[mips] Move expansion of .cpsetup to target streamer.

[matheusalmeida]

Summary

There are two functional changes:

1. The directive is not expanded for the ASM->ASM code path.
2. If PIC is not set, there's no expansion for the ASM->OBJ code path (same behaviour as GAS).

[matheusalmeida]

The description is not entirely right... There are two functional changes:

1. The directive is not expanded for the ASM->ASM code path
2. If PIC is not set, there's no expansion for the ASM->OBJ code path.

[dsanders]

test/MC/Mips/cpsetup.s

35–39

Please re-add the check for the relocations

55–59

here too

67–74

I believe .cpsetup shouldn't emit any instructions in this case. If so, it would be more robust to add a label immediately after the directive and use CHECK-NEXT.

[matheusalmeida]

Added reloc information to the test now that it's possible to print it
with llvm-objdump.

The test has a FIXME because direct object emission for N32 does not work properly (yet).
At the moment we emit an ELF64 instead of an ELF32 and encode more than one operation in
a relocation record which is only valid for n64.

[dsanders]

LGTM

lib/Target/Mips/MipsTargetStreamer.h

144–145

I believe that the 'virtual' keyword should be dropped when 'override' is used

[matheusalmeida]

lib/Target/Mips/MipsTargetStreamer.h

144–145

I saw a thread this morning discussing it and I forgot to update this patch. Thanks.

[matheusalmeida]

Remove virtual keyword.

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

bool MipsAsmParser::parseDirectiveCPSetup() {
 
   if (!eatComma("expected comma parsing directive"))
     return true;
 
   StringRef Name;
   if (Parser.parseIdentifier(Name))
     reportParseError("expected identifier");
   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
-  unsigned GPReg = getGPR(matchCPURegisterName("gp"));
 
-  // FIXME: The code below this point should be in the TargetStreamers.
-  // Only N32 and N64 emit anything for .cpsetup
-  // FIXME: We should only emit something for PIC mode too.
-  if (!isN32() && !isN64())
-    return false;
-
-  MCStreamer &TS = getStreamer();
-  MCInst Inst;
-  // Either store the old $gp in a register or on the stack
-  if (SaveIsReg) {
-    // move $save, $gpreg
-    Inst.setOpcode(Mips::DADDu);
-    Inst.addOperand(MCOperand::CreateReg(Save));
-    Inst.addOperand(MCOperand::CreateReg(GPReg));
-    Inst.addOperand(MCOperand::CreateReg(getGPR(0)));
-  } else {
-    // sd $gpreg, offset($sp)
-    Inst.setOpcode(Mips::SD);
-    Inst.addOperand(MCOperand::CreateReg(GPReg));
-    Inst.addOperand(MCOperand::CreateReg(getGPR(matchCPURegisterName("sp"))));
-    Inst.addOperand(MCOperand::CreateImm(Save));
-  }
-  TS.EmitInstruction(Inst, STI);
-  Inst.clear();
-
-  const MCSymbolRefExpr *HiExpr = MCSymbolRefExpr::Create(
-      Sym->getName(), MCSymbolRefExpr::VK_Mips_GPOFF_HI, getContext());
-  const MCSymbolRefExpr *LoExpr = MCSymbolRefExpr::Create(
-      Sym->getName(), MCSymbolRefExpr::VK_Mips_GPOFF_LO, getContext());
-  // lui $gp, %hi(%neg(%gp_rel(funcSym)))
-  Inst.setOpcode(Mips::LUi);
-  Inst.addOperand(MCOperand::CreateReg(GPReg));
-  Inst.addOperand(MCOperand::CreateExpr(HiExpr));
-  TS.EmitInstruction(Inst, STI);
-  Inst.clear();
-
-  // addiu  $gp, $gp, %lo(%neg(%gp_rel(funcSym)))
-  Inst.setOpcode(Mips::ADDiu);
-  Inst.addOperand(MCOperand::CreateReg(GPReg));
-  Inst.addOperand(MCOperand::CreateReg(GPReg));
-  Inst.addOperand(MCOperand::CreateExpr(LoExpr));
-  TS.EmitInstruction(Inst, STI);
-  Inst.clear();
-
-  // daddu  $gp, $gp, $funcreg
-  Inst.setOpcode(Mips::DADDu);
-  Inst.addOperand(MCOperand::CreateReg(GPReg));
-  Inst.addOperand(MCOperand::CreateReg(GPReg));
-  Inst.addOperand(MCOperand::CreateReg(FuncReg));
-  TS.EmitInstruction(Inst, STI);
+  getTargetStreamer().emitDirectiveCpsetup(FuncReg, Save, *Sym, SaveIsReg);
   return false;
 }
 
 bool MipsAsmParser::parseDirectiveNaN() {
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     const AsmToken &Tok = Parser.getTok();
 
     if (Tok.getString() == "2008") {

lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp

void MipsTargetAsmStreamer::emitFMask(unsigned FPUBitmask,
   OS << "," << FPUTopSavedRegOff << '\n';
 }
 
 void MipsTargetAsmStreamer::emitDirectiveCpload(unsigned RegNo) {
   OS << "\t.cpload\t$"
      << StringRef(MipsInstPrinter::getRegisterName(RegNo)).lower() << "\n";
 }
 
+void MipsTargetAsmStreamer::emitDirectiveCpsetup(unsigned RegNo,
+                                                 int RegOrOffset,
+                                                 const MCSymbol &Sym,
+                                                 bool IsReg) {
+  OS << "\t.cpsetup\t$"
+     << StringRef(MipsInstPrinter::getRegisterName(RegNo)).lower() << ", ";
+
+  if (IsReg)
+    OS << "$"
+       << StringRef(MipsInstPrinter::getRegisterName(RegOrOffset)).lower();
+  else
+    OS << RegOrOffset;
+
+  OS << ", ";
+
+  OS << Sym.getName() << "\n";
+}
+
 // This part is for ELF object output.
 MipsTargetELFStreamer::MipsTargetELFStreamer(MCStreamer &S,
                                              const MCSubtargetInfo &STI)
     : MipsTargetStreamer(S), MicroMipsEnabled(false), STI(STI) {
   MCAssembler &MCA = getStreamer().getAssembler();
   uint64_t Features = STI.getFeatureBits();
   Triple T(STI.getTargetTriple());
   Pic = (MCA.getContext().getObjectFileInfo()->getRelocM() ==  Reloc::PIC_)
void MipsTargetELFStreamer::emitDirectiveCpload(unsigned RegNo) {
   TmpInst.clear();
 
   TmpInst.setOpcode(Mips::ADDu);
   TmpInst.addOperand(MCOperand::CreateReg(Mips::GP));
   TmpInst.addOperand(MCOperand::CreateReg(Mips::GP));
   TmpInst.addOperand(MCOperand::CreateReg(RegNo));
   getStreamer().EmitInstruction(TmpInst, STI);
 }
+
+void MipsTargetELFStreamer::emitDirectiveCpsetup(unsigned RegNo,
+                                                 int RegOrOffset,
+                                                 const MCSymbol &Sym,
+                                                 bool IsReg) {
+  // Only N32 and N64 emit anything for .cpsetup iff PIC is set.
+  if (!Pic || !(isN32() || isN64()))
+    return;
+
+  MCAssembler &MCA = getStreamer().getAssembler();
+  MCInst Inst;
+
+  // Either store the old $gp in a register or on the stack
+  if (IsReg) {
+    // move $save, $gpreg
+    Inst.setOpcode(Mips::DADDu);
+    Inst.addOperand(MCOperand::CreateReg(RegOrOffset));
+    Inst.addOperand(MCOperand::CreateReg(Mips::GP));
+    Inst.addOperand(MCOperand::CreateReg(Mips::ZERO));
+  } else {
+    // sd $gpreg, offset($sp)
+    Inst.setOpcode(Mips::SD);
+    Inst.addOperand(MCOperand::CreateReg(Mips::GP));
+    Inst.addOperand(MCOperand::CreateReg(Mips::SP));
+    Inst.addOperand(MCOperand::CreateImm(RegOrOffset));
+  }
+  getStreamer().EmitInstruction(Inst, STI);
+  Inst.clear();
+
+  const MCSymbolRefExpr *HiExpr = MCSymbolRefExpr::Create(
+      Sym.getName(), MCSymbolRefExpr::VK_Mips_GPOFF_HI, MCA.getContext());
+  const MCSymbolRefExpr *LoExpr = MCSymbolRefExpr::Create(
+      Sym.getName(), MCSymbolRefExpr::VK_Mips_GPOFF_LO, MCA.getContext());
+  // lui $gp, %hi(%neg(%gp_rel(funcSym)))
+  Inst.setOpcode(Mips::LUi);
+  Inst.addOperand(MCOperand::CreateReg(Mips::GP));
+  Inst.addOperand(MCOperand::CreateExpr(HiExpr));
+  getStreamer().EmitInstruction(Inst, STI);
+  Inst.clear();
+
+  // addiu  $gp, $gp, %lo(%neg(%gp_rel(funcSym)))
+  Inst.setOpcode(Mips::ADDiu);
+  Inst.addOperand(MCOperand::CreateReg(Mips::GP));
+  Inst.addOperand(MCOperand::CreateReg(Mips::GP));
+  Inst.addOperand(MCOperand::CreateExpr(LoExpr));
+  getStreamer().EmitInstruction(Inst, STI);
+  Inst.clear();
+
+  // daddu  $gp, $gp, $funcreg
+  Inst.setOpcode(Mips::DADDu);
+  Inst.addOperand(MCOperand::CreateReg(Mips::GP));
+  Inst.addOperand(MCOperand::CreateReg(Mips::GP));
+  Inst.addOperand(MCOperand::CreateReg(RegNo));
+  getStreamer().EmitInstruction(Inst, STI);
+}

lib/Target/Mips/MipsTargetStreamer.h

public:
 
   virtual void emitDirectiveSetMips32R2() = 0;
   virtual void emitDirectiveSetMips64() = 0;
   virtual void emitDirectiveSetMips64R2() = 0;
   virtual void emitDirectiveSetDsp() = 0;
 
   // PIC support
   virtual void emitDirectiveCpload(unsigned RegNo) = 0;
+  virtual void emitDirectiveCpsetup(unsigned RegNo, int RegOrOffset,
+                                    const MCSymbol &Sym, bool IsReg) = 0;
 };
 
 // This part is for ascii assembly output
 class MipsTargetAsmStreamer : public MipsTargetStreamer {
   formatted_raw_ostream &OS;
 
 public:
   MipsTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS);
public:
 
   void emitDirectiveSetMips32R2() override;
   void emitDirectiveSetMips64() override;
   void emitDirectiveSetMips64R2() override;
   void emitDirectiveSetDsp() override;
 
   // PIC support
   virtual void emitDirectiveCpload(unsigned RegNo);
+  void emitDirectiveCpsetup(unsigned RegNo, int RegOrOffset,
+                            const MCSymbol &Sym, bool IsReg) override;
 };
 
 // This part is for ELF object output
 class MipsTargetELFStreamer : public MipsTargetStreamer {
   bool MicroMipsEnabled;
   const MCSubtargetInfo &STI;
   bool Pic;
 
public:
 
   void emitDirectiveSetMips32R2() override;
   void emitDirectiveSetMips64() override;
   void emitDirectiveSetMips64R2() override;
   void emitDirectiveSetDsp() override;
 
   // PIC support
   virtual void emitDirectiveCpload(unsigned RegNo);
+  void emitDirectiveCpsetup(unsigned RegNo, int RegOrOffset,
+                            const MCSymbol &Sym, bool IsReg) override;
 
 protected:
   bool isO32() const { return STI.getFeatureBits() & Mips::FeatureO32; }
   bool isN32() const { return STI.getFeatureBits() & Mips::FeatureN32; }
   bool isN64() const { return STI.getFeatureBits() & Mips::FeatureN64; }
 };
 }
 #endif

test/MC/Mips/cpsetup.s

+# RUN: llvm-mc -triple mips64-unknown-unknown -mattr=-n64,+o32 -filetype=obj -o - %s | \
+# RUN:   llvm-objdump -d -r -arch=mips64 - | \
+# RUN:     FileCheck -check-prefix=O32 %s
+
 # RUN: llvm-mc -triple mips64-unknown-unknown -mattr=-n64,+o32 %s | \
-# RUN:     FileCheck -check-prefix=ANY -check-prefix=O32 %s
+# RUN:   FileCheck -check-prefix=ASM %s
+
+# RUN: llvm-mc -triple mips64-unknown-unknown -mattr=-n64,+n32 -filetype=obj -o - %s | \
+# RUN:   llvm-objdump -d -r -arch=mips64 - | \
+# RUN:     FileCheck -check-prefix=NXX -check-prefix=N32 %s
+
 # RUN: llvm-mc -triple mips64-unknown-unknown -mattr=-n64,+n32 %s | \
-# RUN:     FileCheck -check-prefix=ANY -check-prefix=NXX -check-prefix=N32 %s
-# RUN: llvm-mc -triple mips64-unknown-unknown %s | \
-# RUN:     FileCheck -check-prefix=ANY -check-prefix=NXX -check-prefix=N64 %s
+# RUN:   FileCheck -check-prefix=ASM %s
 
-# TODO: !PIC -> no output
+# RUN: llvm-mc -triple mips64-unknown-unknown %s -filetype=obj -o - | \
+# RUN:   llvm-objdump -d -r -arch=mips64 - | \
+# RUN:     FileCheck -check-prefix=NXX -check-prefix=N64 %s
+
+# RUN: llvm-mc -triple mips64-unknown-unknown %s | \
+# RUN:   FileCheck -check-prefix=ASM %s
 
         .text
         .option pic2
 t1:
         .cpsetup $25, 8, __cerror
 
-# ANY-LABEL: t1:
 
 # O32-NOT: __cerror
 
+# FIXME: Direct object emission for N32 is still under development.
+# N32 doesn't allow 3 operations to be specified in the same relocation
+# record like N64 does.
+
 # NXX: sd       $gp, 8($sp)
-# NXX: lui      $gp, %hi(%neg(%gp_rel(__cerror)))
-# NXX: addiu    $gp, $gp, %lo(%neg(%gp_rel(__cerror)))
+# NXX: lui      $gp, 0
+# NXX: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_HI16  __cerror
+# NXX: addiu    $gp, $gp, 0
+# NXX: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16  __cerror
 # N32: addu     $gp, $gp, $25
 # N64: daddu    $gp, $gp, $25
 
+# ASM: .cpsetup $25, 8, __cerror
+
 t2:
-# ANY-LABEL: t2:
 
         .cpsetup $25, $2, __cerror
 
 # O32-NOT: __cerror
 
+# FIXME: Direct object emission for N32 is still under development.
+# N32 doesn't allow 3 operations to be specified in the same relocation
+# record like N64 does.
+
 # NXX: move     $2, $gp
-# NXX: lui      $gp, %hi(%neg(%gp_rel(__cerror)))
-# NXX: addiu    $gp, $gp, %lo(%neg(%gp_rel(__cerror)))
+# NXX: lui      $gp, 0
+# NXX: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_HI16  __cerror
+# NXX: addiu    $gp, $gp, 0
+# NXX: R_MIPS_GPREL16/R_MIPS_SUB/R_MIPS_LO16  __cerror
 # N32: addu     $gp, $gp, $25
 # N64: daddu    $gp, $gp, $25
+
+# ASM: .cpsetup $25, $2, __cerror
+
+t3:
+        .option pic0
+        nop
+        .cpsetup $25, 8, __cerror
+        nop
+
+# Testing that .cpsetup expands to nothing in this case
+# by checking that the next instruction after the first
+# nop is also a 'nop'.
+# NXX: nop
+# NXX-NEXT: nop
+
+# ASM: nop
+# ASM: .cpsetup $25, 8, __cerror
+# ASM: nop