[ELF] Name ctx->objectFiles[0] in the EF_RISCV_FLOAT_ABI mismatch error

lld/ELF/Arch/RISCV.cpp

uint32_t RISCV::calcEFlags() const {
   uint32_t target = getEFlags(ctx->objectFiles.front());
 
   for (InputFile *f : ctx->objectFiles) {
     uint32_t eflags = getEFlags(f);
     if (eflags & EF_RISCV_RVC)
       target |= EF_RISCV_RVC;
 
     if ((eflags & EF_RISCV_FLOAT_ABI) != (target & EF_RISCV_FLOAT_ABI))
-      error(toString(f) +
-            ": cannot link object files with different floating-point ABI");
+      error(
+          toString(f) +
+          ": cannot link object files with different floating-point ABI from " +
+          toString(ctx->objectFiles[0]));
 
     if ((eflags & EF_RISCV_RVE) != (target & EF_RISCV_RVE))
       error(toString(f) +
             ": cannot link object files with different EF_RISCV_RVE");
   }
 
   return target;
 }

lld/test/ELF/riscv-flags.s

+# REQUIRES: riscv
+
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -target-abi=lp64d -mattr=+d %s -o %td.o
+# RUN: llvm-mc -filetype=obj -triple=riscv64 -target-abi=lp64f -mattr=+f %s -o %tf.o
+# RUN: not ld.lld %td.o %tf.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=ERR -DF1=%td.o -DF2=%tf.o
+
+# ERR: error: [[F2]]: cannot link object files with different floating-point ABI from [[F1]]