[Hexagon] Add support for general dynamic relocs

[sidneym]

Summary

Add support for: R_HEX_GD_GOT_11/16_X and R_HEX_GD_GOT_32_6_X

[MaskRay]

lld/test/ELF/hexagon-tls-gd.s

13

Add llvm-readobj -r %t to test %t does not have a relocation.

GD->LD still applies, even if the code sequence does not change.

23

Doesn't Hexagon need to call __tls_get_addr?

35

Since the address is insignificant, 0x{{[0-9a-f]+}}

42

Check closing brace } as well.

[MaskRay]

[Hexagon] Add support for global dynamic relocs

GD has several names, "general dynamic", "generic dynamic" (typo), "global dynamic" (likely mistake, used by gcc/clang function attribute). "General dynamic" is the canonical one.

[sidneym]

Update testcase.

• Verify the absence of relocations in the executable.
• hexagon may call tls_get_addr but the name is not explicitly stated in the ABI. The internally maintained linker will create the symbol to call which is generally "tls_get_addr". There are instances when it would not be "tls_get_addr" such as when a user built a static executable using objects built -shared -pic. In such a case the internal linker would create a stub called __hexagon_ie_tls_get_addr and call it. LLD for hexagon would not support doing this until some design could be agreed upon.
• Don't check explicit addresses in GOT.
• Added the check for the closing brace.

[bcain]

In D72522#1819964, @sidneym wrote:

Update testcase.

• Verify the absence of relocations in the executable.
• hexagon may call tls_get_addr but the name is not explicitly stated in the ABI. The internally maintained linker will create the symbol to call which is generally "tls_get_addr". There are instances when it would not be "tls_get_addr" such as when a user built a static executable using objects built -shared -pic. In such a case the internal linker would create a stub called __hexagon_ie_tls_get_addr and call it. LLD for hexagon would not support doing this until some design could be agreed upon.
• Don't check explicit addresses in GOT.
• Added the check for the closing brace.

LGTM, @sidneym. It would be more explicit if you marked the outstanding items on the review as 'DONE'.

@MaskRay / @ruiu what do you think?

[MaskRay]

lld/test/ELF/hexagon-tls-gd.s

5

excess space

13

excess space

lld/ELF/Arch/Hexagon.cpp

Hexagon::Hexagon() {
 
   pltEntrySize = 16;
   pltHeaderSize = 32;
 
   // Hexagon Linux uses 64K pages by default.
   defaultMaxPageSize = 0x10000;
   noneRel = R_HEX_NONE;
   tlsGotRel = R_HEX_TPREL_32;
+  tlsModuleIndexRel = R_HEX_DTPMOD_32;
+  tlsOffsetRel = R_HEX_DTPREL_32;
 }
 
 uint32_t Hexagon::calcEFlags() const {
   assert(!objectFiles.empty());
 
   // The architecture revision must always be equal to or greater than
   // greatest revision in the list of inputs.
   uint32_t ret = 0;
RelExpr Hexagon::getRelExpr(RelType type, const Symbol &s,
   case R_HEX_10_X:
   case R_HEX_11_X:
   case R_HEX_12_X:
   case R_HEX_16_X:
   case R_HEX_32:
   case R_HEX_32_6_X:
   case R_HEX_HI16:
   case R_HEX_LO16:
+  case R_HEX_DTPREL_32:
     return R_ABS;
   case R_HEX_B9_PCREL:
   case R_HEX_B13_PCREL:
   case R_HEX_B15_PCREL:
   case R_HEX_6_PCREL_X:
   case R_HEX_32_PCREL:
     return R_PC;
   case R_HEX_B9_PCREL_X:
   case R_HEX_B15_PCREL_X:
   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_IE_32_6_X:
   case R_HEX_IE_16_X:
   case R_HEX_IE_HI16:
   case R_HEX_IE_LO16:
     return R_GOT;
+  case R_HEX_GD_GOT_11_X:
+  case R_HEX_GD_GOT_16_X:
+  case R_HEX_GD_GOT_32_6_X:
+    return R_TLSGD_GOTPLT;
   case R_HEX_GOTREL_11_X:
   case R_HEX_GOTREL_16_X:
   case R_HEX_GOTREL_32_6_X:
   case R_HEX_GOTREL_HI16:
   case R_HEX_GOTREL_LO16:
     return R_GOTPLTREL;
   case R_HEX_GOT_11_X:
   case R_HEX_GOT_16_X:
case R_HEX_8_X:
     break;
   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_GD_GOT_11_X:
   case R_HEX_IE_GOT_11_X:
   case R_HEX_GOT_11_X:
   case R_HEX_GOTREL_11_X:
   case R_HEX_TPREL_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_IE_16_X:
   case R_HEX_IE_GOT_16_X:
+  case R_HEX_GD_GOT_16_X:
   case R_HEX_GOT_16_X:
   case R_HEX_GOTREL_16_X:
   case R_HEX_TPREL_16_X:
     or32le(loc, applyMask(findMaskR16(read32le(loc)), val & 0x3f));
     break;
   case R_HEX_TPREL_16:
     or32le(loc, applyMask(findMaskR16(read32le(loc)), val & 0xffff));
     break;
   case R_HEX_32:
   case R_HEX_32_PCREL:
+  case R_HEX_DTPREL_32:
     or32le(loc, val);
     break;
   case R_HEX_32_6_X:
+  case R_HEX_GD_GOT_32_6_X:
   case R_HEX_GOT_32_6_X:
   case R_HEX_GOTREL_32_6_X:
   case R_HEX_IE_GOT_32_6_X:
   case R_HEX_IE_32_6_X:
   case R_HEX_TPREL_32_6_X:
     or32le(loc, applyMask(0x0fff3fff, val >> 6));
     break;
   case R_HEX_B9_PCREL:

lld/test/ELF/hexagon-tls-gd.s

+# REQUIRES: hexagon
+# RUN: llvm-mc -filetype=obj -triple=hexagon-unknown-elf %s -o %t.o
+# RUN: llvm-readobj -r %t.o | FileCheck -check-prefix=RELOC %s
+# RUN: ld.lld %t.o -o %t
+# RUN: ld.lld -shared %t.o -o %t.so
+# RUN: llvm-objdump -d --no-show-raw-insn --print-imm-hex %t | FileCheck %s
+# RUN: llvm-objdump -d --no-show-raw-insn --print-imm-hex %t.so | FileCheck %s
+# RUN: llvm-readobj -x .got %t | FileCheck -check-prefix=GOT %s
+# RUN: llvm-readobj -x .got %t.so | FileCheck -check-prefix=GOT-SHARED %s
+# RUN: llvm-readobj -x .tdata %t | FileCheck -check-prefix=TDATA %s
+# RUN: llvm-readobj -x .tdata %t.so | FileCheck -check-prefix=TDATA %s
+# RUN: llvm-readobj -r %t | FileCheck -check-prefix=RELA %s
+# RUN: llvm-readobj -r %t.so | FileCheck -check-prefix=RELA-SHARED %s
+
+.globl _start
+.type _start, @function
+
+_start:
+# RELOC:      0x0 R_HEX_GD_GOT_32_6_X a 0x0
+# RELOC-NEXT: 0x4 R_HEX_GD_GOT_16_X a 0x0
+# CHECK:      {   immext(#0xfffeffc0)
+# CHECK-NEXT:     r0 = add(r1,##-0x10008) }
+                  r0 = add(r1, ##a@GDGOT)
+
+# RELOC:      0x8 R_HEX_GD_GOT_32_6_X a 0x0
+# RELOC-NEXT: 0xC R_HEX_GD_GOT_11_X a 0x0
+# CHECK-NEXT: {   immext(#0xfffeffc0)
+# CHECK-NEXT:     r0 = memw(r1+##-0x10008) }
+                  r0 = memw(r1+##a@GDGOT)
+
+# GOT: Hex dump of section '.got':
+# GOT-NEXT: 0x{{[0-9a-f]+}} 01000000 00000000
+
+# GOT-SHARED: Hex dump of section '.got':
+# GOT-SHARED-NEXT: 0x{{[0-9a-f]+}} 00000000 00000000
+
+# TDATA: Hex dump of section '.tdata':
+# TDATA-NEXT: 01000000
+
+# RELA: Relocations [
+# RELA-NEXT: ]
+
+# RELA-SHARED:      .rela.dyn {
+# RELA-SHARED-NEXT:   0x2024C R_HEX_DTPMOD_32 a 0x0
+# RELA-SHARED-NEXT:   0x20250 R_HEX_DTPREL_32 a 0x0
+# RELA-SHARED-NEXT: }
+
+.section        .tdata,"awT",@progbits
+.globl  a
+a:
+.word 1