From 74c4daaadf485a951f1474ae94ed3c7dbdf87c69 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Oliver=20St=C3=B6neberg?=
 <firewave@users.noreply.github.com>
Date: Fri, 18 Aug 2023 20:41:50 +0200
Subject: [PATCH] optimized `Token::Match()` a bit by always inlining
 `Token::multiCompare()` (#5332)

Scanning `mame_regtest` with `DISABLE_VALUEFLOW=1` and `--enable=all
--inconclusive`:

Clang 15 `1,170,770,173` -> `1,167,227,434`
GGC 12 `1,370,070,422` -> `1,366,775,852`
---
 lib/token.cpp | 23 ++++++++++++++++++++---
 lib/token.h   |  4 ++++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/lib/token.cpp b/lib/token.cpp
index 618979613..5259a7d6b 100644
--- a/lib/token.cpp
+++ b/lib/token.cpp
@@ -424,7 +424,13 @@ const std::string &Token::strAt(int index) const
     return tok ? tok->mStr : emptyString;
 }
 
-static int multiComparePercent(const Token *tok, const char*& haystack, nonneg int varid)
+static
+#if defined(__GNUC__)
+// GCC does not inline this by itself
+// need to use the old syntax since the C++11 [[xxx:always_inline]] cannot be used here
+inline __attribute__((always_inline))
+#endif
+int multiComparePercent(const Token *tok, const char*& haystack, nonneg int varid)
 {
     ++haystack;
     // Compare only the first character of the string for optimization reasons
@@ -556,7 +562,12 @@ static int multiComparePercent(const Token *tok, const char*& haystack, nonneg i
     return 0xFFFF;
 }
 
-int Token::multiCompare(const Token *tok, const char *haystack, nonneg int varid)
+static
+#if defined(__GNUC__)
+// need to use the old syntax since the C++11 [[xxx:always_inline]] cannot be used here
+inline __attribute__((always_inline))
+#endif
+int multiCompareImpl(const Token *tok, const char *haystack, nonneg int varid)
 {
     const char *needle = tok->str().c_str();
     const char *needlePointer = needle;
@@ -609,6 +620,12 @@ int Token::multiCompare(const Token *tok, const char *haystack, nonneg int varid
     return -1;
 }
 
+// cppcheck-suppress unusedFunction - used in tests only
+int Token::multiCompare(const Token *tok, const char *haystack, nonneg int varid)
+{
+    return multiCompareImpl(tok, haystack, varid);
+}
+
 bool Token::simpleMatch(const Token *tok, const char pattern[], size_t pattern_len)
 {
     if (!tok)
@@ -730,7 +747,7 @@ bool Token::Match(const Token *tok, const char pattern[], nonneg int varid)
 
         // Parse multi options, such as void|int|char (accept token which is one of these 3)
         else {
-            const int res = multiCompare(tok, p, varid);
+            const int res = multiCompareImpl(tok, p, varid);
             if (res == 0) {
                 // Empty alternative matches, use the same token on next round
                 while (*p && *p != ' ')
diff --git a/lib/token.h b/lib/token.h
index e0ca0ed9d..b17c294bd 100644
--- a/lib/token.h
+++ b/lib/token.h
@@ -154,6 +154,8 @@ struct TokenImpl {
  * The Token class also has other functions for management of token list, matching tokens, etc.
  */
 class CPPCHECKLIB Token {
+    friend class TestToken;
+
 private:
     TokensFrontBack* mTokensFrontBack{};
 
@@ -788,6 +790,7 @@ public:
         return const_cast<Token *>(findmatch(const_cast<const Token *>(startTok), pattern, end, varId));
     }
 
+private:
     /**
      * Needle is build from multiple alternatives. If one of
      * them is equal to haystack, return value is 1. If there
@@ -804,6 +807,7 @@ public:
      */
     static int multiCompare(const Token *tok, const char *haystack, nonneg int varid);
 
+public:
     nonneg int fileIndex() const {
         return mImpl->mFileIndex;
     }