Use uint64_t to store the ELF sh_entsize field.

[mattd]

Summary

Use 64bit sizes for sh_entsize.

Elf64_Shdr uses 64bit sizes (Elf64_Xword) to represent the section entry size
(sh_entsize). The internal LLVM representation maintains this field as a 32bit
value, regardless if Elf32 or Elf64. This change ensures that enormous
entsizes (values larger than 2^32) can be represented internally.

[mattd]

Ping.

I'm not certain how helpful this change is, per some discussion on the list last week, this change implies that linkers can also support extremely large sh_entsize values. The intention with this patch is to represent the same sh_entsize size used in elf.h for 64bit elfs.

include/llvm/MC/MCContext.h

 
     MCSectionELF *createELFSectionImpl(StringRef Section, unsigned Type,
                                        unsigned Flags, SectionKind K,
-                                       unsigned EntrySize,
+                                       uint64_t EntrySize,
                                        const MCSymbolELF *Group,
                                        unsigned UniqueID,
                                        const MCSymbolELF *Associated);

     }
 
     MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
-                                unsigned Flags, unsigned EntrySize,
+                                unsigned Flags, uint64_t EntrySize,
                                 const Twine &Group) {
       return getELFSection(Section, Type, Flags, EntrySize, Group, ~0);
     }
 
     MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
-                                unsigned Flags, unsigned EntrySize,
+                                unsigned Flags, uint64_t EntrySize,
                                 const Twine &Group, unsigned UniqueID) {
       return getELFSection(Section, Type, Flags, EntrySize, Group, UniqueID,
                            nullptr);

     }
 
     MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
-                                unsigned Flags, unsigned EntrySize,
+                                unsigned Flags, uint64_t EntrySize,
                                 const Twine &Group, unsigned UniqueID,
                                 const MCSymbolELF *Associated);
 
     MCSectionELF *getELFSection(const Twine &Section, unsigned Type,
-                                unsigned Flags, unsigned EntrySize,
+                                unsigned Flags, uint64_t EntrySize,
                                 const MCSymbolELF *Group, unsigned UniqueID,
                                 const MCSymbolELF *Associated);
 

     /// configure this named section.
     MCSectionELF *getELFNamedSection(const Twine &Prefix, const Twine &Suffix,
                                      unsigned Type, unsigned Flags,
-                                     unsigned EntrySize = 0);
+                                     uint64_t EntrySize = 0);
 
     MCSectionELF *createELFRelSection(const Twine &Name, unsigned Type,
-                                      unsigned Flags, unsigned EntrySize,
+                                      unsigned Flags, uint64_t EntrySize,
                                       const MCSymbolELF *Group,
                                       const MCSectionELF *RelInfoSection);
 

include/llvm/MC/MCSectionELF.h

 #include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCSymbolELF.h"
 #include "llvm/MC/SectionKind.h"
+#include <cstdint>
 
 namespace llvm {
 

 
   unsigned UniqueID;
 
-  /// The size of each entry in this section. This size only makes sense for
+  /// This is the sh_entsize field of a section. This size only makes sense for
   /// sections that contain fixed-sized entries. If a section does not contain
   /// fixed-sized entries 'EntrySize' will be 0.
-  unsigned EntrySize;
+  uint64_t EntrySize;
 
   const MCSymbolELF *Group;
 

   friend class MCContext;
 
   MCSectionELF(StringRef Section, unsigned type, unsigned flags, SectionKind K,
-               unsigned entrySize, const MCSymbolELF *group, unsigned UniqueID,
+               uint64_t entrySize, const MCSymbolELF *group, unsigned UniqueID,
                MCSymbol *Begin, const MCSymbolELF *AssociatedSymbol)
       : MCSection(SV_ELF, K, Begin), SectionName(Section), Type(type),
         Flags(flags), UniqueID(UniqueID), EntrySize(entrySize), Group(group),

   StringRef getSectionName() const { return SectionName; }
   unsigned getType() const { return Type; }
   unsigned getFlags() const { return Flags; }
-  unsigned getEntrySize() const { return EntrySize; }
+  uint64_t getEntrySize() const { return EntrySize; }
   void setFlags(unsigned F) { Flags = F; }
   const MCSymbolELF *getGroup() const { return Group; }
 

lib/MC/MCContext.cpp

 
 MCSectionELF *MCContext::createELFSectionImpl(StringRef Section, unsigned Type,
                                               unsigned Flags, SectionKind K,
-                                              unsigned EntrySize,
+                                              uint64_t EntrySize,
                                               const MCSymbolELF *Group,
                                               unsigned UniqueID,
                                               const MCSymbolELF *Associated) {

 }
 
 MCSectionELF *MCContext::createELFRelSection(const Twine &Name, unsigned Type,
-                                             unsigned Flags, unsigned EntrySize,
+                                             unsigned Flags, uint64_t EntrySize,
                                              const MCSymbolELF *Group,
                                              const MCSectionELF *RelInfoSection) {
   StringMap<bool>::iterator I;

 MCSectionELF *MCContext::getELFNamedSection(const Twine &Prefix,
                                             const Twine &Suffix, unsigned Type,
                                             unsigned Flags,
-                                            unsigned EntrySize) {
+                                            uint64_t EntrySize) {
   return getELFSection(Prefix + "." + Suffix, Type, Flags, EntrySize, Suffix);
 }
 
 MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type,
-                                       unsigned Flags, unsigned EntrySize,
+                                       unsigned Flags, uint64_t EntrySize,
                                        const Twine &Group, unsigned UniqueID,
                                        const MCSymbolELF *Associated) {
   MCSymbolELF *GroupSym = nullptr;

 }
 
 MCSectionELF *MCContext::getELFSection(const Twine &Section, unsigned Type,
-                                       unsigned Flags, unsigned EntrySize,
+                                       unsigned Flags, uint64_t EntrySize,
                                        const MCSymbolELF *GroupSym,
                                        unsigned UniqueID,
                                        const MCSymbolELF *Associated) {

test/MC/ELF/entsize.s

     .quad 42
     .quad 42
 
+ // Large sh_entsize
+  .section ".enormous_sh_entsize","M",@progbits,0x100000000
+
 // CHECK:        Section {
 // CHECK:          Index:
 // CHECK:          Name: .rodata.str1.1

 // CHECK-NEXT:     AddressAlignment: 1
 // CHECK-NEXT:     EntrySize: 8
 // CHECK-NEXT:   }
+// CHECK:        Section {
+// CHECK:          Index:
+// CHECK:          Name: .enormous_sh_entsize
+// CHECK-NEXT:     Type: SHT_PROGBITS
+// CHECK-NEXT:     Flags [
+// CHECK-NEXT:       SHF_MERGE
+// CHECK-NEXT:     ]
+// CHECK-NEXT:     Address:
+// CHECK-NEXT:     Offset:
+// CHECK-NEXT:     Size:
+// CHECK-NEXT:     Link:
+// CHECK-NEXT:     Info:
+// CHECK-NEXT:     AddressAlignment:
+// CHECK-NEXT:     EntrySize: 4294967296
+// CHECK-NEXT:   }