[RISCV] Add Custom Parser for Atomic Memory Operands
Summary:
GCC Accepts both (reg) and 0(reg) for atomic instruction memory
operands. These instructions do not allow for an offset in their
encoding, so in the latter case, the 0 is silently dropped.
Due to how we have structured the RISCVAsmParser, the easiest way to add
support for parsing this offset is to add a custom AsmOperand and
parser. This parser drops all the parens, and just keeps the register.
This commit also adds a custom printer for these operands, which matches
the GCC canonical printer, printing both `(a0)` and `0(a0)` as `(a0)`.
Reviewers: asb, lewis-revill
Reviewed By: asb
Subscribers: s.egerton, hiraditya, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, kito-cheng, shiva0217, jrtc27, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, rkruppe, jfb, PkmX, jocewei, psnobl, benna, Jim, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65205
llvm-svn: 367553
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVInstPrinter.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVInstPrinter.cpp
index fe37b70..d745220 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVInstPrinter.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVInstPrinter.cpp
@@ -112,3 +112,15 @@
static_cast<RISCVFPRndMode::RoundingMode>(MI->getOperand(OpNo).getImm());
O << RISCVFPRndMode::roundingModeToString(FRMArg);
}
+
+void RISCVInstPrinter::printAtomicMemOp(const MCInst *MI, unsigned OpNo,
+ const MCSubtargetInfo &STI,
+ raw_ostream &O) {
+ const MCOperand &MO = MI->getOperand(OpNo);
+
+ assert(MO.isReg() && "printAtomicMemOp can only print register operands");
+ O << "(";
+ printRegName(O, MO.getReg());
+ O << ")";
+ return;
+}