[AArch64] Add support for the GNU ILP32 ABI

Add the aarch64[_be]-*-gnu_ilp32 targets to support the GNU ILP32 ABI for AArch64.

The needed codegen changes were mostly already implemented in D61259, which added support for the watchOS ILP32 ABI. The main changes are:
- Wiring up the new target to enable ILP32 codegen and MC.
- ILP32 va_list support.
- ILP32 TLSDESC relocation support.

There was existing MC support for ELF ILP32 relocations from D25159 which could be enabled by passing "-target-abi ilp32" to llvm-mc. This was changed to check for "gnu_ilp32" in the target triple instead. This shouldn't cause any issues since the existing support was slightly broken: it was generating ELF64 objects instead of the ELF32 object files expected by the GNU ILP32 toolchain.

This target has been tested by running the full rustc testsuite on a big-endian ILP32 system based on the GCC ILP32 toolchain.

Reviewed By: kristof.beyls

Differential Revision: https://reviews.llvm.org/D94143

1 files changed, 14 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 32e8393..4971838 100644
--- a/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -181,11 +181,20 @@ void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
     // will be in memory. Most of these could end up >2GB away so even a signed
     // pc-relative 32-bit address is insufficient, theoretically.
     if (isPositionIndependent()) {
-      PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
-        dwarf::DW_EH_PE_sdata8;
-      LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
-      TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
-        dwarf::DW_EH_PE_sdata8;
+      // ILP32 uses sdata4 instead of sdata8
+      if (TgtM.getTargetTriple().getEnvironment() == Triple::GNUILP32) {
+        PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+                              dwarf::DW_EH_PE_sdata4;
+        LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
+        TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+                        dwarf::DW_EH_PE_sdata4;
+      } else {
+        PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+                              dwarf::DW_EH_PE_sdata8;
+        LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
+        TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
+                        dwarf::DW_EH_PE_sdata8;
+      }
     } else {
       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
       LSDAEncoding = dwarf::DW_EH_PE_absptr;