[ELF] - Teach LLD to recognize PT_OPENBSD_BOOTDATA

[grimar]

Summary

Minor patch to fix PR31288

OpenBSD commit:
https://github.com/openbsd/src/commit/d39116912b9536bd77326260dc5c6e593fd4ee24

[ruiu]

ELF/LinkerScript.cpp

1862 ↗

(On Diff #80421)

Sort.

test/ELF/linkerscript/openbsd-bootdata.s

2–4 ↗

(On Diff #80421)

Why did you need .text?

Also, please do not use line continuations (\) in echo. It makes output messages hard to read when this test fails.

11–20 ↗

(On Diff #80421)

Remove these lines because we are not interested in testing them.

[grimar]

ELF/LinkerScript.cpp

1862 ↗

(On Diff #80421)

Sorted by value, like others entries.

[ruiu]

ELF/LinkerScript.cpp

1862 ↗

(On Diff #80421)

But why? Probably nobody memorizes these numbers.

[grimar]

ELF/LinkerScript.cpp

1862 ↗

(On Diff #80421)

Hmmm. For consistency. Whole StringSwitch is sorted by values.
Also them are sorted in ELF.h in the same way and it is comfortable to compare missings if needed.

[ruiu]

ELF/LinkerScript.cpp

1862 ↗

(On Diff #80421)

Consistency with ELF.h may make sense, though I'm tempted to sort them here. OK in either way.

[grimar]

• Addressed review comments.

test/ELF/linkerscript/openbsd-bootdata.s

2–4 ↗

(On Diff #80421)

Right, I think i do not need anything except what is in current diff, we can just check that lld creates header.

[ruiu]

Now that I wonder why we need one file per each program header type. Can you consolidate?

[grimar]

In D27458#614630, @ruiu wrote:

Now that I wonder why we need one file per each program header type. Can you consolidate?

You mean combine testcases for OpenBSD into single file ? Probably yes, I'll try tomorrow.

[ruiu]

LGTM. Let's do cleanup in a followup patch.

[grimar]

In D27458#614665, @ruiu wrote:

LGTM. Let's do cleanup in a followup patch.

Thanks. By the way, after looking closer, openbsd-randomize.s (PT_OPENBSD_RANDOMIZE) and openbsd-wxneeded.s (PT_OPENBSD_WXNEEDED) are a bit different form this.
Both of them involve additional logic in LLD.

PT_OPENBSD_WXNEEDED relative to -z wxneeded,
PT_OPENBSD_RANDOMIZE is generated when we have ".openbsd.randomdata" section.
I would probably not combine their testcases.

May be we should just rename this testcase to openbsd-common-phdrs.s and use for all OpenBSD program headers that do not require any special logic ?

lld/trunk/ELF/LinkerScript.cpp

unsigned Ret = StringSwitch<unsigned>(Tok)
                      .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)
                      .Case("PT_OPENBSD_RANDOMIZE", PT_OPENBSD_RANDOMIZE)
                      .Case("PT_OPENBSD_WXNEEDED", PT_OPENBSD_WXNEEDED)
+                     .Case("PT_OPENBSD_BOOTDATA", PT_OPENBSD_BOOTDATA)
                      .Default(-1);
 
   if (Ret == (unsigned)-1) {
     setError("invalid program header type: " + Tok);
     return PT_NULL;
   }
   return Ret;
 }

lld/trunk/test/ELF/linkerscript/openbsd-bootdata.s

+# RUN: llvm-mc -filetype=obj -triple=i686-unknown-linux %s -o %t.o
+# RUN: echo "PHDRS { boot PT_OPENBSD_BOOTDATA; }" > %t.script
+# RUN: ld.lld --script %t.script %t.o -o %t
+# RUN: llvm-readobj --program-headers -s %t | FileCheck %s
+
+# CHECK:      ProgramHeader {
+# CHECK:        Type: PT_OPENBSD_BOOTDATA (0x65A41BE6)