[llvm-branch-commits] [ARM, MC] Support FDPIC relocations (PR #82187)

[Fangrui Song via llvm-branch-commits]

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@@ -11358,6 +11361,37 @@ bool ARMAsmParser::parseDirectiveARM(SMLoc L) {
   return false;
 }
 
+MCSymbolRefExpr::VariantKind
+ARMAsmParser::getVariantKindForName(StringRef Name) const {
+  return StringSwitch<MCSymbolRefExpr::VariantKind>(Name.lower())
+      .Case("funcdesc", MCSymbolRefExpr::VK_FUNCDESC)
+      .Case("got", MCSymbolRefExpr::VK_GOT)
+      .Case("got_prel", MCSymbolRefExpr::VK_ARM_GOT_PREL)
+      .Case("gotfuncdesc", MCSymbolRefExpr::VK_GOTFUNCDESC)
+      .Case("gotoff", MCSymbolRefExpr::VK_GOTOFF)
+      .Case("gotofffuncdesc", MCSymbolRefExpr::VK_GOTOFFFUNCDESC)
+      .Case("gottpoff", MCSymbolRefExpr::VK_GOTTPOFF)
+      .Case("gottpoff_fdpic", MCSymbolRefExpr::VK_GOTTPOFF_FDPIC)
+      .Case("imgrel", MCSymbolRefExpr::VK_COFF_IMGREL32)
+      .Case("none", MCSymbolRefExpr::VK_ARM_NONE)
+      .Case("plt", MCSymbolRefExpr::VK_PLT)
+      .Case("prel31", MCSymbolRefExpr::VK_ARM_PREL31)
+      .Case("sbrel", MCSymbolRefExpr::VK_ARM_SBREL)
+      .Case("secrel32", MCSymbolRefExpr::VK_SECREL)
+      .Case("target1", MCSymbolRefExpr::VK_ARM_TARGET1)
+      .Case("target2", MCSymbolRefExpr::VK_ARM_TARGET2)
+      .Case("tlscall", MCSymbolRefExpr::VK_TLSCALL)
+      .Case("tlsdesc", MCSymbolRefExpr::VK_TLSDESC)
+      .Case("tlsgd", MCSymbolRefExpr::VK_TLSGD)
+      .Case("tlsgd_fdpic", MCSymbolRefExpr::VK_TLSGD_FDPIC)
+      .Case("tlsld", MCSymbolRefExpr::VK_TLSLD)
+      .Case("tlsldm", MCSymbolRefExpr::VK_TLSLDM)
+      .Case("tlsldm_fdpic", MCSymbolRefExpr::VK_TLSLDM_FDPIC)
+      .Case("tlsldo", MCSymbolRefExpr::VK_ARM_TLSLDO)
+      .Case("tpoff", MCSymbolRefExpr::VK_TPOFF)
+      .Default(MCSymbolRefExpr::VK_Invalid);
----------------
MaskRay wrote:

Yes, the binutils contains `tlsdescseq`, but there is no `(tlsdescseq)` occurrence. GCC doesn't emit `(tlsdescseq)`, either.
I suspect that the entry in binutils is not used.

There is a directive named `.tlsdescseq`  (https://www.fsfla.org/~lxoliva/writeups/TLS/RFC-TLSDESC-ARM.txt), which is for TLS optimization. But GCC doesn't emit this directive.

Clang doesn't support `-mtls-dialect=gnu2` for ARM.

https://github.com/llvm/llvm-project/pull/82187