[AArch64] Output the pseudo SPACE in asm and object files

Summary: It outputs nothing, but is useful for writing tests, checking asm output.

Reviewers: t.p.northover, ostannard, tellenbach

Reviewed By: tellenbach

Subscribers: tellenbach, kristof.beyls, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69185

Change-Id: I6b58310e9e5632f0976d2000ce975ee28df90ebe

2 files changed, 12 insertions, 2 deletions

diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64InstPrinter.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64InstPrinter.cpp
index 1a16468484a..00d80319a83 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64InstPrinter.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64InstPrinter.cpp
@@ -282,6 +282,12 @@ void AArch64InstPrinter::printInst(const MCInst *MI, raw_ostream &O,
     return;
   }
 
+  if (Opcode == AArch64::SPACE) {
+    O << '\t' << MAI.getCommentString() << " SPACE";
+    printAnnotation(O, Annot);
+    return;
+  }
+
   // Instruction TSB is specified as a one operand instruction, but 'csync' is
   // not encoded, so for printing it is treated as a special case here:
   if (Opcode == AArch64::TSB) {
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCCodeEmitter.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCCodeEmitter.cpp
index 8cb7a167298..8f4d9cb94d6 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCCodeEmitter.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCCodeEmitter.cpp
@@ -601,8 +601,12 @@ void AArch64MCCodeEmitter::encodeInstruction(const MCInst &MI, raw_ostream &OS,
     MCFixupKind Fixup = MCFixupKind(AArch64::fixup_aarch64_tlsdesc_call);
     Fixups.push_back(MCFixup::create(0, MI.getOperand(0).getExpr(), Fixup));
     return;
-  } else if (MI.getOpcode() == AArch64::CompilerBarrier) {
-    // This just prevents the compiler from reordering accesses, no actual code.
+  }
+
+  if (MI.getOpcode() == AArch64::CompilerBarrier ||
+      MI.getOpcode() == AArch64::SPACE) {
+    // CompilerBarrier just prevents the compiler from reordering accesses, and
+    // SPACE just increases basic block size, in both cases no actual code.
     return;
   }