[ELF] - Round executable PT_LOAD to page size and pad it with traps

[grimar]

Summary

This is PR33819,

Patch attempts to simplify outdated D33630.

[grimar]

• Rebased.
• Simplified.

[grimar]

r309829

[joerg]

I'm not sure I want anything like this unconditionally. It is going to waste quite a bit of space, i.e. 2KB per executable and shared library sums up.

[grimar]

In D35680#830334, @joerg wrote:

I'm not sure I want anything like this unconditionally. It is going to waste quite a bit of space, i.e. 2KB per executable and shared library sums up.

Just in case: this patch was abandoned, D33630 was landed. It do something about the same though, but probably more correct to discuss in its thread.

ELF/LinkerScript.h

public:
 
   // Parsed linker script configurations are set to this struct.
   ScriptConfiguration Opt;
 };
 
 extern LinkerScript *Script;
 
 } // end namespace elf
+
+void fill(uint8_t *Buf, size_t Size, uint32_t Filler);
+
 } // end namespace lld
 
 #endif // LLD_ELF_LINKER_SCRIPT_H

ELF/LinkerScript.cpp

 }
 
 bool OutputSectionCommand::classof(const BaseCommand *C) {
   return C->Kind == OutputSectionKind;
 }
 
 // Fill [Buf, Buf + Size) with Filler.
 // This is used for linker script "=fillexp" command.
-static void fill(uint8_t *Buf, size_t Size, uint32_t Filler) {
+void lld::fill(uint8_t *Buf, size_t Size, uint32_t Filler) {
   size_t I = 0;
   for (; I + 4 < Size; I += 4)
     memcpy(Buf + I, &Filler, 4);
   memcpy(Buf + I, &Filler, Size - I);
 }
 
 bool InputSectionDescription::classof(const BaseCommand *C) {
   return C->Kind == InputSectionKind;

ELF/Writer.cpp

private:
   void removeEmptyPTLoad();
   void addPtArmExid(std::vector<PhdrEntry *> &Phdrs);
   void assignFileOffsets();
   void assignFileOffsetsBinary();
   void setPhdrs();
   void fixSectionAlignments();
   void fixPredefinedSymbols();
   void openFile();
+  void writeTrapInstr();
   void writeHeader();
   void writeSections();
   void writeSectionsBinary();
   void writeBuildId();
 
   std::unique_ptr<FileOutputBuffer> Buffer;
 
   OutputSectionFactory Factory;
template <class ELFT> void Writer<ELFT>::run() {
   if (ErrorCount)
     return;
   // Write the result down to a file.
   openFile();
   if (ErrorCount)
     return;
 
   if (!Config->OFormatBinary) {
+    writeTrapInstr();
     writeHeader();
     writeSections();
   } else {
     writeSectionsBinary();
   }
 
   // Backfill .note.gnu.build-id section content. This is done at last
   // because the content is usually a hash value of the entire output file.
template <class ELFT> void Writer<ELFT>::assignFileOffsetsBinary() {
   for (OutputSectionCommand *Cmd : OutputSectionCommands) {
     OutputSection *Sec = Cmd->Sec;
     if (Sec->Flags & SHF_ALLOC)
       Off = setOffset(Sec, Off);
   }
   FileSize = alignTo(Off, Config->Wordsize);
 }
 
+static std::vector<PhdrEntry *> getExecLoads(ArrayRef<PhdrEntry *> V) {
+  std::vector<PhdrEntry *> Ret;
+  for (PhdrEntry *Load : V)
+    if (Load->p_type == PT_LOAD && Load->p_flags & PF_X)
+      Ret.push_back(Load);
+  return Ret;
+}
+
 // Assign file offsets to output sections.
 template <class ELFT> void Writer<ELFT>::assignFileOffsets() {
   uint64_t Off = 0;
   Off = setOffset(Out::ElfHeader, Off);
   Off = setOffset(Out::ProgramHeaders, Off);
 
-  for (OutputSectionCommand *Cmd : OutputSectionCommands)
+  std::vector<PhdrEntry *> ExecLoads = getExecLoads(Phdrs);
+  OutputSection *LastExec =
+      ExecLoads.empty() ? nullptr : ExecLoads.back()->Last;
+  for (OutputSectionCommand *Cmd : OutputSectionCommands) {
     Off = setOffset(Cmd->Sec, Off);
 
+    // If no linker script is involved and allocatable section is the last in
+    // executable segment, that means we want to ensure segment contains only
+    // valid instructions and hence we align next section's offset to avoid
+    // loading of non-allocatable content. We will fill gap with trap op codes.
+    if (!Script->Opt.HasSections)
+      if (Cmd->Sec == LastExec)
+        Off = alignTo(Off, Target->PageSize);
+  }
+
   SectionHeaderOff = alignTo(Off, Config->Wordsize);
   FileSize =
       SectionHeaderOff + (OutputSectionCommands.size() + 1) * sizeof(Elf_Shdr);
 }
 
 // Finalize the program headers. We call this function after we assign
 // file offsets and VAs to all sections.
 template <class ELFT> void Writer<ELFT>::setPhdrs() {
template <class ELFT> void Writer<ELFT>::writeSectionsBinary() {
   uint8_t *Buf = Buffer->getBufferStart();
   for (OutputSectionCommand *Cmd : OutputSectionCommands) {
     OutputSection *Sec = Cmd->Sec;
     if (Sec->Flags & SHF_ALLOC)
       Cmd->writeTo<ELFT>(Buf + Sec->Offset);
   }
 }
 
+static void fillPage(uint8_t *Buf, uint64_t Offset, uint32_t Filler) {
+  uint64_t Begin = alignDown(Offset, Target->PageSize);
+  uint64_t End = alignTo(Offset, Target->PageSize);
+  fill(Buf + Begin, End - Begin, Filler);
+}
+
+template <class ELFT> void Writer<ELFT>::writeTrapInstr() {
+  // FIXME: do the same for case when sections present.
+  if (Script->Opt.HasSections)
+    return;
+
+  uint8_t *Buf = Buffer->getBufferStart();
+  for (PhdrEntry *Load : getExecLoads(Phdrs)) {
+    // We only fill the first and the last page of the segment because the
+    // middle part will be overwritten by output sections.
+    fillPage(Buf, Load->p_offset, Target->TrapInstr);
+    fillPage(Buf, Load->p_offset + Load->p_filesz, Target->TrapInstr);
+  }
+
+  // Round up the file size of the last segment to the page boundary if it is
+  // an executable segment to ensure that other other tools don't accidentally
+  // trim the instruction padding (e.g. when stripping the file).
+  auto It = llvm::find_if(llvm::reverse(Phdrs), [](PhdrEntry *Phdr) {
+    return Phdr->p_type == PT_LOAD;
+  });
+  if (It != Phdrs.rend() && (*It)->p_flags & PF_X)
+    (*It)->p_filesz = alignTo((*It)->p_filesz, Target->PageSize);
+}
+
 // Write section contents to a mmap'ed file.
 template <class ELFT> void Writer<ELFT>::writeSections() {
   uint8_t *Buf = Buffer->getBufferStart();
 
   // PPC64 needs to process relocations in the .opd section
   // before processing relocations in code-containing sections.
   if (auto *OpdCmd = findSectionCommand(".opd")) {
     Out::Opd = OpdCmd->Sec;

test/ELF/avoid-empty-program-headers.s

 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Alignment: 4096
 // CHECK-NEXT:   }
 // CHECK-NEXT:   ProgramHeader {
 // CHECK-NEXT:     Type: PT_LOAD (0x1)
 // CHECK-NEXT:     Offset: 0x1000
 // CHECK-NEXT:     VirtualAddress: 0x201000
 // CHECK-NEXT:     PhysicalAddress: 0x201000
-// CHECK-NEXT:     FileSize: 1
+// CHECK-NEXT:     FileSize: 4096
 // CHECK-NEXT:     MemSize: 1
 // CHECK-NEXT:     Flags [ (0x5)
 // CHECK-NEXT:       PF_R (0x4)
 // CHECK-NEXT:       PF_X (0x1)
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Alignment: 4096
 // CHECK-NEXT:   }
 // CHECK-NEXT:   ProgramHeader {
 // CHECK-NEXT:     Type: PT_TLS (0x7)
-// CHECK-NEXT:     Offset: 0x1001
+// CHECK-NEXT:     Offset: 0x2000
 // CHECK-NEXT:     VirtualAddress: 0x201001
 // CHECK-NEXT:     PhysicalAddress: 0x201001
 // CHECK-NEXT:     FileSize: 0
 // CHECK-NEXT:     MemSize: 4
 // CHECK-NEXT:     Flags [ (0x4)
 // CHECK-NEXT:       PF_R (0x4)
 // CHECK-NEXT:     ]
 // CHECK-NEXT:     Alignment: 1

test/ELF/basic-aarch64.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_AARCH64 (0xB7)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: [[ENTRY:0x[0-9A-F]+]]
 # CHECK-NEXT:   ProgramHeaderOffset: 0x40
-# CHECK-NEXT:   SectionHeaderOffset: 0x10098
+# CHECK-NEXT:   SectionHeaderOffset: 0x11088
 # CHECK-NEXT:   Flags [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 64
 # CHECK-NEXT:   ProgramHeaderEntrySize: 56
 # CHECK-NEXT:   ProgramHeaderCount: 4
 # CHECK-NEXT:   SectionHeaderEntrySize: 64
 # CHECK-NEXT:   SectionHeaderCount: 6
 # CHECK-NEXT:   StringTableSectionIndex: 4

 # CHECK-NEXT:     Index: 2
 # CHECK-NEXT:     Name: .comment
 # CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
 # CHECK-NEXT:     Flags [ (0x30)
 # CHECK-NEXT:       SHF_MERGE (0x10)
 # CHECK-NEXT:       SHF_STRINGS (0x20)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1000C
+# CHECK-NEXT:     Offset: 0x11000
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 3
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB (0x2)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x10018
+# CHECK-NEXT:     Offset: 0x11008
 # CHECK-NEXT:     Size: 72
 # CHECK-NEXT:     Link: 5
 # CHECK-NEXT:     Info: 2
 # CHECK-NEXT:     AddressAlignment: 8
 # CHECK-NEXT:     EntrySize: 24
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 4
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x10060
+# CHECK-NEXT:     Offset: 0x11050
 # CHECK-NEXT:     Size: 42
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 5
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1008A
+# CHECK-NEXT:     Offset: 0x1107A
 # CHECK-NEXT:     Size: 13
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 # CHECK-NEXT: Symbols [

 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 65536
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {
 # CHECK-NEXT:     Type: PT_LOAD (0x1)
 # CHECK-NEXT:     Offset: 0x1000
 # CHECK-NEXT:     VirtualAddress: 0x20000
 # CHECK-NEXT:     PhysicalAddress: 0x20000
-# CHECK-NEXT:     FileSize: 12
+# CHECK-NEXT:     FileSize: 4096
 # CHECK-NEXT:     MemSize: 12
 # CHECK-NEXT:     Flags [ (0x5)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:       PF_X (0x1)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 65536
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {

test/ELF/basic-sparcv9.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_SPARCV9 (0x2B)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: [[ENTRY:0x[0-9A-F]+]]
 # CHECK-NEXT:   ProgramHeaderOffset: 0x40
-# CHECK-NEXT:   SectionHeaderOffset: 0x100080
+# CHECK-NEXT:   SectionHeaderOffset: 0x102070
 # CHECK-NEXT:   Flags [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 64
 # CHECK-NEXT:   ProgramHeaderEntrySize: 56
 # CHECK-NEXT:   ProgramHeaderCount: 4
 # CHECK-NEXT:   SectionHeaderEntrySize: 64
 # CHECK-NEXT:   SectionHeaderCount: 6
 # CHECK-NEXT:   StringTableSectionIndex: 4

 # CHECK-NEXT:     Index: 2
 # CHECK-NEXT:     Name: .comment
 # CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
 # CHECK-NEXT:     Flags [ (0x30)
 # CHECK-NEXT:       SHF_MERGE (0x10)
 # CHECK-NEXT:       SHF_STRINGS (0x20)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x10000C
+# CHECK-NEXT:     Offset: 0x102000
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 3
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB (0x2)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x100018
+# CHECK-NEXT:     Offset: 0x102008
 # CHECK-NEXT:     Size: 48
 # CHECK-NEXT:     Link: 5
 # CHECK-NEXT:     Info: 1
 # CHECK-NEXT:     AddressAlignment: 8
 # CHECK-NEXT:     EntrySize: 24
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 4
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x100048
+# CHECK-NEXT:     Offset: 0x102038
 # CHECK-NEXT:     Size: 42
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 5
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x100072
+# CHECK-NEXT:     Offset: 0x102062
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 # CHECK-NEXT: Symbols [

 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 1048576
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {
 # CHECK-NEXT:     Type: PT_LOAD (0x1)
 # CHECK-NEXT:     Offset: 0x100000
 # CHECK-NEXT:     VirtualAddress: 0x200000
 # CHECK-NEXT:     PhysicalAddress: 0x200000
-# CHECK-NEXT:     FileSize: 12
+# CHECK-NEXT:     FileSize: 8192
 # CHECK-NEXT:     MemSize: 12
 # CHECK-NEXT:     Flags [ (0x5)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:       PF_X (0x1)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 1048576
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {

test/ELF/basic.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_X86_64 (0x3E)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: [[ENTRY:0x[0-9A-F]+]]
 # CHECK-NEXT:   ProgramHeaderOffset: 0x40
-# CHECK-NEXT:   SectionHeaderOffset: 0x1080
+# CHECK-NEXT:   SectionHeaderOffset: 0x2070
 # CHECK-NEXT:   Flags [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 64
 # CHECK-NEXT:   ProgramHeaderEntrySize: 56
 # CHECK-NEXT:   ProgramHeaderCount: 4
 # CHECK-NEXT:   SectionHeaderEntrySize: 64
 # CHECK-NEXT:   SectionHeaderCount: 6
 # CHECK-NEXT:   StringTableSectionIndex: 4

 # CHECK-NEXT:     Index: 2
 # CHECK-NEXT:     Name: .comment
 # CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
 # CHECK-NEXT:     Flags [ (0x30)
 # CHECK-NEXT:       SHF_MERGE (0x10)
 # CHECK-NEXT:       SHF_STRINGS (0x20)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1010
+# CHECK-NEXT:     Offset: 0x2000
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 3
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB (0x2)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1018
+# CHECK-NEXT:     Offset: 0x2008
 # CHECK-NEXT:     Size: 48
 # CHECK-NEXT:     Link: 5
 # CHECK-NEXT:     Info: 1
 # CHECK-NEXT:     AddressAlignment: 8
 # CHECK-NEXT:     EntrySize: 24
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 4
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1048
+# CHECK-NEXT:     Offset: 0x2038
 # CHECK-NEXT:     Size: 42
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 5
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1072
+# CHECK-NEXT:     Offset: 0x2062
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 # CHECK-NEXT: Symbols [

 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 4096
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {
 # CHECK-NEXT:     Type: PT_LOAD (0x1)
 # CHECK-NEXT:     Offset: 0x1000
 # CHECK-NEXT:     VirtualAddress: 0x201000
 # CHECK-NEXT:     PhysicalAddress: 0x201000
-# CHECK-NEXT:     FileSize: 16
+# CHECK-NEXT:     FileSize: 4096
 # CHECK-NEXT:     MemSize: 16
 # CHECK-NEXT:     Flags [ (0x5)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:       PF_X (0x1)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 4096
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {

test/ELF/basic32.s

 # CHECK-NEXT:     ABIVersion: 0
 # CHECK-NEXT:     Unused: (00 00 00 00 00 00 00)
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Type: Executable (0x2)
 # CHECK-NEXT:   Machine: EM_386 (0x3)
 # CHECK-NEXT:   Version: 1
 # CHECK-NEXT:   Entry: 0x11000
 # CHECK-NEXT:   ProgramHeaderOffset: 0x34
-# CHECK-NEXT:   SectionHeaderOffset: 0x1068
+# CHECK-NEXT:   SectionHeaderOffset: 0x205C
 # CHECK-NEXT:   Flags [ (0x0)
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 52
 # CHECK-NEXT:   ProgramHeaderEntrySize: 32
 # CHECK-NEXT:   ProgramHeaderCount: 4
 # CHECK-NEXT:   SectionHeaderEntrySize: 40
 # CHECK-NEXT:   SectionHeaderCount: 6
 # CHECK-NEXT:   StringTableSectionIndex: 4

 # CHECK-NEXT:     Index: 2
 # CHECK-NEXT:     Name: .comment
 # CHECK-NEXT:     Type: SHT_PROGBITS (0x1)
 # CHECK-NEXT:     Flags [ (0x30)
 # CHECK-NEXT:       SHF_MERGE (0x10)
 # CHECK-NEXT:       SHF_STRINGS (0x20)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x100C
+# CHECK-NEXT:     Offset: 0x2000
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 3
 # CHECK-NEXT:     Name: .symtab
 # CHECK-NEXT:     Type: SHT_SYMTAB
 # CHECK-NEXT:     Flags [
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1014
+# CHECK-NEXT:     Offset: 0x2008
 # CHECK-NEXT:     Size: 32
 # CHECK-NEXT:     Link: 5
 # CHECK-NEXT:     Info: 1
 # CHECK-NEXT:     AddressAlignment: 4
 # CHECK-NEXT:     EntrySize: 16
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 4
 # CHECK-NEXT:     Name: .shstrtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x1034
+# CHECK-NEXT:     Offset: 0x2028
 # CHECK-NEXT:     Size: 42
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT:   Section {
 # CHECK-NEXT:     Index: 5
 # CHECK-NEXT:     Name: .strtab
 # CHECK-NEXT:     Type: SHT_STRTAB (0x3)
 # CHECK-NEXT:     Flags [ (0x0)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Address: 0x0
-# CHECK-NEXT:     Offset: 0x105E
+# CHECK-NEXT:     Offset: 0x2052
 # CHECK-NEXT:     Size: 8
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
 # CHECK-NEXT:     AddressAlignment: 1
 # CHECK-NEXT:     EntrySize: 0
 # CHECK-NEXT:   }
 # CHECK-NEXT: ]
 # CHECK-NEXT: ProgramHeaders [

 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 4096
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {
 # CHECK-NEXT:     Type: PT_LOAD (0x1)
 # CHECK-NEXT:     Offset: 0x1000
 # CHECK-NEXT:     VirtualAddress: 0x11000
 # CHECK-NEXT:     PhysicalAddress: 0x11000
-# CHECK-NEXT:     FileSize: 12
+# CHECK-NEXT:     FileSize: 4096
 # CHECK-NEXT:     MemSize: 12
 # CHECK-NEXT:     Flags [ (0x5)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:       PF_X (0x1)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 4096
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {

test/ELF/build-id.s

_start:
   nop
 
 .section .note.test, "a", @note
    .quad 42
 
 # DEFAULT:      Contents of section .note.test:
 # DEFAULT:      Contents of section .note.gnu.build-id:
 # DEFAULT-NEXT: 04000000 08000000 03000000 474e5500  ............GNU.
-# DEFAULT-NEXT: fd36edb1 f6ff02af
+# DEFAULT-NEXT: b0148597 ba5eb7e9
 
 # MD5:      Contents of section .note.gnu.build-id:
 # MD5-NEXT: 04000000 10000000 03000000 474e5500  ............GNU.
 # MD5-NEXT: fc
 
 # SHA1:      Contents of section .note.gnu.build-id:
 # SHA1-NEXT: 04000000 14000000 03000000 474e5500  ............GNU.
-# SHA1-NEXT: 55b1eedb 03b588e1 09987d1d e9a79be7
+# SHA1-NEXT: 2f716666 fe3668fe 370a02a1 579c3eb2
 
 # UUID:      Contents of section .note.gnu.build-id:
 # UUID-NEXT: 04000000 10000000 03000000 474e5500  ............GNU.
 
 # HEX:      Contents of section .note.gnu.build-id:
 # HEX-NEXT: 04000000 04000000 03000000 474e5500  ............GNU.
 # HEX-NEXT: 12345678
 
 # NONE-NOT: Contents of section .note.gnu.build-id:

test/ELF/image-base.s

 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 4096
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {
 # CHECK-NEXT:     Type: PT_LOAD (0x1)
 # CHECK-NEXT:     Offset: 0x1000
 # CHECK-NEXT:     VirtualAddress: 0x1001000
 # CHECK-NEXT:     PhysicalAddress: 0x1001000
-# CHECK-NEXT:     FileSize: 1
+# CHECK-NEXT:     FileSize: 4096
 # CHECK-NEXT:     MemSize: 1
 # CHECK-NEXT:     Flags [ (0x5)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:       PF_X (0x1)
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 4096
 # CHECK-NEXT:   }
 # CHECK-NEXT:   ProgramHeader {

test/ELF/relocatable.s

 # CHECKEXE-NEXT:      ABIVersion: 0
 # CHECKEXE-NEXT:      Unused: (00 00 00 00 00 00 00)
 # CHECKEXE-NEXT:    }
 # CHECKEXE-NEXT:    Type: Executable
 # CHECKEXE-NEXT:    Machine: EM_X86_64
 # CHECKEXE-NEXT:    Version: 1
 # CHECKEXE-NEXT:    Entry: 0x201000
 # CHECKEXE-NEXT:    ProgramHeaderOffset: 0x40
-# CHECKEXE-NEXT:    SectionHeaderOffset: 0x11F8
+# CHECKEXE-NEXT:    SectionHeaderOffset: 0x21A0
 # CHECKEXE-NEXT:    Flags [
 # CHECKEXE-NEXT:    ]
 # CHECKEXE-NEXT:    HeaderSize: 64
 # CHECKEXE-NEXT:    ProgramHeaderEntrySize: 56
 # CHECKEXE-NEXT:    ProgramHeaderCount: 5
 # CHECKEXE-NEXT:    SectionHeaderEntrySize: 64
 # CHECKEXE-NEXT:    SectionHeaderCount: 7
 # CHECKEXE-NEXT:    StringTableSectionIndex: 5