[mips] Add support for .cpload.
Summary:
This directive is used for setting up $gp in the beginning of a function.
It expands to three instructions if PIC is enabled:
lui $gp, %hi(_gp_disp)
addui $gp, $gp, %lo(_gp_disp)
addu $gp, $gp, $reg
_gp_disp is a special symbol that the linker sets to the distance between
the lui instruction and the context pointer (_gp).
Reviewers: dsanders
Reviewed By: dsanders
Differential Revision: http://reviews.llvm.org/D3480
llvm-svn: 207637
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
index 053e13e..ab1b1f6 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
@@ -144,6 +144,11 @@
OS << "," << FPUTopSavedRegOff << '\n';
}
+void MipsTargetAsmStreamer::emitDirectiveCpload(unsigned RegNo) {
+ OS << "\t.cpload\t$"
+ << StringRef(MipsInstPrinter::getRegisterName(RegNo)).lower() << "\n";
+}
+
// This part is for ELF object output.
MipsTargetELFStreamer::MipsTargetELFStreamer(MCStreamer &S,
const MCSubtargetInfo &STI)
@@ -402,3 +407,52 @@
void MipsTargetELFStreamer::emitDirectiveSetDsp() {
// No action required for ELF output.
}
+
+void MipsTargetELFStreamer::emitDirectiveCpload(unsigned RegNo) {
+ // .cpload $reg
+ // This directive expands to:
+ // lui $gp, %hi(_gp_disp)
+ // addui $gp, $gp, %lo(_gp_disp)
+ // addu $gp, $gp, $reg
+ // when support for position independent code is enabled.
+ if (!Pic || (isN32() || isN64()))
+ return;
+
+ // There's a GNU extension controlled by -mno-shared that allows
+ // locally-binding symbols to be accessed using absolute addresses.
+ // This is currently not supported. When supported -mno-shared makes
+ // .cpload expand to:
+ // lui $gp, %hi(__gnu_local_gp)
+ // addiu $gp, $gp, %lo(__gnu_local_gp)
+
+ StringRef SymName("_gp_disp");
+ MCAssembler &MCA = getStreamer().getAssembler();
+ MCSymbol *GP_Disp = MCA.getContext().GetOrCreateSymbol(SymName);
+ MCA.getOrCreateSymbolData(*GP_Disp);
+
+ MCInst TmpInst;
+ TmpInst.setOpcode(Mips::LUi);
+ TmpInst.addOperand(MCOperand::CreateReg(Mips::GP));
+ const MCSymbolRefExpr *HiSym = MCSymbolRefExpr::Create(
+ "_gp_disp", MCSymbolRefExpr::VK_Mips_ABS_HI, MCA.getContext());
+ TmpInst.addOperand(MCOperand::CreateExpr(HiSym));
+ getStreamer().EmitInstruction(TmpInst, STI);
+
+ TmpInst.clear();
+
+ TmpInst.setOpcode(Mips::ADDiu);
+ TmpInst.addOperand(MCOperand::CreateReg(Mips::GP));
+ TmpInst.addOperand(MCOperand::CreateReg(Mips::GP));
+ const MCSymbolRefExpr *LoSym = MCSymbolRefExpr::Create(
+ "_gp_disp", MCSymbolRefExpr::VK_Mips_ABS_LO, MCA.getContext());
+ TmpInst.addOperand(MCOperand::CreateExpr(LoSym));
+ getStreamer().EmitInstruction(TmpInst, STI);
+
+ 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);
+}