[mips] Pass "xgot" flag as a subtarget feature

We need "xgot" flag in the MipsAsmParser to implement correct expansion
of some pseudo instructions in case of using 32-bit GOT (XGOT).
MipsAsmParser does not have reference to MipsSubtarget but has a
reference to "feature bit set".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372220 91177308-0d34-0410-b5e6-96231b3b80d8

Author: atanasyan

lib/Target/Mips/Mips.td

@@ -209,6 +209,9 @@ def FeatureMT : SubtargetFeature<"mt", "HasMT", "true", "Mips MT ASE">;
 def FeatureLongCalls : SubtargetFeature<"long-calls", "UseLongCalls", "true",
                                         "Disable use of the jal instruction">;
 
+def FeatureXGOT
+    : SubtargetFeature<"xgot", "UseXGOT", "true", "Assume 32-bit GOT">;
+
 def FeatureUseIndirectJumpsHazard : SubtargetFeature<"use-indirect-jump-hazard",
                                                     "UseIndirectJumpsHazard",
                                                     "true", "Use indirect jump"

lib/Target/Mips/MipsISelLowering.cpp

@@ -82,10 +82,6 @@ using namespace llvm;
 
 STATISTIC(NumTailCalls, "Number of tail calls");
 
-static cl::opt<bool>
-LargeGOT("mxgot", cl::Hidden,
-         cl::desc("MIPS: Enable GOT larger than 64k."), cl::init(false));
-
 static cl::opt<bool>
 NoZeroDivCheck("mno-check-zero-division", cl::Hidden,
                cl::desc("MIPS: Don't trap on integer division by zero."),
@@ -554,8 +550,9 @@ MipsTargetLowering::createFastISel(FunctionLoweringInfo &funcInfo,
                      !Subtarget.inMicroMipsMode();
 
   // Disable if either of the following is true:
-  // We do not generate PIC, the ABI is not O32, LargeGOT is being used.
-  if (!TM.isPositionIndependent() || !TM.getABI().IsO32() || LargeGOT)
+  // We do not generate PIC, the ABI is not O32, XGOT is being used.
+  if (!TM.isPositionIndependent() || !TM.getABI().IsO32() ||
+      Subtarget.useXGOT())
     UseFastISel = false;
 
   return UseFastISel ? Mips::createFastISel(funcInfo, libInfo) : nullptr;
@@ -1989,7 +1986,7 @@ SDValue MipsTargetLowering::lowerGlobalAddress(SDValue Op,
   if (GV->hasLocalLinkage())
     return getAddrLocal(N, SDLoc(N), Ty, DAG, ABI.IsN32() || ABI.IsN64());
 
-  if (LargeGOT)
+  if (Subtarget.useXGOT())
     return getAddrGlobalLargeGOT(
         N, SDLoc(N), Ty, DAG, MipsII::MO_GOT_HI16, MipsII::MO_GOT_LO16,
         DAG.getEntryNode(),
@@ -3272,7 +3269,7 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
 
       if (InternalLinkage)
         Callee = getAddrLocal(G, DL, Ty, DAG, ABI.IsN32() || ABI.IsN64());
-      else if (LargeGOT) {
+      else if (Subtarget.useXGOT()) {
         Callee = getAddrGlobalLargeGOT(G, DL, Ty, DAG, MipsII::MO_CALL_HI16,
                                        MipsII::MO_CALL_LO16, Chain,
                                        FuncInfo->callPtrInfo(Val));
@@ -3294,7 +3291,7 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
     if (!IsPIC) // static
       Callee = DAG.getTargetExternalSymbol(
           Sym, getPointerTy(DAG.getDataLayout()), MipsII::MO_NO_FLAG);
-    else if (LargeGOT) {
+    else if (Subtarget.useXGOT()) {
       Callee = getAddrGlobalLargeGOT(S, DL, Ty, DAG, MipsII::MO_CALL_HI16,
                                      MipsII::MO_CALL_LO16, Chain,
                                      FuncInfo->callPtrInfo(Sym));

lib/Target/Mips/MipsSubtarget.h

@@ -189,6 +189,9 @@ class MipsSubtarget : public MipsGenSubtargetInfo {
   // Disable use of the `jal` instruction.
   bool UseLongCalls = false;
 
+  // Assume 32-bit GOT.
+  bool UseXGOT = false;
+
   /// The minimum alignment known to hold of the stack frame on
   /// entry to the function and which must be maintained by every function.
   unsigned stackAlignment;
@@ -323,6 +326,8 @@ class MipsSubtarget : public MipsGenSubtargetInfo {
 
   bool useLongCalls() const { return UseLongCalls; }
 
+  bool useXGOT() const { return UseXGOT; }
+
   bool enableLongBranchPass() const {
     return hasStandardEncoding() || inMicroMipsMode() || allowMixed16_32();
   }

test/CodeGen/Mips/address-selection.ll

@@ -1,8 +1,10 @@
 ; RUN: llc -march=mips < %s -debug 2>&1 | FileCheck %s --check-prefix=MIPS
-; RUN: llc -march=mips -relocation-model=pic -mxgot < %s -debug 2>&1 | FileCheck %s --check-prefix=MIPS-XGOT
+; RUN: llc -march=mips -relocation-model=pic -mattr=+xgot < %s \
+; RUN:     -debug 2>&1 | FileCheck %s --check-prefix=MIPS-XGOT
 
 ; RUN: llc -march=mips -mattr=+micromips < %s -debug 2>&1 | FileCheck %s --check-prefix=MM
-; RUN: llc -march=mips -relocation-model=pic -mxgot -mattr=+micromips < %s -debug 2>&1 | FileCheck %s --check-prefix=MM-XGOT
+; RUN: llc -march=mips -relocation-model=pic -mattr=+xgot,+micromips < %s \
+; RUN:     -debug 2>&1 | FileCheck %s --check-prefix=MM-XGOT
 
 ; REQUIRES: asserts
 

test/CodeGen/Mips/biggot.ll

@@ -1,9 +1,11 @@
-; RUN: llc -march=mipsel -mxgot -relocation-model=pic < %s | FileCheck %s -check-prefix=O32
-; RUN: llc -march=mips64el -mcpu=mips64r2 -mxgot -relocation-model=pic < %s | \
-; RUN: FileCheck %s -check-prefix=N64
-; RUN: llc -march=mipsel -mxgot -relocation-model=pic -fast-isel < %s | FileCheck %s -check-prefix=O32
-; RUN: llc -march=mips64el -mcpu=mips64r2 -mxgot -relocation-model=pic -fast-isel < %s | \
-; RUN: FileCheck %s -check-prefix=N64
+; RUN: llc -march=mipsel -mattr=+xgot \
+; RUN:     -relocation-model=pic < %s | FileCheck %s -check-prefix=O32
+; RUN: llc -march=mips64el -mcpu=mips64r2 -mattr=+xgot \
+; RUN:     -relocation-model=pic < %s | FileCheck %s -check-prefix=N64
+; RUN: llc -march=mipsel -mattr=+xgot -fast-isel \
+; RUN:     -relocation-model=pic < %s | FileCheck %s -check-prefix=O32
+; RUN: llc -march=mips64el -mcpu=mips64r2 -mattr=+xgot -fast-isel \
+; RUN:     -relocation-model=pic < %s | FileCheck %s -check-prefix=N64
 
 @v0 = external global i32
 

test/CodeGen/Mips/mirparser/target-flags-pic-mxgot-tls.mir

@@ -1,5 +1,5 @@
 # RUN: llc -march=mips64 -target-abi n64 -start-before=finalize-isel \
-# RUN:     -stop-after=finalize-isel -relocation-model=pic -mxgot \
+# RUN:     -stop-after=finalize-isel -relocation-model=pic -mattr=+xgot \
 # RUN:     -o /dev/null %s
 
 # A simple test to show that we can parse the target specific flags: gpoff-hi,