diff --git a/llvm/lib/Target/AArch64/AArch64FastISel.cpp b/llvm/lib/Target/AArch64/AArch64FastISel.cpp --- a/llvm/lib/Target/AArch64/AArch64FastISel.cpp +++ b/llvm/lib/Target/AArch64/AArch64FastISel.cpp @@ -496,6 +496,20 @@ ADRPReg) .addGlobalAddress(GV, 0, AArch64II::MO_PAGE | OpFlags); + if (OpFlags & AArch64II::MO_TAGGED) { + // MO_TAGGED on the page indicates a tagged address. Set the tag now. + // We do so by creating a MOVK that sets bits 48-63 of the register to + // (global address + 0x100000000 - PC) >> 48. This assumes that we're in + // the small code model so we can assume a binary size of <= 4GB, which + // makes the untagged PC relative offset positive. The binary must also be + // loaded into address range [0, 2^48). Both of these properties need to + // be ensured at runtime when using tagged addresses. + BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, MIMD, TII.get(AArch64::MOVKXi), ADRPReg) + .addReg(ADRPReg) + .addGlobalAddress(GV, /*Offset=*/0x100000000, AArch64II::MO_PREL | AArch64II::MO_G3) + .addImm(48); + } + ResultReg = createResultReg(&AArch64::GPR64spRegClass); BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, MIMD, TII.get(AArch64::ADDXri), ResultReg)