[PAC][lld][AArch64][ELF] Support signed GOT with tiny code model (#113816)

Depends on #114525

Support `R_AARCH64_AUTH_GOT_ADR_PREL_LO21` and `R_AARCH64_AUTH_GOT_LD_PREL19`
GOT-generating relocations. A corresponding `RE_AARCH64_AUTH_GOT_PC` member
of `RelExpr` is added, which is an AUTH-specific variant of `R_GOT_PC`.

Author: kovdan01

lld/ELF/Arch/AArch64.cpp

@@ -205,6 +205,9 @@ RelExpr AArch64::getRelExpr(RelType type, const Symbol &s,
   case R_AARCH64_AUTH_LD64_GOT_LO12_NC:
   case R_AARCH64_AUTH_GOT_ADD_LO12_NC:
     return RE_AARCH64_AUTH_GOT;
+  case R_AARCH64_AUTH_GOT_LD_PREL19:
+  case R_AARCH64_AUTH_GOT_ADR_PREL_LO21:
+    return RE_AARCH64_AUTH_GOT_PC;
   case R_AARCH64_LD64_GOTPAGE_LO15:
     return RE_AARCH64_GOT_PAGE;
   case R_AARCH64_ADR_GOT_PAGE:
@@ -548,6 +551,7 @@ void AArch64::relocate(uint8_t *loc, const Relocation &rel,
     write32AArch64Addr(loc, val >> 12);
     break;
   case R_AARCH64_ADR_PREL_LO21:
+  case R_AARCH64_AUTH_GOT_ADR_PREL_LO21:
     checkInt(ctx, loc, val, 21, rel);
     write32AArch64Addr(loc, val);
     break;
@@ -568,6 +572,7 @@ void AArch64::relocate(uint8_t *loc, const Relocation &rel,
   case R_AARCH64_CONDBR19:
   case R_AARCH64_LD_PREL_LO19:
   case R_AARCH64_GOT_LD_PREL19:
+  case R_AARCH64_AUTH_GOT_LD_PREL19:
     checkAlignment(ctx, loc, val, 4, rel);
     checkInt(ctx, loc, val, 21, rel);
     writeMaskedBits32le(loc, (val & 0x1FFFFC) << 3, 0x1FFFFC << 3);

lld/ELF/InputSection.cpp

@@ -817,6 +817,7 @@ uint64_t InputSectionBase::getRelocTargetVA(Ctx &ctx, const Relocation &r,
   case RE_AARCH64_GOT_PAGE:
     return r.sym->getGotVA(ctx) + a - getAArch64Page(ctx.in.got->getVA());
   case R_GOT_PC:
+  case RE_AARCH64_AUTH_GOT_PC:
   case R_RELAX_TLS_GD_TO_IE:
     return r.sym->getGotVA(ctx) + a - p;
   case R_GOTPLT_GOTREL:

lld/ELF/Relocations.cpp

@@ -197,8 +197,9 @@ static bool needsPlt(RelExpr expr) {
 }
 
 bool lld::elf::needsGot(RelExpr expr) {
-  return oneof<R_GOT, RE_AARCH64_AUTH_GOT, R_GOT_OFF, RE_MIPS_GOT_LOCAL_PAGE,
-               RE_MIPS_GOT_OFF, RE_MIPS_GOT_OFF32, RE_AARCH64_GOT_PAGE_PC,
+  return oneof<R_GOT, RE_AARCH64_AUTH_GOT, RE_AARCH64_AUTH_GOT_PC, R_GOT_OFF,
+               RE_MIPS_GOT_LOCAL_PAGE, RE_MIPS_GOT_OFF, RE_MIPS_GOT_OFF32,
+               RE_AARCH64_GOT_PAGE_PC, RE_AARCH64_AUTH_GOT_PAGE_PC,
                RE_AARCH64_AUTH_GOT_PAGE_PC, R_GOT_PC, R_GOTPLT,
                RE_AARCH64_GOT_PAGE, RE_LOONGARCH_GOT, RE_LOONGARCH_GOT_PAGE_PC>(
       expr);
@@ -974,15 +975,15 @@ bool RelocationScanner::isStaticLinkTimeConstant(RelExpr e, RelType type,
                                                  const Symbol &sym,
                                                  uint64_t relOff) const {
   // These expressions always compute a constant
-  if (oneof<R_GOTPLT, R_GOT_OFF, R_RELAX_HINT, RE_MIPS_GOT_LOCAL_PAGE,
-            RE_MIPS_GOTREL, RE_MIPS_GOT_OFF, RE_MIPS_GOT_OFF32,
-            RE_MIPS_GOT_GP_PC, RE_AARCH64_GOT_PAGE_PC,
-            RE_AARCH64_AUTH_GOT_PAGE_PC, R_GOT_PC, R_GOTONLY_PC,
-            R_GOTPLTONLY_PC, R_PLT_PC, R_PLT_GOTREL, R_PLT_GOTPLT,
-            R_GOTPLT_GOTREL, R_GOTPLT_PC, RE_PPC32_PLTREL, RE_PPC64_CALL_PLT,
-            RE_PPC64_RELAX_TOC, RE_RISCV_ADD, RE_AARCH64_GOT_PAGE,
-            RE_AARCH64_AUTH_GOT, RE_LOONGARCH_PLT_PAGE_PC, RE_LOONGARCH_GOT,
-            RE_LOONGARCH_GOT_PAGE_PC>(e))
+  if (oneof<
+          R_GOTPLT, R_GOT_OFF, R_RELAX_HINT, RE_MIPS_GOT_LOCAL_PAGE,
+          RE_MIPS_GOTREL, RE_MIPS_GOT_OFF, RE_MIPS_GOT_OFF32, RE_MIPS_GOT_GP_PC,
+          RE_AARCH64_GOT_PAGE_PC, RE_AARCH64_AUTH_GOT_PAGE_PC, R_GOT_PC,
+          R_GOTONLY_PC, R_GOTPLTONLY_PC, R_PLT_PC, R_PLT_GOTREL, R_PLT_GOTPLT,
+          R_GOTPLT_GOTREL, R_GOTPLT_PC, RE_PPC32_PLTREL, RE_PPC64_CALL_PLT,
+          RE_PPC64_RELAX_TOC, RE_RISCV_ADD, RE_AARCH64_GOT_PAGE,
+          RE_AARCH64_AUTH_GOT, RE_AARCH64_AUTH_GOT_PC, RE_LOONGARCH_PLT_PAGE_PC,
+          RE_LOONGARCH_GOT, RE_LOONGARCH_GOT_PAGE_PC>(e))
     return true;
 
   // These never do, except if the entire file is position dependent or if
@@ -1096,7 +1097,8 @@ void RelocationScanner::processAux(RelExpr expr, RelType type, uint64_t offset,
     } else if (!sym.isTls() || ctx.arg.emachine != EM_LOONGARCH) {
       // Many LoongArch TLS relocs reuse the RE_LOONGARCH_GOT type, in which
       // case the NEEDS_GOT flag shouldn't get set.
-      if (expr == RE_AARCH64_AUTH_GOT || expr == RE_AARCH64_AUTH_GOT_PAGE_PC)
+      if (expr == RE_AARCH64_AUTH_GOT || expr == RE_AARCH64_AUTH_GOT_PAGE_PC ||
+          expr == RE_AARCH64_AUTH_GOT_PC)
         sym.setFlags(NEEDS_GOT | NEEDS_GOT_AUTH);
       else
         sym.setFlags(NEEDS_GOT | NEEDS_GOT_NONAUTH);

lld/ELF/Relocations.h

@@ -95,6 +95,7 @@ enum RelExpr {
   RE_AARCH64_AUTH_GOT_PAGE_PC,
   RE_AARCH64_GOT_PAGE,
   RE_AARCH64_AUTH_GOT,
+  RE_AARCH64_AUTH_GOT_PC,
   RE_AARCH64_PAGE_PC,
   RE_AARCH64_RELAX_TLS_GD_TO_IE_PAGE_PC,
   RE_AARCH64_TLSDESC_PAGE,

lld/test/ELF/aarch64-got-relocations-pauth.s

@@ -77,6 +77,60 @@ _start:
   adrp x1, :got_auth:zed
   add  x1, x1, :got_auth_lo12:zed
 
+#--- ok-tiny.s
+# RUN: llvm-mc -filetype=obj -triple=aarch64 ok-tiny.s -o ok-tiny.o
+
+# RUN: ld.lld ok-tiny.o a.so -pie -o tiny1
+# RUN: llvm-readelf -r -S -x .got tiny1 | FileCheck %s --check-prefix=TINY1
+
+# RUN: ld.lld ok-tiny.o a.o -pie -o tiny2
+# RUN: llvm-readelf -r -S -x .got -s tiny2 | FileCheck %s --check-prefix=TINY2
+
+# TINY1:      Offset            Info             Type                    Symbol's Value   Symbol's Name + Addend
+# TINY1-NEXT: 0000000000020368  0000000100000412 R_AARCH64_AUTH_GLOB_DAT 0000000000000000 bar + 0
+# TINY1-NEXT: 0000000000020370  0000000200000412 R_AARCH64_AUTH_GLOB_DAT 0000000000000000 zed + 0
+
+## Symbol's values for bar and zed are equal since they contain no content (see Inputs/shared.s)
+# TINY2:         Offset            Info             Type                    Symbol's Value   Symbol's Name + Addend
+# TINY2-NEXT:    0000000000020308  0000000000000411 R_AARCH64_AUTH_RELATIVE 10248
+# TINY2-NEXT:    0000000000020310  0000000000000411 R_AARCH64_AUTH_RELATIVE 10248
+
+# TINY1:      Hex dump of section '.got':
+# TINY1-NEXT: 0x00020368 00000000 00000080 00000000 000000a0
+##                                              ^^
+##                                              0b10000000 bit 63 address diversity = true, bits 61..60 key = IA
+##                                                                ^^
+##                                                                0b10100000 bit 63 address diversity = true, bits 61..60 key = DA
+
+# TINY2: Symbol table '.symtab' contains {{.*}} entries:
+# TINY2:    Num:    Value          Size Type    Bind   Vis       Ndx Name
+# TINY2:         0000000000010248     0 FUNC    GLOBAL DEFAULT     6 bar
+# TINY2:         0000000000010248     0 NOTYPE  GLOBAL DEFAULT     6 zed
+
+# TINY2:         Hex dump of section '.got':
+# TINY2-NEXT:    0x00020308 00000000 00000080 00000000 000000a0
+##                                              ^^
+##                                              0b10000000 bit 63 address diversity = true, bits 61..60 key = IA
+##                                                                ^^
+##                                                                0b10100000 bit 63 address diversity = true, bits 61..60 key = DA
+
+# RUN: llvm-objdump -d tiny1 | FileCheck %s --check-prefix=TINY1-ASM
+
+# TINY1-ASM:      <_start>:
+# TINY1-ASM-NEXT: adr x0, 0x20368
+# TINY1-ASM-NEXT: ldr x1, 0x20370
+
+# RUN: llvm-objdump -d tiny2 | FileCheck %s --check-prefix=TINY2-ASM
+
+# TINY2-ASM:         <_start>:
+# TINY2-ASM-NEXT:    adr x0, 0x20308
+# TINY2-ASM-NEXT:    ldr x1, 0x20310
+
+.globl _start
+_start:
+  adr  x0, :got_auth:bar
+  ldr  x1, :got_auth:zed
+
 #--- err.s
 # RUN: llvm-mc -filetype=obj -triple=aarch64 err.s -o err.o
 # RUN: not ld.lld err.o a.so -pie 2>&1 | FileCheck %s --check-prefix=ERR --implicit-check-not=error: