1 // Copyright 2016, VIXL authors 2 // All rights reserved. 3 // 4 // Redistribution and use in source and binary forms, with or without 5 // modification, are permitted provided that the following conditions are met: 6 // 7 // * Redistributions of source code must retain the above copyright notice, 8 // this list of conditions and the following disclaimer. 9 // * Redistributions in binary form must reproduce the above copyright notice, 10 // this list of conditions and the following disclaimer in the documentation 11 // and/or other materials provided with the distribution. 12 // * Neither the name of ARM Limited nor the names of its contributors may be 13 // used to endorse or promote products derived from this software without 14 // specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND 17 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 18 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 19 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE 20 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 22 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 23 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 27 // The ABI features are only supported with C++11 or later. 28 #if __cplusplus >= 201103L 29 // This should not be defined manually. 30 #define VIXL_HAS_ABI_SUPPORT 31 #elif defined(VIXL_HAS_ABI_SUPPORT) 32 #error "The ABI support requires C++11 or later." 33 #endif 34 35 #ifdef VIXL_HAS_ABI_SUPPORT 36 37 #ifndef VIXL_AARCH64_ABI_AARCH64_H_ 38 #define VIXL_AARCH64_ABI_AARCH64_H_ 39 40 #include <algorithm> 41 #include <type_traits> 42 43 #include "../globals-vixl.h" 44 45 #include "instructions-aarch64.h" 46 #include "operands-aarch64.h" 47 48 namespace vixl { 49 namespace aarch64 { 50 51 // Class describing the AArch64 procedure call standard, as defined in "ARM 52 // Procedure Call Standard for the ARM 64-bit Architecture (AArch64)", 53 // release 1.0 (AAPCS below). 54 // 55 // The stages in the comments match the description in that document. 56 // 57 // Stage B does not apply to arguments handled by this class. 58 class ABI { 59 public: stack_pointer_(stack_pointer)60 explicit ABI(Register stack_pointer = sp) : stack_pointer_(stack_pointer) { 61 // Stage A - Initialization 62 Reset(); 63 } 64 Reset()65 void Reset() { 66 NGRN_ = 0; 67 NSRN_ = 0; 68 stack_offset_ = 0; 69 } 70 GetStackSpaceRequired()71 int GetStackSpaceRequired() { return stack_offset_; } 72 73 // The logic is described in section 5.5 of the AAPCS. 74 template <typename T> GetReturnGenericOperand()75 GenericOperand GetReturnGenericOperand() const { 76 ABI abi(stack_pointer_); 77 GenericOperand result = abi.GetNextParameterGenericOperand<T>(); 78 VIXL_ASSERT(result.IsCPURegister()); 79 return result; 80 } 81 82 // The logic is described in section 5.4.2 of the AAPCS. 83 // The `GenericOperand` returned describes the location reserved for the 84 // argument from the point of view of the callee. 85 template <typename T> GetNextParameterGenericOperand()86 GenericOperand GetNextParameterGenericOperand() { 87 const bool is_floating_point_type = std::is_floating_point<T>::value; 88 const bool is_integral_type = 89 std::is_integral<T>::value || std::is_enum<T>::value; 90 const bool is_pointer_type = std::is_pointer<T>::value; 91 int type_alignment = std::alignment_of<T>::value; 92 93 // We only support basic types. 94 VIXL_ASSERT(is_floating_point_type || is_integral_type || is_pointer_type); 95 96 // To ensure we get the correct type of operand when simulating on a 32-bit 97 // host, force the size of pointer types to the native AArch64 pointer size. 98 unsigned size = is_pointer_type ? 8 : sizeof(T); 99 // The size of the 'operand' reserved for the argument. 100 unsigned operand_size = AlignUp(size, kWRegSizeInBytes); 101 if (size > 8) { 102 VIXL_UNIMPLEMENTED(); 103 return GenericOperand(); 104 } 105 106 // Stage C.1 107 if (is_floating_point_type && (NSRN_ < 8)) { 108 return GenericOperand(VRegister(NSRN_++, size * kBitsPerByte)); 109 } 110 // Stages C.2, C.3, and C.4: Unsupported. Caught by the assertions above. 111 // Stages C.5 and C.6 112 if (is_floating_point_type) { 113 VIXL_STATIC_ASSERT( 114 !is_floating_point_type || 115 (std::is_same<T, float>::value || std::is_same<T, double>::value)); 116 int offset = stack_offset_; 117 stack_offset_ += 8; 118 return GenericOperand(MemOperand(stack_pointer_, offset), operand_size); 119 } 120 // Stage C.7 121 if ((is_integral_type || is_pointer_type) && (size <= 8) && (NGRN_ < 8)) { 122 return GenericOperand(Register(NGRN_++, operand_size * kBitsPerByte)); 123 } 124 // Stage C.8 125 if (type_alignment == 16) { 126 NGRN_ = AlignUp(NGRN_, 2); 127 } 128 // Stage C.9 129 if (is_integral_type && (size == 16) && (NGRN_ < 7)) { 130 VIXL_UNIMPLEMENTED(); 131 return GenericOperand(); 132 } 133 // Stage C.10: Unsupported. Caught by the assertions above. 134 // Stage C.11 135 NGRN_ = 8; 136 // Stage C.12 137 stack_offset_ = AlignUp(stack_offset_, std::max(type_alignment, 8)); 138 // Stage C.13: Unsupported. Caught by the assertions above. 139 // Stage C.14 140 VIXL_ASSERT(size <= 8u); 141 size = std::max(size, 8u); 142 int offset = stack_offset_; 143 stack_offset_ += size; 144 return GenericOperand(MemOperand(stack_pointer_, offset), operand_size); 145 } 146 147 private: 148 Register stack_pointer_; 149 // Next General-purpose Register Number. 150 int NGRN_; 151 // Next SIMD and Floating-point Register Number. 152 int NSRN_; 153 // The acronym "NSAA" used in the standard refers to the "Next Stacked 154 // Argument Address". Here we deal with offsets from the stack pointer. 155 int stack_offset_; 156 }; 157 158 template <> 159 inline GenericOperand ABI::GetReturnGenericOperand<void>() const { 160 return GenericOperand(); 161 } 162 } 163 } // namespace vixl::aarch64 164 165 #endif // VIXL_AARCH64_ABI_AARCH64_H_ 166 167 #endif // VIXL_HAS_ABI_SUPPORT 168