1 //===-- TargetOptionsImpl.cpp - Options that apply to all targets ----------==// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements the methods in the TargetOptions. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "llvm/CodeGen/MachineFrameInfo.h" 14 #include "llvm/CodeGen/MachineFunction.h" 15 #include "llvm/CodeGen/TargetFrameLowering.h" 16 #include "llvm/CodeGen/TargetSubtargetInfo.h" 17 #include "llvm/IR/Function.h" 18 #include "llvm/IR/Module.h" 19 #include "llvm/Target/TargetOptions.h" 20 using namespace llvm; 21 22 /// DisableFramePointerElim - This returns true if frame pointer elimination 23 /// optimization should be disabled for the given machine function. 24 bool TargetOptions::DisableFramePointerElim(const MachineFunction &MF) const { 25 // Check to see if the target want to forcably keep frame pointer. 26 if (MF.getSubtarget().getFrameLowering()->keepFramePointer(MF)) 27 return true; 28 29 const Function &F = MF.getFunction(); 30 31 // TODO: Remove support for old `fp elim` function attributes after fully 32 // migrate to use "frame-pointer" 33 if (!F.hasFnAttribute("frame-pointer")) { 34 // Check to see if we should eliminate all frame pointers. 35 if (F.getFnAttribute("no-frame-pointer-elim").getValueAsString() == "true") 36 return true; 37 38 // Check to see if we should eliminate non-leaf frame pointers. 39 if (F.hasFnAttribute("no-frame-pointer-elim-non-leaf")) 40 return MF.getFrameInfo().hasCalls(); 41 42 return false; 43 } 44 45 StringRef FP = F.getFnAttribute("frame-pointer").getValueAsString(); 46 if (FP == "all") 47 return true; 48 if (FP == "non-leaf") 49 return MF.getFrameInfo().hasCalls(); 50 if (FP == "none") 51 return false; 52 llvm_unreachable("unknown frame pointer flag"); 53 } 54 55 /// HonorSignDependentRoundingFPMath - Return true if the codegen must assume 56 /// that the rounding mode of the FPU can change from its default. 57 bool TargetOptions::HonorSignDependentRoundingFPMath() const { 58 return !UnsafeFPMath && HonorSignDependentRoundingFPMathOption; 59 } 60