[COFF, ARM64] Add initial relocation types

[compnerd]

Please add tests for the other relocation types.

[mgrang]

Added more relocations.
Could not find a test case for IMAGE_REL_ARM64_ADDR32NB.
I see that IMAGE_REL_ARM64_SECTION is generated only on Windows with dumpbin (and not on Linux with llvm-objdump). Does it make sense to limit this unit test only for Windows?

[rnk]

test/MC/AArch64/coff-relocations.ll

1 ↗

(On Diff #106788)

Use a .s test instead. You can probably run this file through llc, and then run llvm-mc on that to generate an object.

78 ↗

(On Diff #106788)

With a .s test, you won't need all this complex debug info to make SECREL and SECTION relocations, you can just directly use the .secrel and .secidx directives.

[mgrang]

@rnk Got it! Thanks. Will push an updated patch.

[mgrang]

Changed unit test to .s according to comments.
Unit tests for IMAGE_REL_ARM64_PAGEOFFSET_12A and IMAGE_REL_ARM64_PAGEOFFSET_12L not added as llvm-mc currently cannot parse the assembly for these. Here is my code for the above two relocations:

adrp x0, foo
add x0, x0, foo

This is the error I get:

error: expected compatible register, symbol or integer in range [0, 4095]
add x0, x0, foo
                  ^

[mstorsjo]

In D34857#810706, @mgrang wrote:

I see that IMAGE_REL_ARM64_SECTION is generated only on Windows with dumpbin (and not on Linux with llvm-objdump). Does it make sense to limit this unit test only for Windows?

I'd rather have a look at llvm-objdump and see if it can easily be fixed to show what you want.

In D34857#810748, @mgrang wrote:

Unit tests for IMAGE_REL_ARM64_PAGEOFFSET_12A and IMAGE_REL_ARM64_PAGEOFFSET_12L not added as llvm-mc currently cannot parse the assembly for these. Here is my code for the above two relocations:

adrp x0, foo
add x0, x0, foo

The correct syntax that llvm-mc should accept is this:

add x0, x0, :lo12:foo

IIRC this should also work with ldr/str:

ldr x0, [x0, :lo12:foo]

[mgrang]

Added test cases for all the implemented relocation types.

[mgrang]

In D34857#810769, @mstorsjo wrote:

In D34857#810706, @mgrang wrote:

I see that IMAGE_REL_ARM64_SECTION is generated only on Windows with dumpbin (and not on Linux with llvm-objdump). Does it make sense to limit this unit test only for Windows?

I'd rather have a look at llvm-objdump and see if it can easily be fixed to show what you want.

In D34857#810748, @mgrang wrote:

Unit tests for IMAGE_REL_ARM64_PAGEOFFSET_12A and IMAGE_REL_ARM64_PAGEOFFSET_12L not added as llvm-mc currently cannot parse the assembly for these. Here is my code for the above two relocations:

adrp x0, foo
add x0, x0, foo

The correct syntax that llvm-mc should accept is this:

add x0, x0, :lo12:foo

IIRC this should also work with ldr/str:

ldr x0, [x0, :lo12:foo]

Thanks @mstorsjo for pointing me to the correct assembly for add/ldr. My test cases now work for all the implemented relocation types.

[compnerd]

Please fix the relocation type before you commit this.

lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp

50–74

Use auto and clang-format.

66

Shouldn't this be IMAGE_REL_ARM64_SECREL?

67

Why no newline here? Can you make the newline spacing uniform?

test/MC/AArch64/coff-relocations.s

3

Don't think that you need the second RUN: here.

[mgrang]

Addressed comments.

[mgrang]

I have addressed comments, and my previous patch was accepted by @compnerd. So unless someone has any more comments I will go ahead and commit this.

test/MC/AArch64/coff-relocations.s

3

Without the second RUN, this line is reported as malformed. I checked that a lot of the other tests also use a similar format of multiple RUNs.

lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFObjectWriter.cpp

 } // end anonymous namespace
 
 unsigned
 AArch64WinCOFFObjectWriter::getRelocType(MCContext &Ctx,
                                          const MCValue &Target,
                                          const MCFixup &Fixup,
                                          bool IsCrossSection,
                                          const MCAsmBackend &MAB) const {
+  switch (static_cast<unsigned>(Fixup.getKind())) {
+  default: {
     const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
     report_fatal_error(Twine("unsupported relocation type: ") + Info.Name);
   }
+  case FK_Data_8:
+    return COFF::IMAGE_REL_ARM64_ADDR64;
+
+  case AArch64::fixup_aarch64_add_imm12:
+   return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12A;
+
+  case AArch64::fixup_aarch64_ldst_imm12_scale1:
+  case AArch64::fixup_aarch64_ldst_imm12_scale2:
+  case AArch64::fixup_aarch64_ldst_imm12_scale4:
+  case AArch64::fixup_aarch64_ldst_imm12_scale8:
+  case AArch64::fixup_aarch64_ldst_imm12_scale16:
+   return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12L;
+
+  case AArch64::fixup_aarch64_pcrel_adrp_imm21:
+   return COFF::IMAGE_REL_ARM64_PAGEBASE_REL21;
+
+  case AArch64::fixup_aarch64_pcrel_branch26:
+  case AArch64::fixup_aarch64_pcrel_call26:
+   return COFF::IMAGE_REL_ARM64_BRANCH26;
+  }
+}
 
 bool AArch64WinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
   return true;
 }
 
 namespace llvm {
 
 MCObjectWriter *createAArch64WinCOFFObjectWriter(raw_pwrite_stream &OS) {
   MCWinCOFFObjectTargetWriter *MOTW = new AArch64WinCOFFObjectWriter();
   return createWinCOFFObjectWriter(MOTW, OS);
 }
 
 } // end namespace llvm

test/MC/AArch64/coff-relocations.s

+; RUN: llvm-mc -triple aarch64-windows -filetype obj -o - %s \
+; RUN:   | llvm-readobj -r - | FileCheck %s -check-prefix CHECK-RELOC
+
+branch26:
+  b target
+
+pagebase_rel21:
+  adrp x0, foo
+
+
+; CHECK-RELOC: Relocations [
+; CHECK-RELOC:   Section (1) .text {
+; CHECK-RELOC:     0x0 IMAGE_REL_ARM64_BRANCH26 target
+; CHECK-RELOC:     0x4 IMAGE_REL_ARM64_PAGEBASE_REL21 foo
+; CHECK-RELOC:   }
+; CHECK-RELOC: ]