[ELF] - Linkerscript: accept integer values for PHDRS types.

[grimar]

Summary

Found that in the wild. Both gold and ld accepts integers instead of named constants
for PHDRS. For example older OpenBSD code had:
(https://lab.knightsofnii.com/kristaba/openbsd/blob/4a75b1afc24240f0320911070f95ddf644b8cac7/sys/arch/amd64/conf/kern.ldscript)

PHDRS
{
....
	openbsd_randomize 0x65a3dbe6; /* PT_OPENBSD_RANDOMIZE */
}

Patch adds support for that.

[ruiu]

ELF/LinkerScript.cpp

1727–1728

Just return Ret here.

if (readInteger(Tok, Ret))
  return Ret;

test/ELF/linkerscript/phdrs.s

52

I don't see a reason to have three test cases here. One pattern should suffice.

[grimar]

• Addressed review comments.

ELF/LinkerScript.cpp

1727–1728

readInteger() takes uint64, so looks better to have Val also.

test/ELF/linkerscript/phdrs.s

52

Ok.

[ruiu]

LGTM

ELF/LinkerScript.cpp

1709

Add a comment.

// Read a program header type name. The next token must be a
// name of a program header type or a constant (e.g. "0x3").

ELF/LinkerScript.cpp

if (Tok.empty()) {
       setError("section header name is empty");
       break;
     }
     Phdrs.push_back(Tok);
   }
   return Phdrs;
 }
 
 unsigned ScriptParser::readPhdrType() {
   StringRef Tok = next();
+  uint64_t Val;
+  if (readInteger(Tok, Val))
+    return Val;
+
   unsigned Ret = StringSwitch<unsigned>(Tok)
                      .Case("PT_NULL", PT_NULL)
                      .Case("PT_LOAD", PT_LOAD)
                      .Case("PT_DYNAMIC", PT_DYNAMIC)
                      .Case("PT_INTERP", PT_INTERP)
                      .Case("PT_NOTE", PT_NOTE)
                      .Case("PT_SHLIB", PT_SHLIB)
                      .Case("PT_PHDR", PT_PHDR)
                      .Case("PT_TLS", PT_TLS)
                      .Case("PT_GNU_EH_FRAME", PT_GNU_EH_FRAME)
                      .Case("PT_GNU_STACK", PT_GNU_STACK)
                      .Case("PT_GNU_RELRO", PT_GNU_RELRO)
                      .Default(-1);
 
   if (Ret == (unsigned)-1) {
     setError("invalid program header type: " + Tok);
     return PT_NULL;
   }
   return Ret;
 }
 
 void ScriptParser::readVersionDeclaration(StringRef VerStr) {

test/ELF/linkerscript/phdrs.s

 # AT-NEXT:      FileSize: 521
 # AT-NEXT:      MemSize: 521
 # AT-NEXT:      Flags [ (0x7)
 # AT-NEXT:        PF_R (0x4)
 # AT-NEXT:        PF_W (0x2)
 # AT-NEXT:        PF_X (0x1)
 # AT-NEXT:      ]
 
+## Check the numetic values for PHDRS.
+# RUN: echo "PHDRS {text PT_LOAD FILEHDR PHDRS; foo 0x11223344; } \
+# RUN:       SECTIONS { . = SIZEOF_HEADERS; .foo : { *(.*) } : text : foo}" > %t1.script
+# RUN: ld.lld -o %t2 --script %t1.script %t
+# RUN: llvm-readobj -program-headers %t2 | FileCheck --check-prefix=INT-PHDRS %s
+
+# INT-PHDRS:      ProgramHeaders [
+# INT-PHDRS:        ProgramHeader {
+# INT-PHDRS:           Type:  (0x11223344)
+# INT-PHDRS-NEXT:      Offset: 0xB0
+# INT-PHDRS-NEXT:      VirtualAddress: 0xB0
+# INT-PHDRS-NEXT:      PhysicalAddress: 0xB0
+# INT-PHDRS-NEXT:      FileSize: 9
+# INT-PHDRS-NEXT:      MemSize: 9
+# INT-PHDRS-NEXT:      Flags [
+# INT-PHDRS-NEXT:        PF_R
+# INT-PHDRS-NEXT:        PF_W
+# INT-PHDRS-NEXT:        PF_X
+# INT-PHDRS-NEXT:      ]
+# INT-PHDRS-NEXT:      Alignment: 4
+# INT-PHDRS-NEXT:    }
+# INT-PHDRS-NEXT:  ]
+
 .global _start
 _start:
  nop
 
 .section .foo.1,"a"
 foo1:
  .long 0
 
 .section .foo.2,"aw"
 foo2:
  .long 0