[lld][Hexagon] Add GOTREL relocations

[sidneym]

Summary

Add support for GOTREL relocations and test case.

[MaskRay]

Where can we find a psABI describing these relocation types?

[MaskRay]

lld/test/ELF/hexagon-gotrel.s

2

%t.o

4

I'd use %t2.so because it makes it stand out that %t2.so is created from %t2.so

5

-soname %t4.so is not needed because %t4.so is the final output. The rule to use -soname:

When linking an executable with %t.so, the path %t.so will be recorded in the DT_NEEDED entry if %t.so doesn't have DT_SONAME. .dynstr will have varying lengths on different systems. Add -soname so that the string in .dynstr is of fixed length to make tests more robust.

If you name the object %t.o, %t will be a good output name.

[sidneym]

Update filenames in testcase.

[sidneym]

In D66260#1630853, @MaskRay wrote:

Where can we find a psABI describing these relocation types?

You can find it here: https://developer.qualcomm.com/download/hexagon/hexagon-application-binary-interface-specification.zip?referrer=node/6116
but there is a click-through license and registration.

[ruiu]

LGTM

[MaskRay]

https://developer.qualcomm.com/download/hexagon/hexagon-application-binary-interface-specification.zip?referrer=node/6116

Still having trouble to access this.

Is openid.qualcomm.com down right now?

It's not just you! openid.qualcomm.com is down.

I think it was the case when I tried to access it one week ago..

[ruiu]

In D66260#1631500, @sidneym wrote:

In D66260#1630853, @MaskRay wrote:

Where can we find a psABI describing these relocation types?

You can find it here: https://developer.qualcomm.com/download/hexagon/hexagon-application-binary-interface-specification.zip?referrer=node/6116
but there is a click-through license and registration.

Sid,

Unfortunately it is hard to consider some document being publicly available if the document is behind a click-through license agreement page. Employed developers would have to consult their legal department to click the "agree" button, and some people may not be able to agree for various reasons. Do you think you can put the document in a non-guarded part of the website?

lld/ELF/Arch/Hexagon.cpp

RelExpr Hexagon::getRelExpr(RelType type, const Symbol &s,
   case R_HEX_6_PCREL_X:
   case R_HEX_32_PCREL:
     return R_PC;
   case R_HEX_B22_PCREL:
   case R_HEX_PLT_B22_PCREL:
   case R_HEX_B22_PCREL_X:
   case R_HEX_B32_PCREL_X:
     return R_PLT_PC;
+  case R_HEX_GOTREL_LO16:
+  case R_HEX_GOTREL_HI16:
+  case R_HEX_GOTREL_11_X:
+  case R_HEX_GOTREL_16_X:
+  case R_HEX_GOTREL_32_6_X:
+    return R_GOTPLTREL;
   case R_HEX_GOT_11_X:
   case R_HEX_GOT_16_X:
   case R_HEX_GOT_32_6_X:
     return R_HEXAGON_GOT;
   default:
     return R_ABS;
   }
 }
void Hexagon::relocateOne(uint8_t *loc, RelType type, uint64_t val) const {
   case R_HEX_9_X:
     or32le(loc, applyMask(0x00003fe0, val & 0x3f));
     break;
   case R_HEX_10_X:
     or32le(loc, applyMask(0x00203fe0, val & 0x3f));
     break;
   case R_HEX_11_X:
   case R_HEX_GOT_11_X:
+  case R_HEX_GOTREL_11_X:
     or32le(loc, applyMask(findMaskR11(read32le(loc)), val & 0x3f));
     break;
   case R_HEX_12_X:
     or32le(loc, applyMask(0x000007e0, val));
     break;
   case R_HEX_16_X: // These relocs only have 6 effective bits.
   case R_HEX_GOT_16_X:
+  case R_HEX_GOTREL_16_X:
     or32le(loc, applyMask(findMaskR16(read32le(loc)), val & 0x3f));
     break;
   case R_HEX_32:
   case R_HEX_32_PCREL:
     or32le(loc, val);
     break;
   case R_HEX_32_6_X:
   case R_HEX_GOT_32_6_X:
+  case R_HEX_GOTREL_32_6_X:
     or32le(loc, applyMask(0x0fff3fff, val >> 6));
     break;
   case R_HEX_B9_PCREL:
     or32le(loc, applyMask(0x003000fe, val >> 2));
     break;
   case R_HEX_B9_PCREL_X:
     or32le(loc, applyMask(0x003000fe, val & 0x3f));
     break;
case R_HEX_PLT_B22_PCREL:
     break;
   case R_HEX_B22_PCREL_X:
     or32le(loc, applyMask(0x1ff3ffe, val & 0x3f));
     break;
   case R_HEX_B32_PCREL_X:
     or32le(loc, applyMask(0x0fff3fff, val >> 6));
     break;
   case R_HEX_HI16:
+  case R_HEX_GOTREL_HI16:
     or32le(loc, applyMask(0x00c03fff, val >> 16));
     break;
   case R_HEX_LO16:
+  case R_HEX_GOTREL_LO16:
     or32le(loc, applyMask(0x00c03fff, val));
     break;
   default:
     error(getErrorLocation(loc) + "unrecognized relocation " + toString(type));
     break;
   }
 }
 

lld/test/ELF/hexagon-gotrel.s

+# REQUIRES: hexagon
+# RUN: llvm-mc -filetype=obj -triple=hexagon-unknown-elf %s -o %t
+# RUN: llvm-mc -filetype=obj -triple=hexagon-unknown-elf %S/Inputs/hexagon-shared.s -o %t2.o
+# RUN: ld.lld -shared %t2.o -soname %t3.so -o %t3.so
+# RUN: ld.lld -shared %t %t3.so -soname %t4.so -o %t4.so
+# RUN: llvm-objdump --print-imm-hex -d -j .text %t4.so | FileCheck --check-prefix=TEXT %s
+
+.global foo
+foo:
+
+.Lpc:
+  
+# R_HEX_GOTREL_LO16
+  r0.l = #LO(.Lpc@GOTREL)
+# R_HEX_GOTREL_HI16
+  r0.h = #HI(.Lpc@GOTREL)
+# R_HEX_GOTREL_11_X
+  r0 = memw(r1+##.Lpc@GOTREL)
+# R_HEX_GOTREL_32_6_X and R_HEX_GOTREL_16_X
+  r0 = ##(.Lpc@GOTREL)
+
+# TEXT: r0.l = #0x0 } 
+# TEXT: r0.h = #0xfffe } 
+# TEXT: immext(#0xfffe0000)
+# TEXT: r0 = memw(r1+##-0x20000) } 
+# TEXT: immext(#0xfffe0000)
+# TEXT: r0 = ##-0x20000 }