Read target-abi from the first bitcode file for LTO

lld/test/ELF/lto/riscv32.ll

@@ -2,9 +2,17 @@
 
 ; RUN: llvm-as %s -o %t.o
 ; RUN: ld.lld %t.o -o %t
+; RUN: llvm-readelf --syms %t | FileCheck %s
+; CHECK: Symbol table '.symtab' contains 3 entries:
+; CHECK: FUNC    GLOBAL DEFAULT     1 _start
+; CHECK-EMPTY:
+
 target datalayout = "e-m:e-p:32:32-i64:64-n32-S128"
 target triple = "riscv32-unknown-elf"
 
-define void @f() {
+define void @_start() {
   ret void
 }
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"target-abi", !"ilp32"}

lld/test/ELF/lto/riscv64-purecap-infer-abi.ll

@@ -0,0 +1,35 @@
+; REQUIRES: riscv
+
+; RUN: llvm-as %s -o %t.o
+; Note: -mattr is needed since there is no global metadata for the target features,
+; but we should be able to infer target-abi from the first input file
+; RUN: ld.lld %t.o -o %t -plugin-opt=-mattr=+xcheri -e purecap_fn
+; RUN: llvm-readelf --syms --arch-specific %t | FileCheck %s
+; RUN: llvm-objdump -d %t | FileCheck %s --check-prefix=DUMP
+; CHECK: Symbol table '.symtab' contains 3 entries:
+; CHECK: FUNC    GLOBAL DEFAULT     1 purecap_fn
+; CHECK:      Attribute {
+; CHECK:        Tag: 5
+; CHECK-NEXT:   TagName: arch
+; CHECK-NEXT:   Value: rv64i2p0_xcheri0p0
+; CHECK-NEXT: }
+; DUMP: 0000000000011120 <purecap_fn>:
+; DUMP-NEXT: 11120: 5b 80 c0 fe  	cret
+
+; RUN: llvm-as %S/riscv64.ll -o %t-nocheri.o
+; RUN: not ld.lld -o %t -plugin-opt=-mattr=+xcheri %t.o %t-nocheri.o -e purecap_fn 2>&1 | FileCheck %s --check-prefix INCOMPATIBLE
+; INCOMPATIBLE: warning: Linking two modules of different data layouts: '{{.+}}riscv64-purecap-infer-abi.ll.tmp-nocheri.o' is 'e-m:e-p:64:64-i64:64-i128:128-n64-S128' whereas 'ld-temp.o' is 'e-m:e-pf200:128:128:128:64-p:64:64-i64:64-i128:128-n64-S128-A200-P200-G200'
+; INCOMPATIBLE: warning: Linking two modules of different target triples: '{{.+}}riscv64-purecap-infer-abi.ll.tmp-nocheri.o' is 'riscv64-unknown-elf' whereas 'ld-temp.o' is 'riscv64-unknown-freebsd'
+; INCOMPATIBLE: error: linking module flags 'target-abi': IDs have conflicting values in '{{.+}}riscv64-purecap-infer-abi.ll.tmp-nocheri.o' and 'ld-temp.o'
+
+target datalayout = "e-m:e-pf200:128:128:128:64-p:64:64-i64:64-i128:128-n64-S128-A200-P200-G200"
+target triple = "riscv64-unknown-freebsd"
+
+define void @purecap_fn() addrspace(200) #0 {
+entry:
+  ret void
+}
+
+attributes #0 = { nounwind "target-features"="+cap-mode,+xcheri" }
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"target-abi", !"l64pc128"}

lld/test/ELF/lto/riscv64.ll

@@ -2,9 +2,16 @@
 
 ; RUN: llvm-as %s -o %t.o
 ; RUN: ld.lld %t.o -o %t
+; RUN: llvm-readelf --syms %t | FileCheck %s
+; CHECK: Symbol table '.symtab' contains 3 entries:
+; CHECK: FUNC    GLOBAL DEFAULT     1 _start
+; CHECK-EMPTY:
 target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n64-S128"
 target triple = "riscv64-unknown-elf"
 
-define void @f() {
+define void @_start() {
   ret void
 }
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"target-abi", !"lp64"}

llvm/lib/LTO/LTOBackend.cpp

@@ -191,15 +191,24 @@ createTargetMachine(const Config &Conf, const Target *TheTarget, Module &M) {
     RelocModel =
         M.getPICLevel() == PICLevel::NotPIC ? Reloc::Static : Reloc::PIC_;
 
+  TargetOptions TOpts = Conf.Options;
+  if (const MDString *ModuleTargetABI =
+          dyn_cast_or_null<MDString>(M.getModuleFlag("target-abi"))) {
+    if (Conf.Options.MCOptions.ABIName != ModuleTargetABI->getString()) {
+      /* report_fatal_error("target-abi metadata was ignored!"); */
+      TOpts.MCOptions.ABIName = ModuleTargetABI->getString().str();
+    }
+  }
+
   Optional<CodeModel::Model> CodeModel;
   if (Conf.CodeModel)
     CodeModel = *Conf.CodeModel;
   else
     CodeModel = M.getCodeModel();
 
   std::unique_ptr<TargetMachine> TM(TheTarget->createTargetMachine(
-      TheTriple, Conf.CPU, Features.getString(), Conf.Options, RelocModel,
-      CodeModel, Conf.CGOptLevel));
+      TheTriple, Conf.CPU, Features.getString(), TOpts, RelocModel, CodeModel,
+      Conf.CGOptLevel));
   assert(TM && "Failed to create target machine");
   return TM;
 }

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

@@ -57,14 +57,16 @@ static std::string computeDataLayout(const Triple &TT, StringRef FS,
 
   StringRef CapTypes = "";
   StringRef PurecapOptions = "";
-  if (FS.contains("+xcheri")) {
+  RISCVABI::ABI ABI = RISCVABI::getTargetABI(Options.MCOptions.getABIName());
+  bool IsPurecapABI =
+      ABI != RISCVABI::ABI_Unknown && RISCVABI::isCheriPureCapABI(ABI);
+  if (FS.contains("+xcheri") || IsPurecapABI) {
     if (TT.isArch64Bit())
       CapTypes = "-pf200:128:128:128:64";
     else
       CapTypes = "-pf200:64:64:64:32";
 
-    RISCVABI::ABI ABI = RISCVABI::getTargetABI(Options.MCOptions.getABIName());
-    if (ABI != RISCVABI::ABI_Unknown && RISCVABI::isCheriPureCapABI(ABI))
+    if (IsPurecapABI)
       PurecapOptions = "-A200-P200-G200";
   }