[ELF] Rename canRelax to toExecRelax. NFC

In the absence of TLS relaxation (rewrite of code sequences),
there is still an applicable optimization:

[gd]: General Dynamic: resolve DTPMOD to 1 and/or resolve DTPOFF statically

All the other relaxations are only performed when transiting to
executable (`!config->shared`).
Since [gd] is handled differently, we can fold `!config->shared` into canRelax
and simplify its use sites. Rename the variable to reflect to new semantics.

Reviewed By: grimar, psmith

Differential Revision: https://reviews.llvm.org/D83243

lld/ELF/Relocations.cpp

@@ -197,9 +197,9 @@ handleTlsRelocation(RelType type, Symbol &sym, InputSectionBase &c,
     return 1;
   }
 
-  bool canRelax = config->emachine != EM_ARM &&
-                  config->emachine != EM_HEXAGON &&
-                  config->emachine != EM_RISCV;
+  bool toExecRelax = !config->shared && config->emachine != EM_ARM &&
+                     config->emachine != EM_HEXAGON &&
+                     config->emachine != EM_RISCV;
 
   // If we are producing an executable and the symbol is non-preemptable, it
   // must be defined and the code sequence can be relaxed to use Local-Exec.
@@ -217,7 +217,7 @@ handleTlsRelocation(RelType type, Symbol &sym, InputSectionBase &c,
   if (oneof<R_TLSLD_GOT, R_TLSLD_GOTPLT, R_TLSLD_PC, R_TLSLD_HINT>(
           expr)) {
     // Local-Dynamic relocs can be relaxed to Local-Exec.
-    if (canRelax && !config->shared) {
+    if (toExecRelax) {
       c.relocations.push_back(
           {target->adjustRelaxExpr(type, nullptr, R_RELAX_TLS_LD_TO_LE), type,
            offset, addend, &sym});
@@ -238,7 +238,7 @@ handleTlsRelocation(RelType type, Symbol &sym, InputSectionBase &c,
   }
 
   // Local-Dynamic relocs can be relaxed to Local-Exec.
-  if (expr == R_DTPREL && canRelax && !config->shared) {
+  if (expr == R_DTPREL && toExecRelax) {
     c.relocations.push_back(
         {target->adjustRelaxExpr(type, nullptr, R_RELAX_TLS_LD_TO_LE), type,
          offset, addend, &sym});
@@ -260,7 +260,7 @@ handleTlsRelocation(RelType type, Symbol &sym, InputSectionBase &c,
 
   if (oneof<R_AARCH64_TLSDESC_PAGE, R_TLSDESC, R_TLSDESC_CALL, R_TLSDESC_PC,
             R_TLSGD_GOT, R_TLSGD_GOTPLT, R_TLSGD_PC>(expr)) {
-    if (!canRelax || config->shared) {
+    if (!toExecRelax) {
       if (in.got->addDynTlsEntry(sym)) {
         uint64_t off = in.got->getGlobalDynOffset(sym);
 
@@ -308,7 +308,7 @@ handleTlsRelocation(RelType type, Symbol &sym, InputSectionBase &c,
   // defined.
   if (oneof<R_GOT, R_GOTPLT, R_GOT_PC, R_AARCH64_GOT_PAGE_PC, R_GOT_OFF,
             R_TLSIE_HINT>(expr) &&
-      canRelax && isLocalInExecutable) {
+      toExecRelax && isLocalInExecutable) {
     c.relocations.push_back({R_RELAX_TLS_IE_TO_LE, type, offset, addend, &sym});
     return 1;
   }