1 //===--- AArch64.cpp - AArch64 (not ARM) Helpers for Tools ------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "AArch64.h"
11 #include "clang/Driver/Driver.h"
12 #include "clang/Driver/DriverDiagnostic.h"
13 #include "clang/Driver/Options.h"
14 #include "llvm/Option/ArgList.h"
15 #include "llvm/Support/TargetParser.h"
16 
17 using namespace clang::driver;
18 using namespace clang::driver::tools;
19 using namespace clang;
20 using namespace llvm::opt;
21 
22 /// getAArch64TargetCPU - Get the (LLVM) name of the AArch64 cpu we are
23 /// targeting. Set \p A to the Arg corresponding to the -mcpu argument if it is
24 /// provided, or to nullptr otherwise.
25 std::string aarch64::getAArch64TargetCPU(const ArgList &Args, Arg *&A) {
26   std::string CPU;
27   // If we have -mcpu, use that.
28   if ((A = Args.getLastArg(options::OPT_mcpu_EQ))) {
29     StringRef Mcpu = A->getValue();
30     CPU = Mcpu.split("+").first.lower();
31   }
32 
33   // Handle CPU name is 'native'.
34   if (CPU == "native")
35     return llvm::sys::getHostCPUName();
36   else if (CPU.size())
37     return CPU;
38 
39   // Make sure we pick "cyclone" if -arch is used.
40   // FIXME: Should this be picked by checking the target triple instead?
41   if (Args.getLastArg(options::OPT_arch))
42     return "cyclone";
43 
44   return "generic";
45 }
46 
47 // Decode AArch64 features from string like +[no]featureA+[no]featureB+...
48 static bool DecodeAArch64Features(const Driver &D, StringRef text,
49                                   std::vector<StringRef> &Features) {
50   SmallVector<StringRef, 8> Split;
51   text.split(Split, StringRef("+"), -1, false);
52 
53   for (StringRef Feature : Split) {
54     StringRef FeatureName = llvm::AArch64::getArchExtFeature(Feature);
55     if (!FeatureName.empty())
56       Features.push_back(FeatureName);
57     else if (Feature == "neon" || Feature == "noneon")
58       D.Diag(clang::diag::err_drv_no_neon_modifier);
59     else
60       return false;
61   }
62   return true;
63 }
64 
65 // Check if the CPU name and feature modifiers in -mcpu are legal. If yes,
66 // decode CPU and feature.
67 static bool DecodeAArch64Mcpu(const Driver &D, StringRef Mcpu, StringRef &CPU,
68                               std::vector<StringRef> &Features) {
69   std::pair<StringRef, StringRef> Split = Mcpu.split("+");
70   CPU = Split.first;
71 
72   if (CPU == "generic") {
73     Features.push_back("+neon");
74   } else {
75     llvm::AArch64::ArchKind ArchKind = llvm::AArch64::parseCPUArch(CPU);
76     if (!llvm::AArch64::getArchFeatures(ArchKind, Features))
77       return false;
78 
79     unsigned Extension = llvm::AArch64::getDefaultExtensions(CPU, ArchKind);
80     if (!llvm::AArch64::getExtensionFeatures(Extension, Features))
81       return false;
82    }
83 
84   if (Split.second.size() && !DecodeAArch64Features(D, Split.second, Features))
85     return false;
86 
87   return true;
88 }
89 
90 static bool
91 getAArch64ArchFeaturesFromMarch(const Driver &D, StringRef March,
92                                 const ArgList &Args,
93                                 std::vector<StringRef> &Features) {
94   std::string MarchLowerCase = March.lower();
95   std::pair<StringRef, StringRef> Split = StringRef(MarchLowerCase).split("+");
96 
97   llvm::AArch64::ArchKind ArchKind = llvm::AArch64::parseArch(Split.first);
98   if (ArchKind == llvm::AArch64::ArchKind::INVALID ||
99       !llvm::AArch64::getArchFeatures(ArchKind, Features) ||
100       (Split.second.size() && !DecodeAArch64Features(D, Split.second, Features)))
101     return false;
102 
103   return true;
104 }
105 
106 static bool
107 getAArch64ArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,
108                                const ArgList &Args,
109                                std::vector<StringRef> &Features) {
110   StringRef CPU;
111   std::string McpuLowerCase = Mcpu.lower();
112   if (!DecodeAArch64Mcpu(D, McpuLowerCase, CPU, Features))
113     return false;
114 
115   return true;
116 }
117 
118 static bool
119 getAArch64MicroArchFeaturesFromMtune(const Driver &D, StringRef Mtune,
120                                      const ArgList &Args,
121                                      std::vector<StringRef> &Features) {
122   std::string MtuneLowerCase = Mtune.lower();
123   // Check CPU name is valid
124   std::vector<StringRef> MtuneFeatures;
125   StringRef Tune;
126   if (!DecodeAArch64Mcpu(D, MtuneLowerCase, Tune, MtuneFeatures))
127     return false;
128 
129   // Handle CPU name is 'native'.
130   if (MtuneLowerCase == "native")
131     MtuneLowerCase = llvm::sys::getHostCPUName();
132   if (MtuneLowerCase == "cyclone") {
133     Features.push_back("+zcm");
134     Features.push_back("+zcz");
135   }
136   return true;
137 }
138 
139 static bool
140 getAArch64MicroArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,
141                                     const ArgList &Args,
142                                     std::vector<StringRef> &Features) {
143   StringRef CPU;
144   std::vector<StringRef> DecodedFeature;
145   std::string McpuLowerCase = Mcpu.lower();
146   if (!DecodeAArch64Mcpu(D, McpuLowerCase, CPU, DecodedFeature))
147     return false;
148 
149   return getAArch64MicroArchFeaturesFromMtune(D, CPU, Args, Features);
150 }
151 
152 void aarch64::getAArch64TargetFeatures(const Driver &D, const ArgList &Args,
153                                        std::vector<StringRef> &Features) {
154   Arg *A;
155   bool success = true;
156   // Enable NEON by default.
157   Features.push_back("+neon");
158   if ((A = Args.getLastArg(options::OPT_march_EQ)))
159     success = getAArch64ArchFeaturesFromMarch(D, A->getValue(), Args, Features);
160   else if ((A = Args.getLastArg(options::OPT_mcpu_EQ)))
161     success = getAArch64ArchFeaturesFromMcpu(D, A->getValue(), Args, Features);
162   else if (Args.hasArg(options::OPT_arch))
163     success = getAArch64ArchFeaturesFromMcpu(D, getAArch64TargetCPU(Args, A),
164                                              Args, Features);
165 
166   if (success && (A = Args.getLastArg(clang::driver::options::OPT_mtune_EQ)))
167     success =
168         getAArch64MicroArchFeaturesFromMtune(D, A->getValue(), Args, Features);
169   else if (success && (A = Args.getLastArg(options::OPT_mcpu_EQ)))
170     success =
171         getAArch64MicroArchFeaturesFromMcpu(D, A->getValue(), Args, Features);
172   else if (success && Args.hasArg(options::OPT_arch))
173     success = getAArch64MicroArchFeaturesFromMcpu(
174         D, getAArch64TargetCPU(Args, A), Args, Features);
175 
176   if (!success)
177     D.Diag(diag::err_drv_clang_unsupported) << A->getAsString(Args);
178 
179   if (Args.getLastArg(options::OPT_mgeneral_regs_only)) {
180     Features.push_back("-fp-armv8");
181     Features.push_back("-crypto");
182     Features.push_back("-neon");
183   }
184 
185   // En/disable crc
186   if (Arg *A = Args.getLastArg(options::OPT_mcrc, options::OPT_mnocrc)) {
187     if (A->getOption().matches(options::OPT_mcrc))
188       Features.push_back("+crc");
189     else
190       Features.push_back("-crc");
191   }
192 
193   if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
194                                options::OPT_munaligned_access))
195     if (A->getOption().matches(options::OPT_mno_unaligned_access))
196       Features.push_back("+strict-align");
197 
198   if (Args.hasArg(options::OPT_ffixed_x18))
199     Features.push_back("+reserve-x18");
200 
201   if (Args.hasArg(options::OPT_mno_neg_immediates))
202     Features.push_back("+no-neg-immediates");
203 }
204