[PATCH] D14870: [ELF2] - Implemented optimizations for @tlsld and @tlsgd

[Rui Ueyama via llvm-commits]

ruiu added inline comments.

================
Comment at: ELF/InputSection.cpp:142
@@ +141,3 @@
+    if (Target->isTlsOptimized(Type, &Body)) {
+      I += Target->relocateTlsOptimize(BufLoc, BufEnd, Type, AddrLoc,
+                                       getSymVA<ELFT>(Body));
----------------
Please add a comment here.

  // By optimizing TLS relocations, it is sometimes needed to skip relocations
  // that immediately follow TLS relocations. This function knows how many slots
  // we need to skip.

================
Comment at: ELF/Target.cpp:469
@@ -409,1 +468,3 @@
 
+int8_t X86_64TargetInfo::relocateTlsOptimize(uint8_t *Loc, uint8_t *BufEnd,
+                                             uint32_t Type, uint64_t P,
----------------
Please do not use int8_t just because it returns a small integer. If no specific size is in mind, use int.

================
Comment at: ELF/Target.cpp:469
@@ -409,1 +468,3 @@
 
+int8_t X86_64TargetInfo::relocateTlsOptimize(uint8_t *Loc, uint8_t *BufEnd,
+                                             uint32_t Type, uint64_t P,
----------------
ruiu wrote:
> Please do not use int8_t just because it returns a small integer. If no specific size is in mind, use int.
Add a comment

  // This function applies a TLS relocation with an optimization as described
  // in the Ulrich's document. As a result of rewriting instructions at the relocation
  // target, relocations immediately follow the TLS relocation (which would be applied
  // to rewritten instructions) need to be skipped.
  // This function returns a number of relocations that need to be skipped.

================
Comment at: ELF/Target.cpp:472-483
@@ +471,14 @@
+                                             uint64_t SA) const {
+  int8_t SkipRel = 0;
+  if (Type == R_X86_64_GOTTPOFF)
+    relocateTlsIeToLe(Loc, BufEnd, P, SA);
+  else if (Type == R_X86_64_TLSLD)
+    SkipRel += relocateTlsLdToLe(Loc, BufEnd, P, SA);
+  else if (Type == R_X86_64_TLSGD)
+    SkipRel += relocateTlsGdToLe(Loc, BufEnd, P, SA);
+  else if (Type == R_X86_64_DTPOFF32)
+    relocateOne(Loc, BufEnd, R_X86_64_TPOFF32, P, SA);
+  else
+    error("Unknown TLS optimization");
+  return SkipRel;
+}
----------------
  switch (Type) {
  case R_X86_64_GOTTPOFF:
    relocateTlsIeToLe(...);
    return 0;
  case R_X86_64_TLSLD:
    relocateTlsLdToLe(...);
    return 1;
  case ...
  }


http://reviews.llvm.org/D14870