cmELF: fix signedness warning on OpenBSD

OpenBSD defines Elf64_Dyn::d_tag to be of an unsigned type, which differs from
what most other platforms do and what is the case for 32 bit. To have the tag
as unsigned makes sense, but this causes a compilation warning:

/.../CMake/Source/cmELF.cxx: In member function 'const cmELF::StringEntry* cmELFInternalImpl<Types>::GetDynamicSectionString(int) [with Types = cmELFTypes64]':
/.../CMake/Source/cmELF.cxx:945:   instantiated from here
/.../CMake/Source/cmELF.cxx:668: warning: comparison between signed and unsigned integer expressions

Add an explicit typedef to cast the value to for 32 and 64 bit. That type is
unsigned and has the proper length for both platforms so no information is
lost. Explicitely cast both arguments before comparing them to avoid the
warning in all situations.

1 files changed, 9 insertions, 6 deletions

diff --git a/Source/cmELF.cxx b/Source/cmELF.cxx
index dc6772c..cab23b7 100644
--- a/Source/cmELF.cxx
+++ b/Source/cmELF.cxx
@@ -124,7 +124,7 @@ public:
   virtual unsigned int GetNumberOfSections() const = 0;
   virtual unsigned int GetDynamicEntryCount() = 0;
   virtual unsigned long GetDynamicEntryPosition(int j) = 0;
-  virtual StringEntry const* GetDynamicSectionString(int tag) = 0;
+  virtual StringEntry const* GetDynamicSectionString(unsigned int tag) = 0;
   virtual void PrintInfo(std::ostream& os) const = 0;
 
   bool ReadBytes(unsigned long pos, unsigned long size, char* buf)
@@ -187,7 +187,7 @@ protected:
     }
 
   // Store string table entry states.
-  std::map<int, StringEntry> DynamicSectionStrings;
+  std::map<unsigned int, StringEntry> DynamicSectionStrings;
 };
 
 //----------------------------------------------------------------------------
@@ -198,6 +198,7 @@ struct cmELFTypes32
   typedef Elf32_Shdr ELF_Shdr;
   typedef Elf32_Dyn  ELF_Dyn;
   typedef Elf32_Half ELF_Half;
+  typedef cmIML_INT_uint32_t tagtype;
   static const char* GetName() { return "32-bit"; }
 };
 
@@ -208,6 +209,7 @@ struct cmELFTypes64
   typedef Elf64_Shdr ELF_Shdr;
   typedef Elf64_Dyn  ELF_Dyn;
   typedef Elf64_Half ELF_Half;
+  typedef cmIML_INT_uint64_t tagtype;
   static const char* GetName() { return "64-bit"; }
 };
 
@@ -222,6 +224,7 @@ public:
   typedef typename Types::ELF_Shdr ELF_Shdr;
   typedef typename Types::ELF_Dyn  ELF_Dyn;
   typedef typename Types::ELF_Half ELF_Half;
+  typedef typename Types::tagtype tagtype;
 
   // Construct with a stream and byte swap indicator.
   cmELFInternalImpl(cmELF* external,
@@ -239,7 +242,7 @@ public:
   virtual unsigned long GetDynamicEntryPosition(int j);
 
   // Lookup a string from the dynamic section with the given tag.
-  virtual StringEntry const* GetDynamicSectionString(int tag);
+  virtual StringEntry const* GetDynamicSectionString(unsigned int tag);
 
   // Print information about the ELF file.
   virtual void PrintInfo(std::ostream& os) const
@@ -624,10 +627,10 @@ unsigned long cmELFInternalImpl<Types>::GetDynamicEntryPosition(int j)
 //----------------------------------------------------------------------------
 template <class Types>
 cmELF::StringEntry const*
-cmELFInternalImpl<Types>::GetDynamicSectionString(int tag)
+cmELFInternalImpl<Types>::GetDynamicSectionString(unsigned int tag)
 {
   // Short-circuit if already checked.
-  std::map<int, StringEntry>::iterator dssi =
+  std::map<unsigned int, StringEntry>::iterator dssi =
     this->DynamicSectionStrings.find(tag);
   if(dssi != this->DynamicSectionStrings.end())
     {
@@ -665,7 +668,7 @@ cmELFInternalImpl<Types>::GetDynamicSectionString(int tag)
       di != this->DynamicSectionEntries.end(); ++di)
     {
     ELF_Dyn& dyn = *di;
-    if(dyn.d_tag == tag)
+    if(static_cast<tagtype>(dyn.d_tag) == static_cast<tagtype>(tag))
       {
       // We found the tag requested.
       // Make sure the position given is within the string section.