Index: cfe/trunk/lib/Driver/ToolChains/Clang.h
===================================================================
--- cfe/trunk/lib/Driver/ToolChains/Clang.h
+++ cfe/trunk/lib/Driver/ToolChains/Clang.h
@@ -119,6 +119,8 @@
                          llvm::opt::ArgStringList &CmdArgs) const;
   void AddX86TargetArgs(const llvm::opt::ArgList &Args,
                         llvm::opt::ArgStringList &CmdArgs) const;
+  void AddRISCVTargetArgs(const llvm::opt::ArgList &Args,
+                          llvm::opt::ArgStringList &CmdArgs) const;
   bool hasGoodDiagnostics() const override { return true; }
   bool hasIntegratedAssembler() const override { return false; }
   bool hasIntegratedCPP() const override { return false; }
Index: cfe/trunk/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- cfe/trunk/lib/Driver/ToolChains/Clang.cpp
+++ cfe/trunk/lib/Driver/ToolChains/Clang.cpp
@@ -5931,6 +5931,15 @@
   }
 }
 
+void ClangAs::AddRISCVTargetArgs(const ArgList &Args,
+                               ArgStringList &CmdArgs) const {
+  const llvm::Triple &Triple = getToolChain().getTriple();
+  StringRef ABIName = riscv::getRISCVABI(Args, Triple);
+
+  CmdArgs.push_back("-target-abi");
+  CmdArgs.push_back(ABIName.data());
+}
+
 void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
                            const InputInfo &Output, const InputInfoList &Inputs,
                            const ArgList &Args,
@@ -6100,6 +6109,11 @@
         CmdArgs.push_back("-arm-add-build-attributes");
     }
     break;
+
+  case llvm::Triple::riscv32:
+  case llvm::Triple::riscv64:
+    AddRISCVTargetArgs(Args, CmdArgs);
+    break;
   }
 
   // Consume all the warning flags. Usually this would be handled more
Index: cfe/trunk/test/Driver/riscv-abi.c
===================================================================
--- cfe/trunk/test/Driver/riscv-abi.c
+++ cfe/trunk/test/Driver/riscv-abi.c
@@ -2,6 +2,10 @@
 // RUN:   | FileCheck -check-prefix=CHECK-ILP32 %s
 // RUN: %clang -target riscv32-unknown-elf %s -### -o %t.o -mabi=ilp32 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-ILP32 %s
+// RUN: %clang -target riscv32-unknown-elf -x assembler %s -### -o %t.o 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-ILP32 %s
+// RUN: %clang -target riscv32-unknown-elf -x assembler %s -### -o %t.o \
+// RUN:   -mabi=ilp32 2>&1 | FileCheck -check-prefix=CHECK-ILP32 %s
 
 // CHECK-ILP32: "-target-abi" "ilp32"
 
@@ -26,6 +30,10 @@
 // RUN:   | FileCheck -check-prefix=CHECK-LP64 %s
 // RUN: %clang -target riscv64-unknown-elf %s -### -o %t.o -mabi=lp64 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK-LP64 %s
+// RUN: %clang -target riscv64-unknown-elf -x assembler %s -### -o %t.o 2>&1 \
+// RUN:   | FileCheck -check-prefix=CHECK-LP64  %s
+// RUN: %clang -target riscv64-unknown-elf -x assembler %s -### -o %t.o \
+// RUN:   -mabi=lp64 2>&1 | FileCheck -check-prefix=CHECK-LP64 %s
 
 // CHECK-LP64: "-target-abi" "lp64"
 
Index: cfe/trunk/tools/driver/cc1as_main.cpp
===================================================================
--- cfe/trunk/tools/driver/cc1as_main.cpp
+++ cfe/trunk/tools/driver/cc1as_main.cpp
@@ -137,6 +137,10 @@
   /// The name of the relocation model to use.
   std::string RelocationModel;
 
+  /// The ABI targeted by the backend. Specified using -target-abi. Empty
+  /// otherwise.
+  std::string TargetABI;
+
   /// @}
 
 public:
@@ -282,6 +286,7 @@
   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
   Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
   Opts.RelocationModel = Args.getLastArgValue(OPT_mrelocation_model, "pic");
+  Opts.TargetABI = Args.getLastArgValue(OPT_target_abi);
   Opts.IncrementalLinkerCompatible =
       Args.hasArg(OPT_mincremental_linker_compatible);
   Opts.SymbolDefs = Args.getAllArgValues(OPT_defsym);
@@ -426,6 +431,9 @@
   raw_pwrite_stream *Out = FDOS.get();
   std::unique_ptr<buffer_ostream> BOS;
 
+  MCTargetOptions MCOptions;
+  MCOptions.ABIName = Opts.TargetABI;
+
   // FIXME: There is a bit of code duplication with addPassesToEmitFile.
   if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
     MCInstPrinter *IP = TheTarget->createMCInstPrinter(
@@ -434,7 +442,6 @@
     std::unique_ptr<MCCodeEmitter> CE;
     if (Opts.ShowEncoding)
       CE.reset(TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
-    MCTargetOptions MCOptions;
     std::unique_ptr<MCAsmBackend> MAB(
         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
 
@@ -455,7 +462,6 @@
 
     std::unique_ptr<MCCodeEmitter> CE(
         TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
-    MCTargetOptions MCOptions;
     std::unique_ptr<MCAsmBackend> MAB(
         TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
     std::unique_ptr<MCObjectWriter> OW =
@@ -489,9 +495,8 @@
       createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
 
   // FIXME: init MCTargetOptions from sanitizer flags here.
-  MCTargetOptions Options;
   std::unique_ptr<MCTargetAsmParser> TAP(
-      TheTarget->createMCAsmParser(*STI, *Parser, *MCII, Options));
+      TheTarget->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
   if (!TAP)
     Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;