[llvm-readobj] - Teach readobj to print PT_OPENBSD_RANDOMIZE/PT_OPENBSD_WXNEEDED headers.

[grimar]

Summary

These are OpenBSD specific program headers and
currently we support them in LLD.

Description of headers (just in case) available here:
http://man.openbsd.org/OpenBSD-current/man5/elf.5

OpenBSD commits were:
For PT_OPENBSD_RANDOMIZE:
https://github.com/openbsd/src/commit/c494713c450d98da3f2e1451ee8c7fb675a7c461
For PT_OPENBSD_WXNEEDED:
https://github.com/openbsd/src/commit/2a5a8fc7e30928c2cff57cfe5fb491c90d8478ad

[emaste]

For reference I have now also added them to ELF Tool Chain's readelf in r3496.

tools/llvm-readobj/ELFDumper.cpp

1157–1160

The grouping seems a bit odd in this switch?

[davide]

test/tools/llvm-readobj/program-headers.test

9

You should add a comment explaining how you're generating this code, so that if we need to regenerate in the future we don't have to randomly guess.

154

Remove the (0x4), here and in other parts of the patch.

tools/llvm-readobj/ELFDumper.cpp

1157–1160

Agree.

[grimar]

• Addressed review comments.

test/tools/llvm-readobj/program-headers.test

9

Done.

154

Ok, though it is not consistent with other places in this file. I also removed all values checking, as
intention of testcase is to check string name of PHDR and nothing else.

tools/llvm-readobj/ELFDumper.cpp

1157–1160

It is grouped (and sorted) at the same way as done in ELF.h:

PT_NULL    = 0, // Unused segment.
PT_LOAD    = 1, // Loadable segment.
PT_DYNAMIC = 2, // Dynamic linking information.
PT_INTERP  = 3, // Interpreter pathname.
PT_NOTE    = 4, // Auxiliary information.
PT_SHLIB   = 5, // Reserved.
PT_PHDR    = 6, // The program header table itself.
PT_TLS     = 7, // The thread-local storage template.
PT_LOOS    = 0x60000000, // Lowest operating system-specific pt entry type.
PT_HIOS    = 0x6fffffff, // Highest operating system-specific pt entry type.
PT_LOPROC  = 0x70000000, // Lowest processor-specific program hdr entry type.
PT_HIPROC  = 0x7fffffff, // Highest processor-specific program hdr entry type.

// x86-64 program header types.
// These all contain stack unwind tables.
PT_GNU_EH_FRAME  = 0x6474e550,
PT_SUNW_EH_FRAME = 0x6474e550,
PT_SUNW_UNWIND   = 0x6464e550,

PT_GNU_STACK = 0x6474e551, // Indicates stack executability.
PT_GNU_RELRO = 0x6474e552, // Read-only after relocation.

PT_OPENBSD_RANDOMIZE = 0x65a3dbe6, // Fill with random data.
PT_OPENBSD_WXNEEDED  = 0x65a3dbe7, // Program does W^X violations.

[davide]

LGTM modulo nit.

test/tools/llvm-readobj/program-headers.test

33

test.s is an empty file.
linker.script:

154

cool.

test/tools/llvm-readobj/program-headers.test

 RUN: llvm-readobj -program-headers %p/../../Object/Inputs/program-headers.elf-i386 \
 RUN:     | FileCheck %s -check-prefix ELF-I386
 RUN: llvm-readobj -program-headers %p/../../Object/Inputs/program-headers.elf-x86-64 \
 RUN:     | FileCheck %s -check-prefix ELF-X86-64
 RUN: llvm-readobj -program-headers %p/../../Object/Inputs/program-headers.mips \
 RUN:     | FileCheck %s -check-prefix ELF-MIPS
 RUN: llvm-readobj -program-headers %p/../../Object/Inputs/program-headers.mips64 \
 RUN:     | FileCheck %s -check-prefix ELF-MIPS64
+RUN: llvm-readobj -program-headers %p/../../Object/Inputs/openbsd-phdrs.elf-x86-64 \
+RUN:     | FileCheck %s -check-prefix OPENBSD-X86-64
 
 ELF-I386:      ProgramHeaders [
 ELF-I386-NEXT:   ProgramHeader {
 ELF-I386-NEXT:     Type: PT_LOAD (0x1)
 ELF-I386-NEXT:     Offset: 0x0
 ELF-I386-NEXT:     VirtualAddress: 0x8048000
 ELF-I386-NEXT:     PhysicalAddress: 0x8048000
 ELF-I386-NEXT:     FileSize: 308
 ELF-I386-NEXT:     MemSize: 308
 ELF-I386-NEXT:     Flags [ (0x5)
 ELF-I386-NEXT:       PF_R (0x4)
 ELF-I386-NEXT:       PF_X (0x1)
 ELF-I386-NEXT:     ]
 ELF-I386-NEXT:     Alignment: 4096
 ELF-I386-NEXT:   }
 ELF-I386-NEXT:   ProgramHeader {
 ELF-I386-NEXT:     Type: PT_GNU_STACK (0x6474E551)
 ELF-I386-NEXT:     Offset: 0x0
 ELF-I386-NEXT:     VirtualAddress: 0x0
 ELF-I386-NEXT:     PhysicalAddress: 0x0
 ELF-I386-NEXT:     FileSize: 0
 ELF-I386-NEXT:     MemSize: 0
 ELF-I386-NEXT:     Flags [ (0x6)
 ELF-I386-NEXT:       PF_R (0x4)
 ELF-I386-NEXT:       PF_W (0x2)
 ELF-I386-NEXT:     ]
 ELF-I386-NEXT:     Alignment: 4
 ELF-I386-NEXT:   }
 ELF-I386-NEXT: ]
 
 ELF-X86-64:      ProgramHeaders [

 ELF-MIPS64-NEXT:     MemSize: 136
 ELF-MIPS64-NEXT:     Flags [ (0x5)
 ELF-MIPS64-NEXT:       PF_R (0x4)
 ELF-MIPS64-NEXT:       PF_X (0x1)
 ELF-MIPS64-NEXT:     ]
 ELF-MIPS64-NEXT:     Alignment: 65536
 ELF-MIPS64-NEXT:   }
 ELF-MIPS64-NEXT: ]
+
+OPENBSD-X86-64:      ProgramHeaders [
+OPENBSD-X86-64:        ProgramHeader {
+OPENBSD-X86-64:          Type:  PT_OPENBSD_RANDOMIZE
+OPENBSD-X86-64-NEXT:     Offset: 0xB4
+OPENBSD-X86-64-NEXT:     VirtualAddress: 0xB4
+OPENBSD-X86-64-NEXT:     PhysicalAddress: 0xB4
+OPENBSD-X86-64-NEXT:     FileSize: 8
+OPENBSD-X86-64-NEXT:     MemSize: 8
+OPENBSD-X86-64-NEXT:     Flags [ (0x4)
+OPENBSD-X86-64-NEXT:       PF_R (0x4)
+OPENBSD-X86-64-NEXT:     ]
+OPENBSD-X86-64-NEXT:     Alignment: 1
+OPENBSD-X86-64-NEXT:   }
+OPENBSD-X86-64-NEXT:   ProgramHeader {
+OPENBSD-X86-64-NEXT:     Type:  PT_OPENBSD_WXNEEDED
+OPENBSD-X86-64-NEXT:     Offset: 0x0
+OPENBSD-X86-64-NEXT:     VirtualAddress: 0x0
+OPENBSD-X86-64-NEXT:     PhysicalAddress: 0x0
+OPENBSD-X86-64-NEXT:     FileSize: 0
+OPENBSD-X86-64-NEXT:     MemSize: 0
+OPENBSD-X86-64-NEXT:     Flags [ (0x4)
+OPENBSD-X86-64-NEXT:       PF_R (0x4)
+OPENBSD-X86-64-NEXT:     ]
+OPENBSD-X86-64-NEXT:     Alignment: 0
+OPENBSD-X86-64-NEXT:   }

tools/llvm-readobj/ELFDumper.cpp

static const char *getElfSegmentType(unsigned Arch, unsigned Type) {
   LLVM_READOBJ_ENUM_CASE(ELF, PT_PHDR   );
   LLVM_READOBJ_ENUM_CASE(ELF, PT_TLS    );
 
   LLVM_READOBJ_ENUM_CASE(ELF, PT_GNU_EH_FRAME);
   LLVM_READOBJ_ENUM_CASE(ELF, PT_SUNW_UNWIND);
 
   LLVM_READOBJ_ENUM_CASE(ELF, PT_GNU_STACK);
   LLVM_READOBJ_ENUM_CASE(ELF, PT_GNU_RELRO);
+
+  LLVM_READOBJ_ENUM_CASE(ELF, PT_OPENBSD_RANDOMIZE);
+  LLVM_READOBJ_ENUM_CASE(ELF, PT_OPENBSD_WXNEEDED);
+
   default: return "";
   }
 }
 
 static std::string getElfPtType(unsigned Arch, unsigned Type) {
   switch (Type) {
     LLVM_READOBJ_PHDR_ENUM(ELF, PT_NULL)
     LLVM_READOBJ_PHDR_ENUM(ELF, PT_LOAD)