Pass large types by const&, small types by value

Source/cmCacheManager.cxx

@@ -205,8 +205,7 @@ bool cmCacheManager::ReadPropertyEntry(std::string const& entryKey,
   return false;
 }
 
-void cmCacheManager::WritePropertyEntries(std::ostream& os,
-                                          CacheIterator const& i)
+void cmCacheManager::WritePropertyEntries(std::ostream& os, CacheIterator i)
 {
   for (const char** p = this->PersistentProperties; *p; ++p) {
     if (const char* value = i.GetProperty(*p)) {

Source/cmCacheManager.h

@@ -228,7 +228,7 @@ private:
 
   static const char* PersistentProperties[];
   bool ReadPropertyEntry(std::string const& key, CacheEntry& e);
-  void WritePropertyEntries(std::ostream& os, CacheIterator const& i);
+  void WritePropertyEntries(std::ostream& os, CacheIterator i);
 
   CacheEntryMap Cache;
   // Only cmake and cmState should be able to add cache values

Source/cmComputeLinkDepends.cxx

@@ -333,7 +333,7 @@ int cmComputeLinkDepends::AddLinkEntry(cmLinkItem const& item)
   return index;
 }
 
-void cmComputeLinkDepends::FollowLinkEntry(BFSEntry const& qe)
+void cmComputeLinkDepends::FollowLinkEntry(BFSEntry qe)
 {
   // Get this entry representation.
   int depender_index = qe.Index;

Source/cmComputeLinkDepends.h

@@ -93,7 +93,7 @@ private:
     const char* LibDepends;
   };
   std::queue<BFSEntry> BFSQueue;
-  void FollowLinkEntry(BFSEntry const&);
+  void FollowLinkEntry(BFSEntry qe);
 
   // Shared libraries that are included only because they are
   // dependencies of other shared libraries, not because they are part

Source/cmDynamicLoader.cxx

@@ -10,8 +10,7 @@ class cmDynamicLoaderCache
 {
 public:
   ~cmDynamicLoaderCache();
-  void CacheFile(const char* path,
-                 const cmsys::DynamicLoader::LibraryHandle& /*p*/);
+  void CacheFile(const char* path, cmsys::DynamicLoader::LibraryHandle /*p*/);
   bool GetCacheFile(const char* path,
                     cmsys::DynamicLoader::LibraryHandle& /*p*/);
   bool FlushCache(const char* path);
@@ -29,8 +28,8 @@ cmDynamicLoaderCache::~cmDynamicLoaderCache()
 {
 }
 
-void cmDynamicLoaderCache::CacheFile(
-  const char* path, const cmsys::DynamicLoader::LibraryHandle& p)
+void cmDynamicLoaderCache::CacheFile(const char* path,
+                                     cmsys::DynamicLoader::LibraryHandle p)
 {
   cmsys::DynamicLoader::LibraryHandle h;
   if (this->GetCacheFile(path, h)) {

Source/cmELF.cxx

@@ -53,17 +53,17 @@ template <size_t s>
 struct cmELFByteSwapSize
 {
 };
-void cmELFByteSwap(char* /*unused*/, cmELFByteSwapSize<1> const& /*unused*/)
+void cmELFByteSwap(char* /*unused*/, cmELFByteSwapSize<1> /*unused*/)
 {
 }
-void cmELFByteSwap(char* data, cmELFByteSwapSize<2> const& /*unused*/)
+void cmELFByteSwap(char* data, cmELFByteSwapSize<2> /*unused*/)
 {
   char one_byte;
   one_byte = data[0];
   data[0] = data[1];
   data[1] = one_byte;
 }
-void cmELFByteSwap(char* data, cmELFByteSwapSize<4> const& /*unused*/)
+void cmELFByteSwap(char* data, cmELFByteSwapSize<4> /*unused*/)
 {
   char one_byte;
   one_byte = data[0];
@@ -73,7 +73,7 @@ void cmELFByteSwap(char* data, cmELFByteSwapSize<4> const& /*unused*/)
   data[1] = data[2];
   data[2] = one_byte;
 }
-void cmELFByteSwap(char* data, cmELFByteSwapSize<8> const& /*unused*/)
+void cmELFByteSwap(char* data, cmELFByteSwapSize<8> /*unused*/)
 {
   char one_byte;
   one_byte = data[0];

Source/cmFileCommand.cxx

@@ -1121,9 +1121,9 @@ protected:
 
   bool InstallSymlink(const char* fromFile, const char* toFile);
   bool InstallFile(const char* fromFile, const char* toFile,
-                   MatchProperties const& match_properties);
+                   MatchProperties match_properties);
   bool InstallDirectory(const char* source, const char* destination,
-                        MatchProperties const& match_properties);
+                        MatchProperties match_properties);
   virtual bool Install(const char* fromFile, const char* toFile);
   virtual std::string const& ToName(std::string const& fromName)
   {
@@ -1542,7 +1542,7 @@ bool cmFileCopier::InstallSymlink(const char* fromFile, const char* toFile)
 }
 
 bool cmFileCopier::InstallFile(const char* fromFile, const char* toFile,
-                               MatchProperties const& match_properties)
+                               MatchProperties match_properties)
 {
   // Determine whether we will copy the file.
   bool copy = true;
@@ -1596,7 +1596,7 @@ bool cmFileCopier::InstallFile(const char* fromFile, const char* toFile,
 
 bool cmFileCopier::InstallDirectory(const char* source,
                                     const char* destination,
-                                    MatchProperties const& match_properties)
+                                    MatchProperties match_properties)
 {
   // Inform the user about this directory installation.
   this->ReportCopy(destination, TypeDir,

Source/cmFindProgramCommand.cxx

@@ -212,7 +212,8 @@ std::string cmFindProgramCommand::FindAppBundle()
   return "";
 }
 
-std::string cmFindProgramCommand::GetBundleExecutable(std::string bundlePath)
+std::string cmFindProgramCommand::GetBundleExecutable(
+  std::string const& bundlePath)
 {
   std::string executable;
   (void)bundlePath;

Source/cmFindProgramCommand.h

@@ -43,7 +43,7 @@ private:
   std::string FindNormalProgramDirsPerName();
   std::string FindNormalProgramNamesPerDir();
   std::string FindAppBundle();
-  std::string GetBundleExecutable(std::string bundlePath);
+  std::string GetBundleExecutable(std::string const& bundlePath);
 };
 
 #endif

Source/cmGeneratorTarget.cxx

@@ -76,7 +76,7 @@ public:
 cmLinkImplItem cmGeneratorTarget::TargetPropertyEntry::NoLinkImplItem;
 
 void CreatePropertyGeneratorExpressions(
-  cmStringRange const& entries, cmBacktraceRange const& backtraces,
+  cmStringRange entries, cmBacktraceRange backtraces,
   std::vector<cmGeneratorTarget::TargetPropertyEntry*>& items,
   bool evaluateForBuildsystem = false)
 {

Source/cmGlobalGenerator.cxx

@@ -1482,13 +1482,13 @@ cmGlobalGenerator::CreateQtAutoGeneratorsTargets()
 }
 
 cmLinkLineComputer* cmGlobalGenerator::CreateLinkLineComputer(
-  cmOutputConverter* outputConverter, cmStateDirectory stateDir) const
+  cmOutputConverter* outputConverter, cmStateDirectory const& stateDir) const
 {
   return new cmLinkLineComputer(outputConverter, stateDir);
 }
 
 cmLinkLineComputer* cmGlobalGenerator::CreateMSVC60LinkLineComputer(
-  cmOutputConverter* outputConverter, cmStateDirectory stateDir) const
+  cmOutputConverter* outputConverter, cmStateDirectory const& stateDir) const
 {
   return new cmMSVC60LinkLineComputer(outputConverter, stateDir);
 }

Source/cmGlobalGenerator.h

@@ -105,10 +105,12 @@ public:
   virtual void Generate();
 
   virtual cmLinkLineComputer* CreateLinkLineComputer(
-    cmOutputConverter* outputConverter, cmStateDirectory stateDir) const;
+    cmOutputConverter* outputConverter,
+    cmStateDirectory const& stateDir) const;
 
   cmLinkLineComputer* CreateMSVC60LinkLineComputer(
-    cmOutputConverter* outputConverter, cmStateDirectory stateDir) const;
+    cmOutputConverter* outputConverter,
+    cmStateDirectory const& stateDir) const;
 
   /**
    * Set/Get and Clear the enabled languages.

Source/cmGlobalNinjaGenerator.cxx

@@ -77,7 +77,8 @@ void cmGlobalNinjaGenerator::WriteComment(std::ostream& os,
 }
 
 cmLinkLineComputer* cmGlobalNinjaGenerator::CreateLinkLineComputer(
-  cmOutputConverter* outputConverter, cmStateDirectory /* stateDir */) const
+  cmOutputConverter* outputConverter,
+  cmStateDirectory const& /* stateDir */) const
 {
   return new cmNinjaLinkLineComputer(
     outputConverter,

Source/cmGlobalNinjaGenerator.h

@@ -78,7 +78,7 @@ public:
 
   cmLinkLineComputer* CreateLinkLineComputer(
     cmOutputConverter* outputConverter,
-    cmStateDirectory stateDir) const CM_OVERRIDE;
+    cmStateDirectory const& stateDir) const CM_OVERRIDE;
 
   /**
    * Write the given @a comment to the output stream @a os. It

Source/cmInstallGenerator.cxx

@@ -27,7 +27,7 @@ void cmInstallGenerator::AddInstallRule(
   std::vector<std::string> const& files, bool optional /* = false */,
   const char* permissions_file /* = 0 */,
   const char* permissions_dir /* = 0 */, const char* rename /* = 0 */,
-  const char* literal_args /* = 0 */, Indent const& indent)
+  const char* literal_args /* = 0 */, Indent indent)
 {
   // Use the FILE command to install the file.
   std::string stype;

Source/cmInstallGenerator.h

@@ -43,7 +43,7 @@ public:
     std::vector<std::string> const& files, bool optional = false,
     const char* permissions_file = CM_NULLPTR,
     const char* permissions_dir = CM_NULLPTR, const char* rename = CM_NULLPTR,
-    const char* literal_args = CM_NULLPTR, Indent const& indent = Indent());
+    const char* literal_args = CM_NULLPTR, Indent indent = Indent());
 
   /** Get the install destination as it should appear in the
       installation script.  */

Source/cmLinkLineComputer.cxx

@@ -13,7 +13,7 @@
 #include "cmStateTypes.h"
 
 cmLinkLineComputer::cmLinkLineComputer(cmOutputConverter* outputConverter,
-                                       cmStateDirectory stateDir)
+                                       cmStateDirectory const& stateDir)
   : StateDir(stateDir)
   , OutputConverter(outputConverter)
   , ForResponse(false)

Source/cmLinkLineComputer.h

@@ -20,7 +20,7 @@ class cmLinkLineComputer
 
 public:
   cmLinkLineComputer(cmOutputConverter* outputConverter,
-                     cmStateDirectory stateDir);
+                     cmStateDirectory const& stateDir);
   virtual ~cmLinkLineComputer();
 
   void SetUseWatcomQuote(bool useWatcomQuote);

Source/cmLinkLineDeviceComputer.cxx

@@ -10,13 +10,12 @@
 #include "cmComputeLinkInformation.h"
 #include "cmGeneratorTarget.h"
 #include "cmGlobalNinjaGenerator.h"
-#include "cmStateDirectory.h"
 #include "cmStateTypes.h"
 
 class cmOutputConverter;
 
 cmLinkLineDeviceComputer::cmLinkLineDeviceComputer(
-  cmOutputConverter* outputConverter, cmStateDirectory stateDir)
+  cmOutputConverter* outputConverter, cmStateDirectory const& stateDir)
   : cmLinkLineComputer(outputConverter, stateDir)
 {
 }
@@ -89,7 +88,7 @@ std::string cmLinkLineDeviceComputer::GetLinkerLanguage(cmGeneratorTarget*,
 }
 
 cmNinjaLinkLineDeviceComputer::cmNinjaLinkLineDeviceComputer(
-  cmOutputConverter* outputConverter, cmStateDirectory stateDir,
+  cmOutputConverter* outputConverter, cmStateDirectory const& stateDir,
   cmGlobalNinjaGenerator const* gg)
   : cmLinkLineDeviceComputer(outputConverter, stateDir)
   , GG(gg)

Source/cmLinkLineDeviceComputer.h

@@ -22,7 +22,7 @@ class cmLinkLineDeviceComputer : public cmLinkLineComputer
 
 public:
   cmLinkLineDeviceComputer(cmOutputConverter* outputConverter,
-                           cmStateDirectory stateDir);
+                           cmStateDirectory const& stateDir);
   ~cmLinkLineDeviceComputer() CM_OVERRIDE;
 
   std::string ComputeLinkLibraries(cmComputeLinkInformation& cli,
@@ -39,7 +39,7 @@ class cmNinjaLinkLineDeviceComputer : public cmLinkLineDeviceComputer
 
 public:
   cmNinjaLinkLineDeviceComputer(cmOutputConverter* outputConverter,
-                                cmStateDirectory stateDir,
+                                cmStateDirectory const& stateDir,
                                 cmGlobalNinjaGenerator const* gg);
 
   std::string ConvertToLinkReference(std::string const& input) const

Source/cmListFileCache.cxx

@@ -307,7 +307,8 @@ struct cmListFileBacktrace::Entry : public cmListFileContext
   unsigned int RefCount;
 };
 
-cmListFileBacktrace::cmListFileBacktrace(cmStateSnapshot bottom, Entry* up,
+cmListFileBacktrace::cmListFileBacktrace(cmStateSnapshot const& bottom,
+                                         Entry* up,
                                          cmListFileContext const& lfc)
   : Bottom(bottom)
   , Cur(new Entry(lfc, up))
@@ -316,7 +317,8 @@ cmListFileBacktrace::cmListFileBacktrace(cmStateSnapshot bottom, Entry* up,
   this->Cur->Ref();
 }
 
-cmListFileBacktrace::cmListFileBacktrace(cmStateSnapshot bottom, Entry* cur)
+cmListFileBacktrace::cmListFileBacktrace(cmStateSnapshot const& bottom,
+                                         Entry* cur)
   : Bottom(bottom)
   , Cur(cur)
 {
@@ -332,7 +334,7 @@ cmListFileBacktrace::cmListFileBacktrace()
 {
 }
 
-cmListFileBacktrace::cmListFileBacktrace(cmStateSnapshot snapshot)
+cmListFileBacktrace::cmListFileBacktrace(cmStateSnapshot const& snapshot)
   : Bottom(snapshot.GetCallStackBottom())
   , Cur(CM_NULLPTR)
 {

Source/cmListFileCache.h

@@ -107,7 +107,7 @@ public:
 
   // Construct an empty backtrace whose bottom sits in the directory
   // indicated by the given valid snapshot.
-  cmListFileBacktrace(cmStateSnapshot snapshot);
+  cmListFileBacktrace(cmStateSnapshot const& snapshot);
 
   // Backtraces may be copied and assigned as values.
   cmListFileBacktrace(cmListFileBacktrace const& r);
@@ -143,9 +143,9 @@ private:
 
   cmStateSnapshot Bottom;
   Entry* Cur;
-  cmListFileBacktrace(cmStateSnapshot bottom, Entry* up,
+  cmListFileBacktrace(cmStateSnapshot const& bottom, Entry* up,
                       cmListFileContext const& lfc);
-  cmListFileBacktrace(cmStateSnapshot bottom, Entry* cur);
+  cmListFileBacktrace(cmStateSnapshot const& bottom, Entry* cur);
 };
 
 struct cmListFile

Source/cmMSVC60LinkLineComputer.cxx

@@ -3,8 +3,6 @@
 
 #include "cmMSVC60LinkLineComputer.h"
 
-#include "cmStateDirectory.h"
-
 #if defined(_WIN32) && !defined(__CYGWIN__)
 #include "cmSystemTools.h"
 #endif
@@ -12,7 +10,7 @@
 class cmOutputConverter;
 
 cmMSVC60LinkLineComputer::cmMSVC60LinkLineComputer(
-  cmOutputConverter* outputConverter, cmStateDirectory stateDir)
+  cmOutputConverter* outputConverter, cmStateDirectory const& stateDir)
   : cmLinkLineComputer(outputConverter, stateDir)
 {
 }

Source/cmMSVC60LinkLineComputer.h

@@ -19,7 +19,7 @@ class cmMSVC60LinkLineComputer : public cmLinkLineComputer
 
 public:
   cmMSVC60LinkLineComputer(cmOutputConverter* outputConverter,
-                           cmStateDirectory stateDir);
+                           cmStateDirectory const& stateDir);
 
   std::string ConvertToLinkReference(std::string const& input) const
     CM_OVERRIDE;

Source/cmMakefile.cxx

@@ -3463,7 +3463,7 @@ void cmMakefile::ConfigureString(const std::string& input, std::string& output,
 
 int cmMakefile::ConfigureFile(const char* infile, const char* outfile,
                               bool copyonly, bool atOnly, bool escapeQuotes,
-                              const cmNewLineStyle& newLine)
+                              cmNewLineStyle newLine)
 {
   int res = 1;
   if (!this->CanIWriteThisFile(outfile)) {

Source/cmMakefile.h

@@ -548,7 +548,7 @@ public:
    */
   int ConfigureFile(const char* infile, const char* outfile, bool copyonly,
                     bool atOnly, bool escapeQuotes,
-                    const cmNewLineStyle& = cmNewLineStyle());
+                    cmNewLineStyle = cmNewLineStyle());
 
 #if defined(CMAKE_BUILD_WITH_CMAKE)
   /**

Source/cmMakefileTargetGenerator.cxx

@@ -1255,7 +1255,7 @@ class cmMakefileTargetGeneratorObjectStrings
 public:
   cmMakefileTargetGeneratorObjectStrings(std::vector<std::string>& strings,
                                          cmOutputConverter* outputConverter,
-                                         cmStateDirectory stateDir,
+                                         cmStateDirectory const& stateDir,
                                          std::string::size_type limit)
     : Strings(strings)
     , OutputConverter(outputConverter)
@@ -1574,7 +1574,7 @@ std::string cmMakefileTargetGenerator::CreateResponseFile(
 }
 
 cmLinkLineComputer* cmMakefileTargetGenerator::CreateLinkLineComputer(
-  cmOutputConverter* outputConverter, cmStateDirectory stateDir)
+  cmOutputConverter* outputConverter, cmStateDirectory const& stateDir)
 {
   if (this->Makefile->IsOn("MSVC60")) {
     return this->GlobalGenerator->CreateMSVC60LinkLineComputer(outputConverter,

Source/cmMakefileTargetGenerator.h

@@ -143,7 +143,7 @@ protected:
                         std::vector<std::string>& makefile_depends);
 
   cmLinkLineComputer* CreateLinkLineComputer(
-    cmOutputConverter* outputConverter, cmStateDirectory stateDir);
+    cmOutputConverter* outputConverter, cmStateDirectory const& stateDir);
 
   /** Create a response file with the given set of options.  Returns
       the relative path from the target build working directory to the

Source/cmNinjaLinkLineComputer.cxx

@@ -4,12 +4,11 @@
 #include "cmNinjaLinkLineComputer.h"
 
 #include "cmGlobalNinjaGenerator.h"
-#include "cmStateDirectory.h"
 
 class cmOutputConverter;
 
 cmNinjaLinkLineComputer::cmNinjaLinkLineComputer(
-  cmOutputConverter* outputConverter, cmStateDirectory stateDir,
+  cmOutputConverter* outputConverter, cmStateDirectory const& stateDir,
   cmGlobalNinjaGenerator const* gg)
   : cmLinkLineComputer(outputConverter, stateDir)
   , GG(gg)

Source/cmNinjaLinkLineComputer.h

@@ -20,7 +20,7 @@ class cmNinjaLinkLineComputer : public cmLinkLineComputer
 
 public:
   cmNinjaLinkLineComputer(cmOutputConverter* outputConverter,
-                          cmStateDirectory stateDir,
+                          cmStateDirectory const& stateDir,
                           cmGlobalNinjaGenerator const* gg);
 
   std::string ConvertToLinkReference(std::string const& input) const

Source/cmOrderDirectories.cxx

@@ -424,7 +424,7 @@ struct cmOrderDirectoriesCompare
   // The conflict pair is unique based on just the directory
   // (first).  The second element is only used for displaying
   // information about why the entry is present.
-  bool operator()(ConflictPair const& l, ConflictPair const& r)
+  bool operator()(ConflictPair l, ConflictPair r)
   {
     return l.first == r.first;
   }

Source/cmOutputConverter.cxx

@@ -14,7 +14,7 @@
 #include "cmStateDirectory.h"
 #include "cmSystemTools.h"
 
-cmOutputConverter::cmOutputConverter(cmStateSnapshot snapshot)
+cmOutputConverter::cmOutputConverter(cmStateSnapshot const& snapshot)
   : StateSnapshot(snapshot)
   , LinkScriptShell(false)
 {
@@ -81,7 +81,7 @@ static bool cmOutputConverterNotAbove(const char* a, const char* b)
 
 bool cmOutputConverter::ContainedInDirectory(std::string const& local_path,
                                              std::string const& remote_path,
-                                             cmStateDirectory directory)
+                                             cmStateDirectory const& directory)
 {
   const std::string relativePathTopBinary =
     directory.GetRelativePathTopBinary();

Source/cmOutputConverter.h

@@ -15,7 +15,7 @@ class cmStateDirectory;
 class cmOutputConverter
 {
 public:
-  cmOutputConverter(cmStateSnapshot snapshot);
+  cmOutputConverter(cmStateSnapshot const& snapshot);
 
   enum OutputFormat
   {
@@ -94,7 +94,7 @@ public:
 
   static bool ContainedInDirectory(std::string const& local_path,
                                    std::string const& remote_path,
-                                   cmStateDirectory directory);
+                                   cmStateDirectory const& directory);
 
   /**
    * Convert the given remote path to a relative path with respect to

Source/cmState.cxx

@@ -633,7 +633,7 @@ cmStateSnapshot cmState::CreateBaseSnapshot()
 }
 
 cmStateSnapshot cmState::CreateBuildsystemDirectorySnapshot(
-  cmStateSnapshot originSnapshot)
+  cmStateSnapshot const& originSnapshot)
 {
   assert(originSnapshot.IsValid());
   cmStateDetail::PositionType pos =
@@ -667,7 +667,7 @@ cmStateSnapshot cmState::CreateBuildsystemDirectorySnapshot(
 }
 
 cmStateSnapshot cmState::CreateFunctionCallSnapshot(
-  cmStateSnapshot originSnapshot, std::string const& fileName)
+  cmStateSnapshot const& originSnapshot, std::string const& fileName)
 {
   cmStateDetail::PositionType pos =
     this->SnapshotData.Push(originSnapshot.Position, *originSnapshot.Position);
@@ -686,7 +686,7 @@ cmStateSnapshot cmState::CreateFunctionCallSnapshot(
 }
 
 cmStateSnapshot cmState::CreateMacroCallSnapshot(
-  cmStateSnapshot originSnapshot, std::string const& fileName)
+  cmStateSnapshot const& originSnapshot, std::string const& fileName)
 {
   cmStateDetail::PositionType pos =
     this->SnapshotData.Push(originSnapshot.Position, *originSnapshot.Position);
@@ -701,7 +701,7 @@ cmStateSnapshot cmState::CreateMacroCallSnapshot(
 }
 
 cmStateSnapshot cmState::CreateIncludeFileSnapshot(
-  cmStateSnapshot originSnapshot, const std::string& fileName)
+  cmStateSnapshot const& originSnapshot, std::string const& fileName)
 {
   cmStateDetail::PositionType pos =
     this->SnapshotData.Push(originSnapshot.Position, *originSnapshot.Position);
@@ -716,7 +716,7 @@ cmStateSnapshot cmState::CreateIncludeFileSnapshot(
 }
 
 cmStateSnapshot cmState::CreateVariableScopeSnapshot(
-  cmStateSnapshot originSnapshot)
+  cmStateSnapshot const& originSnapshot)
 {
   cmStateDetail::PositionType pos =
     this->SnapshotData.Push(originSnapshot.Position, *originSnapshot.Position);
@@ -734,7 +734,7 @@ cmStateSnapshot cmState::CreateVariableScopeSnapshot(
 }
 
 cmStateSnapshot cmState::CreateInlineListFileSnapshot(
-  cmStateSnapshot originSnapshot, const std::string& fileName)
+  cmStateSnapshot const& originSnapshot, std::string const& fileName)
 {
   cmStateDetail::PositionType pos =
     this->SnapshotData.Push(originSnapshot.Position, *originSnapshot.Position);
@@ -748,7 +748,7 @@ cmStateSnapshot cmState::CreateInlineListFileSnapshot(
 }
 
 cmStateSnapshot cmState::CreatePolicyScopeSnapshot(
-  cmStateSnapshot originSnapshot)
+  cmStateSnapshot const& originSnapshot)
 {
   cmStateDetail::PositionType pos =
     this->SnapshotData.Push(originSnapshot.Position, *originSnapshot.Position);
@@ -759,7 +759,7 @@ cmStateSnapshot cmState::CreatePolicyScopeSnapshot(
   return cmStateSnapshot(this, pos);
 }
 
-cmStateSnapshot cmState::Pop(cmStateSnapshot originSnapshot)
+cmStateSnapshot cmState::Pop(cmStateSnapshot const& originSnapshot)
 {
   cmStateDetail::PositionType pos = originSnapshot.Position;
   cmStateDetail::PositionType prevPos = pos;

Source/cmState.h

@@ -36,18 +36,20 @@ public:
 
   cmStateSnapshot CreateBaseSnapshot();
   cmStateSnapshot CreateBuildsystemDirectorySnapshot(
-    cmStateSnapshot originSnapshot);
-  cmStateSnapshot CreateFunctionCallSnapshot(cmStateSnapshot originSnapshot,
-                                             std::string const& fileName);
-  cmStateSnapshot CreateMacroCallSnapshot(cmStateSnapshot originSnapshot,
-                                          std::string const& fileName);
-  cmStateSnapshot CreateIncludeFileSnapshot(cmStateSnapshot originSnapshot,
-                                            std::string const& fileName);
-  cmStateSnapshot CreateVariableScopeSnapshot(cmStateSnapshot originSnapshot);
-  cmStateSnapshot CreateInlineListFileSnapshot(cmStateSnapshot originSnapshot,
-                                               std::string const& fileName);
-  cmStateSnapshot CreatePolicyScopeSnapshot(cmStateSnapshot originSnapshot);
-  cmStateSnapshot Pop(cmStateSnapshot originSnapshot);
+    cmStateSnapshot const& originSnapshot);
+  cmStateSnapshot CreateFunctionCallSnapshot(
+    cmStateSnapshot const& originSnapshot, std::string const& fileName);
+  cmStateSnapshot CreateMacroCallSnapshot(
+    cmStateSnapshot const& originSnapshot, std::string const& fileName);
+  cmStateSnapshot CreateIncludeFileSnapshot(
+    cmStateSnapshot const& originSnapshot, std::string const& fileName);
+  cmStateSnapshot CreateVariableScopeSnapshot(
+    cmStateSnapshot const& originSnapshot);
+  cmStateSnapshot CreateInlineListFileSnapshot(
+    cmStateSnapshot const& originSnapshot, std::string const& fileName);
+  cmStateSnapshot CreatePolicyScopeSnapshot(
+    cmStateSnapshot const& originSnapshot);
+  cmStateSnapshot Pop(cmStateSnapshot const& originSnapshot);
 
   static cmStateEnums::CacheEntryType StringToCacheEntryType(const char*);
   static const char* CacheEntryTypeToString(cmStateEnums::CacheEntryType);

Source/cmStateSnapshot.cxx

@@ -125,7 +125,7 @@ cmStateSnapshot cmStateSnapshot::GetCallStackBottom() const
   return cmStateSnapshot(this->State, pos);
 }
 
-void cmStateSnapshot::PushPolicy(cmPolicies::PolicyMap entry, bool weak)
+void cmStateSnapshot::PushPolicy(cmPolicies::PolicyMap const& entry, bool weak)
 {
   cmStateDetail::PositionType pos = this->Position;
   pos->Policies = this->State->PolicyStack.Push(

Source/cmStateSnapshot.h

@@ -45,7 +45,7 @@ public:
   void SetPolicy(cmPolicies::PolicyID id, cmPolicies::PolicyStatus status);
   cmPolicies::PolicyStatus GetPolicy(cmPolicies::PolicyID id) const;
   bool HasDefinedPolicyCMP0011();
-  void PushPolicy(cmPolicies::PolicyMap entry, bool weak);
+  void PushPolicy(cmPolicies::PolicyMap const& entry, bool weak);
   bool PopPolicy();
   bool CanPopPolicyScope();