp
index 98e4efbed72f0..b11610492d321 100644
--- a/src/native/corehost/hostmisc/pal.windows.cpp
+++ b/src/native/corehost/hostmisc/pal.windows.cpp
@@ -7,7 +7,6 @@
 #include "longfile.h"
 
 #include <cassert>
-#include <locale>
 #include <ShlObj.h>
 #include <ctime>
 
diff --git a/src/native/corehost/hostpolicy/version.cpp b/src/native/corehost/hostpolicy/version.cpp
index ea643605ac88f..c08316fe4b5a8 100644
--- a/src/native/corehost/hostpolicy/version.cpp
+++ b/src/native/corehost/hostpolicy/version.cpp
@@ -51,29 +51,31 @@ bool version_t::operator >=(const version_t& b) const
 
 pal::string_t version_t::as_str() const
 {
-    pal::stringstream_t stream;
-
+    pal::string_t version;
     if (m_major >= 0)
     {
-        stream << m_major;
+        version += pal::to_string(m_major);
 
         if (m_minor >= 0)
         {
-            stream << _X(".") << m_minor;
+            version += _X('.');
+            version += pal::to_string(m_minor);
 
             if (m_build >= 0)
             {
-                stream << _X(".") << m_build;
+                version += _X('.');
+                version += pal::to_string(m_build);
 
                 if (m_revision >= 0)
                 {
-                    stream << _X(".") << m_revision;
+                    version += _X('.');
+                    version += pal::to_string(m_revision);
                 }
             }
         }
     }
 
-    return stream.str();
+    return version;
 }
 
 /*static*/ int version_t::compare(const version_t&a, const version_t& b)