[ELF] relocateNonAlloc & ICF: replace random access iterators of relocations with input iterators. NFC

Also replace one `this->file` with a local variable as some function
calls are opaque to the compiler, causing unneeded reload.

Author: MaskRay

lld/ELF/ICF.cpp

@@ -239,16 +239,17 @@ bool ICF<ELFT>::constantEq(const InputSection *secA, ArrayRef<RelTy> ra,
                            const InputSection *secB, ArrayRef<RelTy> rb) {
   if (ra.size() != rb.size())
     return false;
-  for (size_t i = 0; i < ra.size(); ++i) {
-    if (ra[i].r_offset != rb[i].r_offset ||
-        ra[i].getType(config->isMips64EL) != rb[i].getType(config->isMips64EL))
+  auto rai = ra.begin(), rae = ra.end(), rbi = rb.begin();
+  for (; rai != rae; ++rai, ++rbi) {
+    if (rai->r_offset != rbi->r_offset ||
+        rai->getType(config->isMips64EL) != rbi->getType(config->isMips64EL))
       return false;
 
-    uint64_t addA = getAddend<ELFT>(ra[i]);
-    uint64_t addB = getAddend<ELFT>(rb[i]);
+    uint64_t addA = getAddend<ELFT>(*rai);
+    uint64_t addB = getAddend<ELFT>(*rbi);
 
-    Symbol &sa = secA->file->getRelocTargetSym(ra[i]);
-    Symbol &sb = secB->file->getRelocTargetSym(rb[i]);
+    Symbol &sa = secA->file->getRelocTargetSym(*rai);
+    Symbol &sb = secB->file->getRelocTargetSym(*rbi);
     if (&sa == &sb) {
       if (addA == addB)
         continue;
@@ -336,10 +337,11 @@ bool ICF<ELFT>::variableEq(const InputSection *secA, ArrayRef<RelTy> ra,
                            const InputSection *secB, ArrayRef<RelTy> rb) {
   assert(ra.size() == rb.size());
 
-  for (size_t i = 0; i < ra.size(); ++i) {
+  auto rai = ra.begin(), rae = ra.end(), rbi = rb.begin();
+  for (; rai != rae; ++rai, ++rbi) {
     // The two sections must be identical.
-    Symbol &sa = secA->file->getRelocTargetSym(ra[i]);
-    Symbol &sb = secB->file->getRelocTargetSym(rb[i]);
+    Symbol &sa = secA->file->getRelocTargetSym(*rai);
+    Symbol &sb = secB->file->getRelocTargetSym(*rbi);
     if (&sa == &sb)
       continue;
 

lld/ELF/InputSection.cpp

@@ -918,32 +918,32 @@ void InputSection::relocateNonAlloc(uint8_t *buf, ArrayRef<RelTy> rels) {
       break;
     }
 
-  for (size_t i = 0, relsSize = rels.size(); i != relsSize; ++i) {
-    const RelTy &rel = rels[i];
+  const InputFile *f = this->file;
+  for (auto it = rels.begin(), end = rels.end(); it != end; ++it) {
+    const RelTy &rel = *it;
     const RelType type = rel.getType(config->isMips64EL);
     const uint64_t offset = rel.r_offset;
     uint8_t *bufLoc = buf + offset;
     int64_t addend = getAddend<ELFT>(rel);
     if (!RelTy::IsRela)
       addend += target.getImplicitAddend(bufLoc, type);
 
-    Symbol &sym = this->file->getRelocTargetSym(rel);
+    Symbol &sym = f->getRelocTargetSym(rel);
     RelExpr expr = target.getRelExpr(type, sym, bufLoc);
     if (expr == R_NONE)
       continue;
     auto *ds = dyn_cast<Defined>(&sym);
 
     if (emachine == EM_RISCV && type == R_RISCV_SET_ULEB128) {
-      if (++i < relsSize &&
-          rels[i].getType(/*isMips64EL=*/false) == R_RISCV_SUB_ULEB128 &&
-          rels[i].r_offset == offset) {
+      if (++it != end &&
+          it->getType(/*isMips64EL=*/false) == R_RISCV_SUB_ULEB128 &&
+          it->r_offset == offset) {
         uint64_t val;
         if (!ds && tombstone) {
           val = *tombstone;
         } else {
           val = sym.getVA(addend) -
-                (this->file->getRelocTargetSym(rels[i]).getVA(0) +
-                 getAddend<ELFT>(rels[i]));
+                (f->getRelocTargetSym(*it).getVA(0) + getAddend<ELFT>(*it));
         }
         if (overwriteULEB128(bufLoc, val) >= 0x80)
           errorOrWarn(getLocation(offset) + ": ULEB128 value " + Twine(val) +