[PATCH] D66340: [RISCV] Support NonLazyBind

[Maxim Davydov via Phabricator via llvm-commits]

M_ximus created this revision.
M_ximus added reviewers: asb, lenary.
M_ximus added a project: LLVM.
Herald added subscribers: llvm-commits, s.egerton, Jim, benna, psnobl, jocewei, PkmX, rkruppe, the_o, brucehoult, MartinMosbeck, rogfer01, edward-jones, zzheng, MaskRay, jrtc27, shiva0217, kito-cheng, niosHD, sabuasal, apazos, simoncook, johnrusso, rbar, hiraditya.

This patch is needed to load call address from shared library without PLT(load from GOT).


Repository:
  rL LLVM

https://reviews.llvm.org/D66340

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/lib/Target/RISCV/RISCVSubtarget.cpp
  llvm/lib/Target/RISCV/RISCVSubtarget.h
  llvm/test/CodeGen/RISCV/no-plt.ll


Index: llvm/test/CodeGen/RISCV/no-plt.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/RISCV/no-plt.ll
@@ -0,0 +1,23 @@
+; RUN: llc -mtriple=riscv64-linux-gnu --relocation-model=pic < %s | FileCheck %s
+
+declare void @global() nonlazybind
+
+define void @no_PLT_call() nounwind {
+  ;CHECK-LABEL: no_PLT_call:
+
+  ;CHECK: # %bb.0:
+
+  ;CHECK-NEXT: addi sp, sp, -16
+  ;CHECK-NEXT: sd ra, 8(sp)
+
+  ;CHECK-NEXT: .LBB0_1: # Label of block must be emitted
+
+  ;CHECK-NEXT: auipc	a0, %got_pcrel_hi(global)
+  ;CHECK-NEXT: ld	a0, %pcrel_lo(.LBB0_1)(a0)
+  ;CHECK-NEXT: jalr	a0
+
+  ;CHECK-NEXT: ld	ra, 8(sp)
+
+  call void @global()
+  ret void
+}
Index: llvm/lib/Target/RISCV/RISCVSubtarget.h
===================================================================
--- llvm/lib/Target/RISCV/RISCVSubtarget.h
+++ llvm/lib/Target/RISCV/RISCVSubtarget.h
@@ -62,6 +62,11 @@
   // definition of this function is auto-generated by tblgen.
   void ParseSubtargetFeatures(StringRef CPU, StringRef FS);
 
+  /// Return how the function given by GV should be invoked:
+  /// via PLT, by taking its address from GOT, or with a direct call.
+  unsigned char classifyGlobalFunctionReference(const GlobalValue *GV,
+  						const TargetMachine &TM) const;
+
   const RISCVFrameLowering *getFrameLowering() const override {
     return &FrameLowering;
   }
Index: llvm/lib/Target/RISCV/RISCVSubtarget.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVSubtarget.cpp
+++ llvm/lib/Target/RISCV/RISCVSubtarget.cpp
@@ -48,3 +48,14 @@
     : RISCVGenSubtargetInfo(TT, CPU, FS),
       FrameLowering(initializeSubtargetDependencies(TT, CPU, FS, ABIName)),
       InstrInfo(), RegInfo(getHwMode()), TLInfo(TM, *this) {}
+
+unsigned char RISCVSubtarget::classifyGlobalFunctionReference(
+    const GlobalValue *GV, const TargetMachine &TM) const {
+  auto *F = dyn_cast<Function>(GV);
+  if (F && !TM.shouldAssumeDSOLocal(*GV->getParent(), GV)) {
+    if (F->hasFnAttribute(Attribute::NonLazyBind))
+      return RISCVII::MO_GOT_HI;
+    return RISCVII::MO_PLT;
+  }
+  return RISCVII::MO_CALL;
+}
Index: llvm/lib/Target/RISCV/RISCVISelLowering.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -2193,11 +2193,14 @@
   if (GlobalAddressSDNode *S = dyn_cast<GlobalAddressSDNode>(Callee)) {
     const GlobalValue *GV = S->getGlobal();
 
-    unsigned OpFlags = RISCVII::MO_CALL;
-    if (!getTargetMachine().shouldAssumeDSOLocal(*GV->getParent(), GV))
-      OpFlags = RISCVII::MO_PLT;
+    unsigned OpFlags =
+             Subtarget.classifyGlobalFunctionReference(GV, getTargetMachine());
+
+    if (OpFlags == RISCVII::MO_GOT_HI)
+      Callee = getAddr(S, DAG, 0);
+    else
+      Callee = DAG.getTargetGlobalAddress(GV, DL, PtrVT, 0, OpFlags);
 
-    Callee = DAG.getTargetGlobalAddress(GV, DL, PtrVT, 0, OpFlags);
   } else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee)) {
     unsigned OpFlags = RISCVII::MO_CALL;
 


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D66340.215559.patch
Type: text/x-patch
Size: 3151 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190816/61ae1feb/attachment.bin>