[lld] [NFC][ELF] Remove pointless NEEDS_TLSGD_TO_IE (PR #171046)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lld

@llvm/pr-subscribers-lld-elf

Author: Jessica Clarke (jrtc27)

<details>
<summary>Changes</summary>

NEEDS_TLSGD_TO_IE is only ever set when the symbol is preeptible, in
which case addTpOffsetGotEntry will just add the symbol to the GOT and
emit a symbolic tlsGotRel anyway, so there is no need to give it its own
special case.

As well as simplifying the code upstream, this is useful downstream for
Morello, which doesn't really have a proper GD/IE-to-LE relaxation, and
so for GD-to-IE can benefit from being able to use the optimisations
addTpOffsetGotEntry has for non-preemptible symbols, rather than having
to reimplement them here.


---
Full diff: https://github.com/llvm/llvm-project/pull/171046.diff


2 Files Affected:

- (modified) lld/ELF/Relocations.cpp (+2-7) 
- (modified) lld/ELF/Symbols.h (+2-2) 


``````````diff
diff --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
index ef19a2af0c4d2..59aa43036ce01 100644
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -1295,7 +1295,7 @@ unsigned RelocScan::handleTlsRelocation(RelExpr expr, RelType type,
     // label, so TLSDESC=>IE will be categorized as R_RELAX_TLS_GD_TO_LE. We fix
     // the categorization in RISCV::relocateAllosec->
     if (sym.isPreemptible) {
-      sym.setFlags(NEEDS_TLSGD_TO_IE);
+      sym.setFlags(NEEDS_TLSIE);
       sec->addReloc({ctx.target->adjustTlsExpr(type, R_RELAX_TLS_GD_TO_IE),
                      type, offset, addend, &sym});
     } else {
@@ -1635,18 +1635,13 @@ void elf::postScanRelocations(Ctx &ctx) {
       else
         got->addConstant({R_ABS, ctx.target->tlsOffsetRel, offsetOff, 0, &sym});
     }
-    if (flags & NEEDS_TLSGD_TO_IE) {
-      got->addEntry(sym);
-      ctx.mainPart->relaDyn->addSymbolReloc(ctx.target->tlsGotRel, *got,
-                                            sym.getGotOffset(ctx), sym);
-    }
     if (flags & NEEDS_GOT_DTPREL) {
       got->addEntry(sym);
       got->addConstant(
           {R_ABS, ctx.target->tlsOffsetRel, sym.getGotOffset(ctx), 0, &sym});
     }
 
-    if ((flags & NEEDS_TLSIE) && !(flags & NEEDS_TLSGD_TO_IE))
+    if (flags & NEEDS_TLSIE)
       addTpOffsetGotEntry(ctx, sym);
   };
 
diff --git a/lld/ELF/Symbols.h b/lld/ELF/Symbols.h
index a7d61f48ed3d5..034c8734addb8 100644
--- a/lld/ELF/Symbols.h
+++ b/lld/ELF/Symbols.h
@@ -48,7 +48,7 @@ enum {
   NEEDS_COPY = 1 << 3,
   NEEDS_TLSDESC = 1 << 4,
   NEEDS_TLSGD = 1 << 5,
-  NEEDS_TLSGD_TO_IE = 1 << 6,
+  // 1 << 6 unused
   NEEDS_GOT_DTPREL = 1 << 7,
   NEEDS_TLSIE = 1 << 8,
   NEEDS_GOT_AUTH = 1 << 9,
@@ -352,7 +352,7 @@ class Symbol {
   bool needsDynReloc() const {
     return flags.load(std::memory_order_relaxed) &
            (NEEDS_COPY | NEEDS_GOT | NEEDS_PLT | NEEDS_TLSDESC | NEEDS_TLSGD |
-            NEEDS_TLSGD_TO_IE | NEEDS_GOT_DTPREL | NEEDS_TLSIE);
+            NEEDS_GOT_DTPREL | NEEDS_TLSIE);
   }
   void allocateAux(Ctx &ctx) {
     assert(auxIdx == 0);

``````````

</details>


https://github.com/llvm/llvm-project/pull/171046