diff options
| -rw-r--r-- | lib/Target/AArch64/AArch64ISelLowering.cpp | 15 | ||||
| -rw-r--r-- | lib/Target/AArch64/AArch64InstrInfo.td | 6 | ||||
| -rw-r--r-- | test/CodeGen/AArch64/extern-weak.ll | 13 |
3 files changed, 30 insertions, 4 deletions
diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp index e2e472fa9f..071b432998 100644 --- a/lib/Target/AArch64/AArch64ISelLowering.cpp +++ b/lib/Target/AArch64/AArch64ISelLowering.cpp @@ -1863,7 +1863,7 @@ AArch64TargetLowering::LowerGlobalAddressELF(SDValue Op, // TableGen doesn't have easy access to the CodeModel or RelocationModel, so // we make that distinction here. - // We support the static, small memory model for now. + // We support the small memory model for now. assert(getTargetMachine().getCodeModel() == CodeModel::Small); EVT PtrVT = getPointerTy(); @@ -1871,6 +1871,18 @@ AArch64TargetLowering::LowerGlobalAddressELF(SDValue Op, const GlobalAddressSDNode *GN = cast<GlobalAddressSDNode>(Op); const GlobalValue *GV = GN->getGlobal(); unsigned Alignment = GV->getAlignment(); + Reloc::Model RelocM = getTargetMachine().getRelocationModel(); + + if (GV->isWeakForLinker() && RelocM == Reloc::Static) { + // Weak symbols can't use ADRP/ADD pair since they should evaluate to + // zero when undefined. In PIC mode the GOT can take care of this, but in + // absolute mode we use a constant pool load. + return DAG.getLoad(PtrVT, dl, DAG.getEntryNode(), + DAG.getConstantPool(GV, GN->getValueType(0)), + MachinePointerInfo::getConstantPool(), + /*isVolatile=*/ false, /*isNonTemporal=*/ true, + /*isInvariant=*/ true, 8); + } if (Alignment == 0) { const PointerType *GVPtrTy = cast<PointerType>(GV->getType()); @@ -1886,7 +1898,6 @@ AArch64TargetLowering::LowerGlobalAddressELF(SDValue Op, } unsigned char HiFixup, LoFixup; - Reloc::Model RelocM = getTargetMachine().getRelocationModel(); bool UseGOT = Subtarget->GVIsIndirectSymbol(GV, RelocM); if (UseGOT) { diff --git a/lib/Target/AArch64/AArch64InstrInfo.td b/lib/Target/AArch64/AArch64InstrInfo.td index 538d4bdb32..a9ff02ae0a 100644 --- a/lib/Target/AArch64/AArch64InstrInfo.td +++ b/lib/Target/AArch64/AArch64InstrInfo.td @@ -2409,8 +2409,10 @@ class A64I_LDRlitSimple<bits<2> opc, bit v, RegisterClass OutReg, "ldr\t$Rt, $Imm19", patterns, NoItinerary>; let mayLoad = 1 in { - def LDRw_lit : A64I_LDRlitSimple<0b00, 0b0, GPR32>; - def LDRx_lit : A64I_LDRlitSimple<0b01, 0b0, GPR64>; + def LDRw_lit : A64I_LDRlitSimple<0b00, 0b0, GPR32, + [(set (i32 GPR32:$Rt), (load constpool:$Imm19))]>; + def LDRx_lit : A64I_LDRlitSimple<0b01, 0b0, GPR64, + [(set (i64 GPR64:$Rt), (load constpool:$Imm19))]>; } def LDRs_lit : A64I_LDRlitSimple<0b00, 0b1, FPR32, diff --git a/test/CodeGen/AArch64/extern-weak.ll b/test/CodeGen/AArch64/extern-weak.ll new file mode 100644 index 0000000000..54baab2200 --- /dev/null +++ b/test/CodeGen/AArch64/extern-weak.ll @@ -0,0 +1,13 @@ +; RUN: llc -mtriple=aarch64-none-linux-gnu -o - < %s | FileCheck %s + +declare extern_weak i32 @var() + +define i32()* @foo() { +; The usual ADRP/ADD pair can't be used for a weak reference because it must +; evaluate to 0 if the symbol is undefined. We use a litpool entry. + ret i32()* @var +; CHECK: ldr x0, .LCPI0_0 + +; CHECK: .LCPI0_0: +; CHECK-NEXT: .xword var +} |