[RISCV] Support .option push and .option pop

This adds support in the RISCVAsmParser the storing of Subtarget feature bits to a stack so that they can be pushed/popped to enable/disable multiple features at once.

Differential Revision: https://reviews.llvm.org/D46424
Patch by Lewis Revill.

llvm-svn: 347774

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVTargetStreamer.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVTargetStreamer.cpp
index 33c59f839ef..8d5ef3dbd17 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVTargetStreamer.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVTargetStreamer.cpp
@@ -23,6 +23,14 @@ RISCVTargetAsmStreamer::RISCVTargetAsmStreamer(MCStreamer &S,
                                                formatted_raw_ostream &OS)
     : RISCVTargetStreamer(S), OS(OS) {}
 
+void RISCVTargetAsmStreamer::emitDirectiveOptionPush() {
+  OS << "\t.option\tpush\n";
+}
+
+void RISCVTargetAsmStreamer::emitDirectiveOptionPop() {
+  OS << "\t.option\tpop\n";
+}
+
 void RISCVTargetAsmStreamer::emitDirectiveOptionRVC() {
   OS << "\t.option\trvc\n";
 }