[mips] Added support for using the command line options -Wa,-msoft-float and -Wa,-mhard-float.

[dsanders]

LGTM

It's not for this patch but I think we need a general solution to the -Wa,... options. It seems wrong to implement each assembler option twice (both with and without the '-Wa,').

lib/Driver/Tools.cpp

for (const StringRef Value : A->getValues()) {
                  Value.startswith("-mhwdiv") || Value.startswith("-march")) {
         // Do nothing, we'll validate it later.
       } else if (Value == "--trap") {
         CmdArgs.push_back("-target-feature");
         CmdArgs.push_back("+use-tcc-in-div");
       } else if (Value == "--break") {
         CmdArgs.push_back("-target-feature");
         CmdArgs.push_back("-use-tcc-in-div");
+      } else if (Value.startswith("-msoft-float")) {
+        CmdArgs.push_back("-target-feature");
+        CmdArgs.push_back("+soft-float");
+      } else if (Value.startswith("-mhard-float")) {
+        CmdArgs.push_back("-target-feature");
+        CmdArgs.push_back("-soft-float");
       } else {
         D.Diag(diag::err_drv_unsupported_option_argument)
             << A->getOption().getName() << Value;
       }
     }
   }
   if (CompressDebugSections) {
     if (llvm::zlib::isAvailable())

test/Driver/mips-ias-Wa.s

 // RUN:   FileCheck -check-prefix=TRAP-BOTH-TRAP-FIRST %s
 // TRAP-BOTH-TRAP-FIRST: -cc1as
 // TRAP-BOTH-TRAP-FIRST: "-target-feature" "+use-tcc-in-div" "-target-feature" "-use-tcc-in-div"
 
 // RUN: %clang -target mips-linux-gnu -### -fintegrated-as -c %s -Wa,--break,--trap 2>&1 | \
 // RUN:   FileCheck -check-prefix=TRAP-BOTH-BREAK-FIRST %s
 // TRAP-BOTH-BREAK-FIRST: -cc1as
 // TRAP-BOTH-BREAK-FIRST: "-target-feature" "-use-tcc-in-div" "-target-feature" "+use-tcc-in-div"
+
+// RUN: %clang -target mips-linux-gnu -### -fintegrated-as -c %s 2>&1 | \
+// RUN:   FileCheck -check-prefix=MSOFT-FLOAT-DEFAULT %s
+// MSOFT-FLOAT-DEFAULT: -cc1as
+// MSOFT-FLOAT-DEFAULT-NOT: "-target-feature" "-soft-float"
+
+// RUN: %clang -target mips-linux-gnu -### -fintegrated-as -c %s -Wa,-msoft-float 2>&1 | \
+// RUN:   FileCheck -check-prefix=MSOFT-FLOAT-ON %s
+// MSOFT-FLOAT-ON: -cc1as
+// MSOFT-FLOAT-ON: "-target-feature" "+soft-float"
+
+// RUN: %clang -target mips-linux-gnu -### -fintegrated-as -c %s -Wa,-mhard-float 2>&1 | \
+// RUN:   FileCheck -check-prefix=MSOFT-FLOAT-OFF %s
+// MSOFT-FLOAT-OFF: -cc1as
+// MSOFT-FLOAT-OFF: "-target-feature" "-soft-float"
+
+// RUN: %clang -target mips-linux-gnu -### -fintegrated-as -c %s -Wa,-msoft-float,-mhard-float 2>&1 | \
+// RUN:   FileCheck -check-prefix=MSOFT-FLOAT-BOTH-MSOFT-FLOAT-FIRST %s
+// MSOFT-FLOAT-BOTH-MSOFT-FLOAT-FIRST: -cc1as
+// MSOFT-FLOAT-BOTH-MSOFT-FLOAT-FIRST: "-target-feature" "+soft-float" "-target-feature" "-soft-float"
+
+// RUN: %clang -target mips-linux-gnu -### -fintegrated-as -c %s -Wa,-mhard-float,-msoft-float 2>&1 | \
+// RUN:   FileCheck -check-prefix=MSOFT-FLOAT-BOTH-MHARD-FLOAT-FIRST %s
+// MSOFT-FLOAT-BOTH-MHARD-FLOAT-FIRST: -cc1as
+// MSOFT-FLOAT-BOTH-MHARD-FLOAT-FIRST: "-target-feature" "-soft-float" "-target-feature" "+soft-float"