[LTO] Override TargetABI from module flags if present when creating TargetMachine

llvm/include/llvm/IR/Module.h

@@ -1067,6 +1067,9 @@ class LLVM_ABI Module {
 
   /// Set the target variant version build SDK version metadata.
   void setDarwinTargetVariantSDKVersion(VersionTuple Version);
+
+  /// Returns target-abi from MDString, null if target-abi is absent.
+  StringRef getTargetABIFromMD();
 };
 
 /// Given "llvm.used" or "llvm.compiler.used" as a global name, collect the

llvm/lib/IR/Module.cpp

@@ -915,3 +915,11 @@ VersionTuple Module::getDarwinTargetVariantSDKVersion() const {
 void Module::setDarwinTargetVariantSDKVersion(VersionTuple Version) {
   addSDKVersionMD(Version, *this, "darwin.target_variant.SDK Version");
 }
+
+StringRef Module::getTargetABIFromMD() {
+  StringRef TargetABI;
+  if (auto *TargetABIMD =
+          dyn_cast_or_null<MDString>(getModuleFlag("target-abi")))
+    TargetABI = TargetABIMD->getString();
+  return TargetABI;
+}

llvm/lib/LTO/LTOBackend.cpp

@@ -221,8 +221,13 @@ createTargetMachine(const Config &Conf, const Target *TheTarget, Module &M) {
   else
     CodeModel = M.getCodeModel();
 
+  TargetOptions TargetOpts = Conf.Options;
+  if (TargetOpts.MCOptions.ABIName.empty()) {
+    TargetOpts.MCOptions.ABIName = M.getTargetABIFromMD();
+  }
+
   std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine(
-      TheTriple.str(), Conf.CPU, Features.getString(), Conf.Options, RelocModel,
+      TheTriple.str(), Conf.CPU, Features.getString(), TargetOpts, RelocModel,
       CodeModel, Conf.CGOptLevel));
 
   assert(TM && "Failed to create target machine");

llvm/test/LTO/RISCV/lit.local.cfg

@@ -0,0 +1,2 @@
+if "RISCV" not in config.root.targets:
+    config.unsupported = True

llvm/test/LTO/RISCV/riscv-ilp32e.ll

@@ -0,0 +1,21 @@
+; Check that we don't crash on DataLayout incompatibility issue.
+; RUN: llvm-as %s -o %t.o
+; RUN: llvm-lto2 run -r %t.o,_start %t.o -o %t.elf
+; RUN: llvm-readobj -h %t.elf.0 | FileCheck %s --check-prefixes=CHECK
+; CHECK:  Machine: EM_RISCV (0xF3)
+; CHECK:  EF_RISCV_RVE (0x8)
+
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32-S32"
+target triple = "riscv32-unknown-unknown-elf"
+
+define dso_local i32 @_start() #0 {
+entry:
+  ret i32 0
+}
+
+attributes #0 = { "target-cpu"="generic-rv32" "target-features"="+32bit,+e" }
+
+!llvm.module.flags = !{!0}
+
+!0 = !{i32 1, !"target-abi", !"ilp32e"}