Factor out common code from applySecRel functions.

[ruiu]

Summary

Factor out common code from applySecRel functions.

[mstorsjo]

LGTM, thanks!

lld/trunk/COFF/Chunks.cpp

 }
 
 static void add16(uint8_t *P, int16_t V) { write16le(P, read16le(P) + V); }
 static void add32(uint8_t *P, int32_t V) { write32le(P, read32le(P) + V); }
 static void add64(uint8_t *P, int64_t V) { write64le(P, read64le(P) + V); }
 static void or16(uint8_t *P, uint16_t V) { write16le(P, read16le(P) | V); }
 static void or32(uint8_t *P, uint32_t V) { write32le(P, read32le(P) | V); }
 
-static void applySecRel(const SectionChunk *Sec, uint8_t *Off,
-                        OutputSection *OS, uint64_t S) {
-  if (!OS) {
-    if (Sec->isCodeView())
-      return;
-    fatal("SECREL relocation cannot be applied to absolute symbols");
-  }
+// Verify that given sections are appropriate targets for SECREL
+// relocations. This check is relaxed because unfortunately debug
+// sections have section-relative relocations against absolute symbols.
+static bool checkSecRel(const SectionChunk *Sec, OutputSection *OS) {
+  if (OS)
+    return true;
+    return false;
+
+static void applySecRel(const SectionChunk *Sec, uint8_t *Off,
+                        OutputSection *OS, uint64_t S) {
+  if (!checkSecRel(Sec, OS))
+    return;
   uint64_t SecRel = S - OS->getRVA();
   if (SecRel > UINT32_MAX) {
     error("overflow in SECREL relocation in section: " + Sec->getSectionName());
     return;
   }
   add32(Off, SecRel);
 }
 
static void applyArm64Ldr(uint8_t *Off, uint64_t Imm) {
   // 0x00800000 indicates 128 bit
   if ((Orig & 0x4800000) == 0x4800000)
     Size += 4;
   if ((Imm & ((1 << Size) - 1)) != 0)
     fatal("misaligned ldr/str offset");
   applyArm64Imm(Off, Imm >> Size, Size);
 }
 
-static void applySecRelAdd(const SectionChunk *Sec, uint8_t *Off,
-                           OutputSection *OS, uint64_t S, int Shift) {
-  if (!OS) {
-    if (Sec->isCodeView())
-      return;
-    fatal("SECREL relocation cannot be applied to absolute symbols");
-  }
-  uint64_t SecRel = S - OS->getRVA();
-  SecRel >>= Shift;
-  if (Shift > 0 && SecRel > 0xfff) {
+static void applySecRelLow12A(const SectionChunk *Sec, uint8_t *Off,
+                              OutputSection *OS, uint64_t S) {
+  if (checkSecRel(Sec, OS))
+    applyArm64Imm(Off, (S - OS->getRVA()) & 0xfff, 0);
+
+static void applySecRelHigh12A(const SectionChunk *Sec, uint8_t *Off,
+                               OutputSection *OS, uint64_t S) {
+  if (!checkSecRel(Sec, OS))
+    return;
+  uint64_t SecRel = (S - OS->getRVA()) >> 12;
+  if (0xfff < SecRel) {
     error("overflow in SECREL_HIGH12A relocation in section: " +
           Sec->getSectionName());
     return;
   }
   applyArm64Imm(Off, SecRel & 0xfff, 0);
 }
 
 static void applySecRelLdr(const SectionChunk *Sec, uint8_t *Off,
                            OutputSection *OS, uint64_t S) {
-  if (!OS) {
-    if (Sec->isCodeView())
-      return;
-    fatal("SECREL relocation cannot be applied to absolute symbols");
-  }
-  uint64_t SecRel = S - OS->getRVA();
-  applyArm64Ldr(Off, SecRel & 0xfff);
+  if (checkSecRel(Sec, OS))
+    applyArm64Ldr(Off, (S - OS->getRVA()) & 0xfff);
 }
 
 void SectionChunk::applyRelARM64(uint8_t *Off, uint16_t Type, OutputSection *OS,
                                  uint64_t S, uint64_t P) const {
   switch (Type) {
   case IMAGE_REL_ARM64_PAGEBASE_REL21: applyArm64Addr(Off, S, P); break;
   case IMAGE_REL_ARM64_PAGEOFFSET_12A: applyArm64Imm(Off, S & 0xfff, 0); break;
   case IMAGE_REL_ARM64_PAGEOFFSET_12L: applyArm64Ldr(Off, S & 0xfff); break;
   case IMAGE_REL_ARM64_BRANCH26:       or32(Off, ((S - P) & 0x0FFFFFFC) >> 2); break;
   case IMAGE_REL_ARM64_ADDR32:         add32(Off, S + Config->ImageBase); break;
   case IMAGE_REL_ARM64_ADDR32NB:       add32(Off, S); break;
   case IMAGE_REL_ARM64_ADDR64:         add64(Off, S + Config->ImageBase); break;
   case IMAGE_REL_ARM64_SECREL:         applySecRel(this, Off, OS, S); break;
-  case IMAGE_REL_ARM64_SECREL_LOW12A:  applySecRelAdd(this, Off, OS, S, 0); break;
-  case IMAGE_REL_ARM64_SECREL_HIGH12A: applySecRelAdd(this, Off, OS, S, 12); break;
+  case IMAGE_REL_ARM64_SECREL_LOW12A:  applySecRelLow12A(this, Off, OS, S); break;
+  case IMAGE_REL_ARM64_SECREL_HIGH12A: applySecRelHigh12A(this, Off, OS, S); break;
   case IMAGE_REL_ARM64_SECREL_LOW12L:  applySecRelLdr(this, Off, OS, S); break;
   default:
     fatal("unsupported relocation type 0x" + Twine::utohexstr(Type));
   }
 }
 
 void SectionChunk::writeTo(uint8_t *Buf) const {
   if (!hasData())