Changeset 8abca06 for src

Timestamp:

Feb 11, 2020, 3:15:42 PM (4 years ago)

Author:

Peter A. Buhr <pabuhr@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

eeaa3e2

Parents:

7102540

Message:

rewrite isPrefix using memcmp to increase performance, same change in Demangle but untested

Location:

src

Files:

• Common/utility.h (modified) (3 diffs)
• SymTab/Demangle.cc (modified) (4 diffs)

src/Common/utility.h

@@ -10 +10 @@
 // Created On       : Mon May 18 07:44:20 2015
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Wed Jul 24 14:28:19 2019
-// Update Count     : 41
+// Last Modified On : Tue Feb 11 13:00:36 2020
+// Update Count     : 50
 //
 
@@ -29 +29 @@
 #include <utility>
 #include <vector>
+#include <cstring>                                                                              // memcmp
 
 #include "Common/Indenter.h"
@@ -264 +265 @@
 }
 
-/// determines if `pref` is a prefix of `str`
-static inline bool isPrefix( const std::string & str, const std::string & pref ) {
+// determines if pref is a prefix of str
+static inline bool isPrefix( const std::string & str, const std::string & pref, unsigned int start = 0 ) {
         if ( pref.size() > str.size() ) return false;
-        auto its = std::mismatch( pref.begin(), pref.end(), str.begin() );
-        return its.first == pref.end();
+    return 0 == memcmp( str.c_str() + start, pref.c_str(), pref.size() );
+        // return prefix == full.substr(0, prefix.size()); // for future, requires c++17
 }
 

src/SymTab/Demangle.cc

@@ -10 +10 @@
 // Created On       : Thu Jul 19 12:52:41 2018
 // Last Modified By : Peter A. Buhr
-// Last Modified On : Fri Dec 13 14:54:15 2019
-// Update Count     : 4
+// Last Modified On : Tue Feb 11 15:09:18 2020
+// Update Count     : 10
 //
 
@@ -19 +19 @@
 #include "CodeGen/GenType.h"
 #include "Common/PassVisitor.h"
+#include "Common/utility.h"                                                             // isPrefix
 #include "Mangler.h"
 #include "SynTree/Type.h"
@@ -416 +417 @@
 
                         bool StringView::isPrefix(const std::string & pref) {
-                                if ( pref.size() > str.size()-idx ) return false;
-                                auto its = std::mismatch( pref.begin(), pref.end(), std::next(str.begin(), idx) );
-                                if (its.first == pref.end()) {
+                                // if ( pref.size() > str.size()-idx ) return false;
+                                // auto its = std::mismatch( pref.begin(), pref.end(), std::next(str.begin(), idx) );
+                                // if (its.first == pref.end()) {
+                                //      idx += pref.size();
+                                //      return true;
+                                // }
+
+                                // This update is untested because there are no tests for this code.
+                                if ( ::isPrefix( str, pref, idx ) ) {
                                         idx += pref.size();
                                         return true;
@@ -429 +436 @@
                                 PRINT( std::cerr << "====== " << str.size() << " " << str << std::endl; )
                                 if (str.size() < 2+Encoding::manglePrefix.size()) return false; // +2 for at least _1 suffix
-                                if (! isPrefix(Encoding::manglePrefix) || ! isdigit(str.back())) return false;
+                                if ( ! isPrefix(Encoding::manglePrefix) || ! isdigit(str.back() ) ) return false;
 
                                 // get name