1 //===--- AVR.cpp - AVR ToolChain Implementations ----------------*- C++ -*-===//
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 #include "AVR.h"
10 #include "CommonArgs.h"
11 #include "clang/Driver/Compilation.h"
12 #include "clang/Driver/DriverDiagnostic.h"
13 #include "clang/Driver/InputInfo.h"
14 #include "clang/Driver/Options.h"
15 #include "llvm/ADT/StringExtras.h"
16 #include "llvm/MC/MCSubtargetInfo.h"
17 #include "llvm/Option/ArgList.h"
18 #include "llvm/Support/FileSystem.h"
19 #include "llvm/Support/Path.h"
20 #include "llvm/TargetParser/SubtargetFeature.h"
21 
22 using namespace clang::driver;
23 using namespace clang::driver::toolchains;
24 using namespace clang::driver::tools;
25 using namespace clang;
26 using namespace llvm::opt;
27 
28 namespace {
29 
30 // NOTE: This list has been synchronized with gcc-avr 7.3.0 and avr-libc 2.0.0.
31 constexpr struct {
32   StringRef Name;
33   StringRef SubPath;
34   StringRef Family;
35   unsigned DataAddr;
36 } MCUInfo[] = {
37     {"at90s1200", "", "avr1", 0},
38     {"attiny11", "", "avr1", 0},
39     {"attiny12", "", "avr1", 0},
40     {"attiny15", "", "avr1", 0},
41     {"attiny28", "", "avr1", 0},
42     {"at90s2313", "tiny-stack", "avr2", 0x800060},
43     {"at90s2323", "tiny-stack", "avr2", 0x800060},
44     {"at90s2333", "tiny-stack", "avr2", 0x800060},
45     {"at90s2343", "tiny-stack", "avr2", 0x800060},
46     {"at90s4433", "tiny-stack", "avr2", 0x800060},
47     {"attiny22", "tiny-stack", "avr2", 0x800060},
48     {"attiny26", "tiny-stack", "avr2", 0x800060},
49     {"at90s4414", "", "avr2", 0x800060},
50     {"at90s4434", "", "avr2", 0x800060},
51     {"at90s8515", "", "avr2", 0x800060},
52     {"at90c8534", "", "avr2", 0x800060},
53     {"at90s8535", "", "avr2", 0x800060},
54     {"attiny13", "avr25/tiny-stack", "avr25", 0x800060},
55     {"attiny13a", "avr25/tiny-stack", "avr25", 0x800060},
56     {"attiny2313", "avr25/tiny-stack", "avr25", 0x800060},
57     {"attiny2313a", "avr25/tiny-stack", "avr25", 0x800060},
58     {"attiny24", "avr25/tiny-stack", "avr25", 0x800060},
59     {"attiny24a", "avr25/tiny-stack", "avr25", 0x800060},
60     {"attiny25", "avr25/tiny-stack", "avr25", 0x800060},
61     {"attiny261", "avr25/tiny-stack", "avr25", 0x800060},
62     {"attiny261a", "avr25/tiny-stack", "avr25", 0x800060},
63     {"at86rf401", "avr25", "avr25", 0x800060},
64     {"ata5272", "avr25", "avr25", 0x800100},
65     {"ata6616c", "avr25", "avr25", 0x800100},
66     {"attiny4313", "avr25", "avr25", 0x800060},
67     {"attiny44", "avr25", "avr25", 0x800060},
68     {"attiny44a", "avr25", "avr25", 0x800060},
69     {"attiny84", "avr25", "avr25", 0x800060},
70     {"attiny84a", "avr25", "avr25", 0x800060},
71     {"attiny45", "avr25", "avr25", 0x800060},
72     {"attiny85", "avr25", "avr25", 0x800060},
73     {"attiny441", "avr25", "avr25", 0x800100},
74     {"attiny461", "avr25", "avr25", 0x800060},
75     {"attiny461a", "avr25", "avr25", 0x800060},
76     {"attiny841", "avr25", "avr25", 0x800100},
77     {"attiny861", "avr25", "avr25", 0x800060},
78     {"attiny861a", "avr25", "avr25", 0x800060},
79     {"attiny87", "avr25", "avr25", 0x800100},
80     {"attiny43u", "avr25", "avr25", 0x800060},
81     {"attiny48", "avr25", "avr25", 0x800100},
82     {"attiny88", "avr25", "avr25", 0x800100},
83     {"attiny828", "avr25", "avr25", 0x800100},
84     {"at43usb355", "avr3", "avr3", 0x800100},
85     {"at76c711", "avr3", "avr3", 0x800060},
86     {"atmega103", "avr31", "avr31", 0x800060},
87     {"at43usb320", "avr31", "avr31", 0x800060},
88     {"attiny167", "avr35", "avr35", 0x800100},
89     {"at90usb82", "avr35", "avr35", 0x800100},
90     {"at90usb162", "avr35", "avr35", 0x800100},
91     {"ata5505", "avr35", "avr35", 0x800100},
92     {"ata6617c", "avr35", "avr35", 0x800100},
93     {"ata664251", "avr35", "avr35", 0x800100},
94     {"atmega8u2", "avr35", "avr35", 0x800100},
95     {"atmega16u2", "avr35", "avr35", 0x800100},
96     {"atmega32u2", "avr35", "avr35", 0x800100},
97     {"attiny1634", "avr35", "avr35", 0x800100},
98     {"atmega8", "avr4", "avr4", 0x800060},
99     {"ata6289", "avr4", "avr4", 0x800100},
100     {"atmega8a", "avr4", "avr4", 0x800060},
101     {"ata6285", "avr4", "avr4", 0x800100},
102     {"ata6286", "avr4", "avr4", 0x800100},
103     {"ata6612c", "avr4", "avr4", 0x800100},
104     {"atmega48", "avr4", "avr4", 0x800100},
105     {"atmega48a", "avr4", "avr4", 0x800100},
106     {"atmega48pa", "avr4", "avr4", 0x800100},
107     {"atmega48pb", "avr4", "avr4", 0x800100},
108     {"atmega48p", "avr4", "avr4", 0x800100},
109     {"atmega88", "avr4", "avr4", 0x800100},
110     {"atmega88a", "avr4", "avr4", 0x800100},
111     {"atmega88p", "avr4", "avr4", 0x800100},
112     {"atmega88pa", "avr4", "avr4", 0x800100},
113     {"atmega88pb", "avr4", "avr4", 0x800100},
114     {"atmega8515", "avr4", "avr4", 0x800060},
115     {"atmega8535", "avr4", "avr4", 0x800060},
116     {"atmega8hva", "avr4", "avr4", 0x800100},
117     {"at90pwm1", "avr4", "avr4", 0x800100},
118     {"at90pwm2", "avr4", "avr4", 0x800100},
119     {"at90pwm2b", "avr4", "avr4", 0x800100},
120     {"at90pwm3", "avr4", "avr4", 0x800100},
121     {"at90pwm3b", "avr4", "avr4", 0x800100},
122     {"at90pwm81", "avr4", "avr4", 0x800100},
123     {"ata5702m322", "avr5", "avr5", 0x800200},
124     {"ata5782", "avr5", "avr5", 0x800200},
125     {"ata5790", "avr5", "avr5", 0x800100},
126     {"ata5790n", "avr5", "avr5", 0x800100},
127     {"ata5791", "avr5", "avr5", 0x800100},
128     {"ata5795", "avr5", "avr5", 0x800100},
129     {"ata5831", "avr5", "avr5", 0x800200},
130     {"ata6613c", "avr5", "avr5", 0x800100},
131     {"ata6614q", "avr5", "avr5", 0x800100},
132     {"ata8210", "avr5", "avr5", 0x800200},
133     {"ata8510", "avr5", "avr5", 0x800200},
134     {"atmega16", "avr5", "avr5", 0x800060},
135     {"atmega16a", "avr5", "avr5", 0x800060},
136     {"atmega161", "avr5", "avr5", 0x800060},
137     {"atmega162", "avr5", "avr5", 0x800100},
138     {"atmega163", "avr5", "avr5", 0x800060},
139     {"atmega164a", "avr5", "avr5", 0x800100},
140     {"atmega164p", "avr5", "avr5", 0x800100},
141     {"atmega164pa", "avr5", "avr5", 0x800100},
142     {"atmega165", "avr5", "avr5", 0x800100},
143     {"atmega165a", "avr5", "avr5", 0x800100},
144     {"atmega165p", "avr5", "avr5", 0x800100},
145     {"atmega165pa", "avr5", "avr5", 0x800100},
146     {"atmega168", "avr5", "avr5", 0x800100},
147     {"atmega168a", "avr5", "avr5", 0x800100},
148     {"atmega168p", "avr5", "avr5", 0x800100},
149     {"atmega168pa", "avr5", "avr5", 0x800100},
150     {"atmega168pb", "avr5", "avr5", 0x800100},
151     {"atmega169", "avr5", "avr5", 0x800100},
152     {"atmega169a", "avr5", "avr5", 0x800100},
153     {"atmega169p", "avr5", "avr5", 0x800100},
154     {"atmega169pa", "avr5", "avr5", 0x800100},
155     {"atmega32", "avr5", "avr5", 0x800060},
156     {"atmega32a", "avr5", "avr5", 0x800060},
157     {"atmega323", "avr5", "avr5", 0x800060},
158     {"atmega324a", "avr5", "avr5", 0x800100},
159     {"atmega324p", "avr5", "avr5", 0x800100},
160     {"atmega324pa", "avr5", "avr5", 0x800100},
161     {"atmega324pb", "avr5", "avr5", 0x800100},
162     {"atmega325", "avr5", "avr5", 0x800100},
163     {"atmega325a", "avr5", "avr5", 0x800100},
164     {"atmega325p", "avr5", "avr5", 0x800100},
165     {"atmega325pa", "avr5", "avr5", 0x800100},
166     {"atmega3250", "avr5", "avr5", 0x800100},
167     {"atmega3250a", "avr5", "avr5", 0x800100},
168     {"atmega3250p", "avr5", "avr5", 0x800100},
169     {"atmega3250pa", "avr5", "avr5", 0x800100},
170     {"atmega328", "avr5", "avr5", 0x800100},
171     {"atmega328p", "avr5", "avr5", 0x800100},
172     {"atmega328pb", "avr5", "avr5", 0x800100},
173     {"atmega329", "avr5", "avr5", 0x800100},
174     {"atmega329a", "avr5", "avr5", 0x800100},
175     {"atmega329p", "avr5", "avr5", 0x800100},
176     {"atmega329pa", "avr5", "avr5", 0x800100},
177     {"atmega3290", "avr5", "avr5", 0x800100},
178     {"atmega3290a", "avr5", "avr5", 0x800100},
179     {"atmega3290p", "avr5", "avr5", 0x800100},
180     {"atmega3290pa", "avr5", "avr5", 0x800100},
181     {"atmega406", "avr5", "avr5", 0x800100},
182     {"atmega64", "avr5", "avr5", 0x800100},
183     {"atmega64a", "avr5", "avr5", 0x800100},
184     {"atmega640", "avr5", "avr5", 0x800200},
185     {"atmega644", "avr5", "avr5", 0x800100},
186     {"atmega644a", "avr5", "avr5", 0x800100},
187     {"atmega644p", "avr5", "avr5", 0x800100},
188     {"atmega644pa", "avr5", "avr5", 0x800100},
189     {"atmega645", "avr5", "avr5", 0x800100},
190     {"atmega645a", "avr5", "avr5", 0x800100},
191     {"atmega645p", "avr5", "avr5", 0x800100},
192     {"atmega649", "avr5", "avr5", 0x800100},
193     {"atmega649a", "avr5", "avr5", 0x800100},
194     {"atmega649p", "avr5", "avr5", 0x800100},
195     {"atmega6450", "avr5", "avr5", 0x800100},
196     {"atmega6450a", "avr5", "avr5", 0x800100},
197     {"atmega6450p", "avr5", "avr5", 0x800100},
198     {"atmega6490", "avr5", "avr5", 0x800100},
199     {"atmega6490a", "avr5", "avr5", 0x800100},
200     {"atmega6490p", "avr5", "avr5", 0x800100},
201     {"atmega64rfr2", "avr5", "avr5", 0x800200},
202     {"atmega644rfr2", "avr5", "avr5", 0x800200},
203     {"atmega16hva", "avr5", "avr5", 0x800100},
204     {"atmega16hva2", "avr5", "avr5", 0x800100},
205     {"atmega16hvb", "avr5", "avr5", 0x800100},
206     {"atmega16hvbrevb", "avr5", "avr5", 0x800100},
207     {"atmega32hvb", "avr5", "avr5", 0x800100},
208     {"atmega32hvbrevb", "avr5", "avr5", 0x800100},
209     {"atmega64hve", "avr5", "avr5", 0x800100},
210     {"atmega64hve2", "avr5", "avr5", 0x800100},
211     {"at90can32", "avr5", "avr5", 0x800100},
212     {"at90can64", "avr5", "avr5", 0x800100},
213     {"at90pwm161", "avr5", "avr5", 0x800100},
214     {"at90pwm216", "avr5", "avr5", 0x800100},
215     {"at90pwm316", "avr5", "avr5", 0x800100},
216     {"atmega32c1", "avr5", "avr5", 0x800100},
217     {"atmega64c1", "avr5", "avr5", 0x800100},
218     {"atmega16m1", "avr5", "avr5", 0x800100},
219     {"atmega32m1", "avr5", "avr5", 0x800100},
220     {"atmega64m1", "avr5", "avr5", 0x800100},
221     {"atmega16u4", "avr5", "avr5", 0x800100},
222     {"atmega32u4", "avr5", "avr5", 0x800100},
223     {"atmega32u6", "avr5", "avr5", 0x800100},
224     {"at90usb646", "avr5", "avr5", 0x800100},
225     {"at90usb647", "avr5", "avr5", 0x800100},
226     {"at90scr100", "avr5", "avr5", 0x800100},
227     {"at94k", "avr5", "avr5", 0x800060},
228     {"m3000", "avr5", "avr5", 0x800060},
229     {"atmega128", "avr51", "avr51", 0x800100},
230     {"atmega128a", "avr51", "avr51", 0x800100},
231     {"atmega1280", "avr51", "avr51", 0x800200},
232     {"atmega1281", "avr51", "avr51", 0x800200},
233     {"atmega1284", "avr51", "avr51", 0x800100},
234     {"atmega1284p", "avr51", "avr51", 0x800100},
235     {"atmega128rfa1", "avr51", "avr51", 0x800200},
236     {"atmega128rfr2", "avr51", "avr51", 0x800200},
237     {"atmega1284rfr2", "avr51", "avr51", 0x800200},
238     {"at90can128", "avr51", "avr51", 0x800200},
239     {"at90usb1286", "avr51", "avr51", 0x800200},
240     {"at90usb1287", "avr51", "avr51", 0x800200},
241     {"atmega2560", "avr6", "avr6", 0x800200},
242     {"atmega2561", "avr6", "avr6", 0x800200},
243     {"atmega256rfr2", "avr6", "avr6", 0x800200},
244     {"atmega2564rfr2", "avr6", "avr6", 0x800200},
245     {"attiny4", "avrtiny", "avrtiny", 0x800040},
246     {"attiny5", "avrtiny", "avrtiny", 0x800040},
247     {"attiny9", "avrtiny", "avrtiny", 0x800040},
248     {"attiny10", "avrtiny", "avrtiny", 0x800040},
249     {"attiny20", "avrtiny", "avrtiny", 0x800040},
250     {"attiny40", "avrtiny", "avrtiny", 0x800040},
251     {"attiny102", "avrtiny", "avrtiny", 0x800040},
252     {"attiny104", "avrtiny", "avrtiny", 0x800040},
253     {"atxmega16a4", "avrxmega2", "avrxmega2", 0x802000},
254     {"atxmega16a4u", "avrxmega2", "avrxmega2", 0x802000},
255     {"atxmega16c4", "avrxmega2", "avrxmega2", 0x802000},
256     {"atxmega16d4", "avrxmega2", "avrxmega2", 0x802000},
257     {"atxmega32a4", "avrxmega2", "avrxmega2", 0x802000},
258     {"atxmega32a4u", "avrxmega2", "avrxmega2", 0x802000},
259     {"atxmega32c3", "avrxmega2", "avrxmega2", 0x802000},
260     {"atxmega32c4", "avrxmega2", "avrxmega2", 0x802000},
261     {"atxmega32d3", "avrxmega2", "avrxmega2", 0x802000},
262     {"atxmega32d4", "avrxmega2", "avrxmega2", 0x802000},
263     {"atxmega32e5", "avrxmega2", "avrxmega2", 0x802000},
264     {"atxmega16e5", "avrxmega2", "avrxmega2", 0x802000},
265     {"atxmega8e5", "avrxmega2", "avrxmega2", 0x802000},
266     {"atxmega64a3", "avrxmega4", "avrxmega4", 0x802000},
267     {"atxmega64a3u", "avrxmega4", "avrxmega4", 0x802000},
268     {"atxmega64a4u", "avrxmega4", "avrxmega4", 0x802000},
269     {"atxmega64b1", "avrxmega4", "avrxmega4", 0x802000},
270     {"atxmega64b3", "avrxmega4", "avrxmega4", 0x802000},
271     {"atxmega64c3", "avrxmega4", "avrxmega4", 0x802000},
272     {"atxmega64d3", "avrxmega4", "avrxmega4", 0x802000},
273     {"atxmega64d4", "avrxmega4", "avrxmega4", 0x802000},
274     {"atxmega64a1", "avrxmega5", "avrxmega5", 0x802000},
275     {"atxmega64a1u", "avrxmega5", "avrxmega5", 0x802000},
276     {"atxmega128a3", "avrxmega6", "avrxmega6", 0x802000},
277     {"atxmega128a3u", "avrxmega6", "avrxmega6", 0x802000},
278     {"atxmega128b1", "avrxmega6", "avrxmega6", 0x802000},
279     {"atxmega128b3", "avrxmega6", "avrxmega6", 0x802000},
280     {"atxmega128c3", "avrxmega6", "avrxmega6", 0x802000},
281     {"atxmega128d3", "avrxmega6", "avrxmega6", 0x802000},
282     {"atxmega128d4", "avrxmega6", "avrxmega6", 0x802000},
283     {"atxmega192a3", "avrxmega6", "avrxmega6", 0x802000},
284     {"atxmega192a3u", "avrxmega6", "avrxmega6", 0x802000},
285     {"atxmega192c3", "avrxmega6", "avrxmega6", 0x802000},
286     {"atxmega192d3", "avrxmega6", "avrxmega6", 0x802000},
287     {"atxmega256a3", "avrxmega6", "avrxmega6", 0x802000},
288     {"atxmega256a3u", "avrxmega6", "avrxmega6", 0x802000},
289     {"atxmega256a3b", "avrxmega6", "avrxmega6", 0x802000},
290     {"atxmega256a3bu", "avrxmega6", "avrxmega6", 0x802000},
291     {"atxmega256c3", "avrxmega6", "avrxmega6", 0x802000},
292     {"atxmega256d3", "avrxmega6", "avrxmega6", 0x802000},
293     {"atxmega384c3", "avrxmega6", "avrxmega6", 0x802000},
294     {"atxmega384d3", "avrxmega6", "avrxmega6", 0x802000},
295     {"atxmega128a1", "avrxmega7", "avrxmega7", 0x802000},
296     {"atxmega128a1u", "avrxmega7", "avrxmega7", 0x802000},
297     {"atxmega128a4u", "avrxmega7", "avrxmega7", 0x802000},
298     {"attiny202", "avrxmega3/short-calls", "avrxmega3", 0x803F80},
299     {"attiny204", "avrxmega3/short-calls", "avrxmega3", 0x803F80},
300     {"attiny212", "avrxmega3/short-calls", "avrxmega3", 0x803F80},
301     {"attiny214", "avrxmega3/short-calls", "avrxmega3", 0x803F80},
302     {"attiny402", "avrxmega3/short-calls", "avrxmega3", 0x803F00},
303     {"attiny404", "avrxmega3/short-calls", "avrxmega3", 0x803F00},
304     {"attiny406", "avrxmega3/short-calls", "avrxmega3", 0x803F00},
305     {"attiny412", "avrxmega3/short-calls", "avrxmega3", 0x803F00},
306     {"attiny414", "avrxmega3/short-calls", "avrxmega3", 0x803F00},
307     {"attiny416", "avrxmega3/short-calls", "avrxmega3", 0x803F00},
308     {"attiny417", "avrxmega3/short-calls", "avrxmega3", 0x803F00},
309     {"attiny804", "avrxmega3/short-calls", "avrxmega3", 0x803E00},
310     {"attiny806", "avrxmega3/short-calls", "avrxmega3", 0x803E00},
311     {"attiny807", "avrxmega3/short-calls", "avrxmega3", 0x803E00},
312     {"attiny814", "avrxmega3/short-calls", "avrxmega3", 0x803E00},
313     {"attiny816", "avrxmega3/short-calls", "avrxmega3", 0x803E00},
314     {"attiny817", "avrxmega3/short-calls", "avrxmega3", 0x803E00},
315     {"atmega808", "avrxmega3/short-calls", "avrxmega3", 0x803C00},
316     {"atmega809", "avrxmega3/short-calls", "avrxmega3", 0x803C00},
317     {"atmega1608", "avrxmega3", "avrxmega3", 0x803800},
318     {"atmega1609", "avrxmega3", "avrxmega3", 0x803800},
319     {"atmega3208", "avrxmega3", "avrxmega3", 0x803000},
320     {"atmega3209", "avrxmega3", "avrxmega3", 0x803000},
321     {"atmega4808", "avrxmega3", "avrxmega3", 0x802800},
322     {"atmega4809", "avrxmega3", "avrxmega3", 0x802800},
323     {"attiny1604", "avrxmega3", "avrxmega3", 0x803C00},
324     {"attiny1606", "avrxmega3", "avrxmega3", 0x803C00},
325     {"attiny1607", "avrxmega3", "avrxmega3", 0x803C00},
326     {"attiny1614", "avrxmega3", "avrxmega3", 0x803800},
327     {"attiny1616", "avrxmega3", "avrxmega3", 0x803800},
328     {"attiny1617", "avrxmega3", "avrxmega3", 0x803800},
329     {"attiny1624", "avrxmega3", "avrxmega3", 0x803800},
330     {"attiny1626", "avrxmega3", "avrxmega3", 0x803800},
331     {"attiny1627", "avrxmega3", "avrxmega3", 0x803800},
332     {"attiny3216", "avrxmega3", "avrxmega3", 0x803800},
333     {"attiny3217", "avrxmega3", "avrxmega3", 0x803800},
334 };
335 
336 std::string GetMCUSubPath(StringRef MCUName) {
337   for (const auto &MCU : MCUInfo)
338     if (MCU.Name == MCUName)
339       return std::string(MCU.SubPath);
340   return "";
341 }
342 
343 std::optional<StringRef> GetMCUFamilyName(StringRef MCUName) {
344   for (const auto &MCU : MCUInfo)
345     if (MCU.Name == MCUName)
346       return std::optional<StringRef>(MCU.Family);
347   return std::nullopt;
348 }
349 
350 std::optional<unsigned> GetMCUSectionAddressData(StringRef MCUName) {
351   for (const auto &MCU : MCUInfo)
352     if (MCU.Name == MCUName && MCU.DataAddr > 0)
353       return std::optional<unsigned>(MCU.DataAddr);
354   return std::nullopt;
355 }
356 
357 const StringRef PossibleAVRLibcLocations[] = {
358     "/avr",
359     "/usr/avr",
360     "/usr/lib/avr",
361 };
362 
363 } // end anonymous namespace
364 
365 /// AVR Toolchain
366 AVRToolChain::AVRToolChain(const Driver &D, const llvm::Triple &Triple,
367                            const ArgList &Args)
368     : Generic_ELF(D, Triple, Args) {
369   GCCInstallation.init(Triple, Args);
370 
371   if (getCPUName(D, Args, Triple).empty())
372     D.Diag(diag::warn_drv_avr_mcu_not_specified);
373 
374   // Only add default libraries if the user hasn't explicitly opted out.
375   if (!Args.hasArg(options::OPT_nostdlib) &&
376       !Args.hasArg(options::OPT_nodefaultlibs) && GCCInstallation.isValid()) {
377     GCCInstallPath = GCCInstallation.getInstallPath();
378     std::string GCCParentPath(GCCInstallation.getParentLibPath());
379     getProgramPaths().push_back(GCCParentPath + "/../bin");
380   }
381 }
382 
383 void AVRToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
384                                              ArgStringList &CC1Args) const {
385   if (DriverArgs.hasArg(options::OPT_nostdinc) ||
386       DriverArgs.hasArg(options::OPT_nostdlibinc))
387     return;
388 
389   // Omit if there is no avr-libc installed.
390   std::optional<std::string> AVRLibcRoot = findAVRLibcInstallation();
391   if (!AVRLibcRoot)
392     return;
393 
394   // Add 'avr-libc/include' to clang system include paths if applicable.
395   std::string AVRInc = *AVRLibcRoot + "/include";
396   if (llvm::sys::fs::is_directory(AVRInc))
397     addSystemInclude(DriverArgs, CC1Args, AVRInc);
398 }
399 
400 void AVRToolChain::addClangTargetOptions(
401     const llvm::opt::ArgList &DriverArgs, llvm::opt::ArgStringList &CC1Args,
402     Action::OffloadKind DeviceOffloadKind) const {
403   // By default, use `.ctors` (not `.init_array`), as required by libgcc, which
404   // runs constructors/destructors on AVR.
405   if (!DriverArgs.hasFlag(options::OPT_fuse_init_array,
406                           options::OPT_fno_use_init_array, false))
407     CC1Args.push_back("-fno-use-init-array");
408   // Use `-fno-use-cxa-atexit` as default, since avr-libc does not support
409   // `__cxa_atexit()`.
410   if (!DriverArgs.hasFlag(options::OPT_fuse_cxa_atexit,
411                           options::OPT_fno_use_cxa_atexit, false))
412     CC1Args.push_back("-fno-use-cxa-atexit");
413 }
414 
415 Tool *AVRToolChain::buildLinker() const {
416   return new tools::AVR::Linker(getTriple(), *this);
417 }
418 
419 std::string
420 AVRToolChain::getCompilerRT(const llvm::opt::ArgList &Args, StringRef Component,
421                             FileType Type = ToolChain::FT_Static) const {
422   assert(Type == ToolChain::FT_Static && "AVR only supports static libraries");
423   // Since AVR can never be a host environment, its compiler-rt library files
424   // should always have ".a" suffix, even on windows.
425   SmallString<32> File("/libclang_rt.");
426   File += Component.str();
427   File += ".a";
428   // Return the default compiler-rt path appended with
429   // "avr/libclang_rt.$COMPONENT.a".
430   SmallString<256> Path(ToolChain::getCompilerRTPath());
431   llvm::sys::path::append(Path, "avr");
432   llvm::sys::path::append(Path, File.str());
433   return std::string(Path.str());
434 }
435 
436 void AVR::Linker::ConstructJob(Compilation &C, const JobAction &JA,
437                                const InputInfo &Output,
438                                const InputInfoList &Inputs, const ArgList &Args,
439                                const char *LinkingOutput) const {
440   const auto &TC = static_cast<const AVRToolChain &>(getToolChain());
441   const Driver &D = getToolChain().getDriver();
442 
443   // Compute information about the target AVR.
444   std::string CPU = getCPUName(D, Args, getToolChain().getTriple());
445   std::optional<StringRef> FamilyName = GetMCUFamilyName(CPU);
446   std::optional<std::string> AVRLibcRoot = TC.findAVRLibcInstallation();
447   std::optional<unsigned> SectionAddressData = GetMCUSectionAddressData(CPU);
448 
449   // Compute the linker program path, and use GNU "avr-ld" as default.
450   const Arg *A = Args.getLastArg(options::OPT_fuse_ld_EQ);
451   std::string Linker = A ? getToolChain().GetLinkerPath(nullptr)
452                          : getToolChain().GetProgramPath(getShortName());
453 
454   ArgStringList CmdArgs;
455 
456   CmdArgs.push_back("-o");
457   CmdArgs.push_back(Output.getFilename());
458 
459   // Enable garbage collection of unused sections.
460   CmdArgs.push_back("--gc-sections");
461 
462   // Add library search paths before we specify libraries.
463   Args.AddAllArgs(CmdArgs, options::OPT_L);
464   getToolChain().AddFilePathLibArgs(Args, CmdArgs);
465 
466   // Currently we only support libgcc and compiler-rt.
467   auto RtLib = TC.GetRuntimeLibType(Args);
468   assert(
469       (RtLib == ToolChain::RLT_Libgcc || RtLib == ToolChain::RLT_CompilerRT) &&
470       "unknown runtime library");
471 
472   // Only add default libraries if the user hasn't explicitly opted out.
473   bool LinkStdlib = false;
474   if (!Args.hasArg(options::OPT_nostdlib) &&
475       !Args.hasArg(options::OPT_nodefaultlibs)) {
476     if (!CPU.empty()) {
477       if (!FamilyName) {
478         // We do not have an entry for this CPU in the family
479         // mapping table yet.
480         D.Diag(diag::warn_drv_avr_family_linking_stdlibs_not_implemented)
481             << CPU;
482       } else if (!AVRLibcRoot) {
483         // No avr-libc found and so no runtime linked.
484         D.Diag(diag::warn_drv_avr_libc_not_found);
485       } else {
486         std::string SubPath = GetMCUSubPath(CPU);
487         // Add path of avr-libc.
488         CmdArgs.push_back(
489             Args.MakeArgString(Twine("-L") + *AVRLibcRoot + "/lib/" + SubPath));
490         if (RtLib == ToolChain::RLT_Libgcc)
491           CmdArgs.push_back(Args.MakeArgString("-L" + TC.getGCCInstallPath() +
492                                                "/" + SubPath));
493         LinkStdlib = true;
494       }
495     }
496     if (!LinkStdlib)
497       D.Diag(diag::warn_drv_avr_stdlib_not_linked);
498   }
499 
500   if (SectionAddressData) {
501     CmdArgs.push_back(
502         Args.MakeArgString("--defsym=__DATA_REGION_ORIGIN__=0x" +
503                            Twine::utohexstr(*SectionAddressData)));
504   } else {
505     // We do not have an entry for this CPU in the address mapping table yet.
506     D.Diag(diag::warn_drv_avr_linker_section_addresses_not_implemented) << CPU;
507   }
508 
509   if (D.isUsingLTO()) {
510     assert(!Inputs.empty() && "Must have at least one input.");
511     addLTOOptions(getToolChain(), Args, CmdArgs, Output, Inputs[0],
512                   D.getLTOMode() == LTOK_Thin);
513   }
514 
515   // If the family name is known, we can link with the device-specific libgcc.
516   // Without it, libgcc will simply not be linked. This matches avr-gcc
517   // behavior.
518   if (LinkStdlib) {
519     assert(!CPU.empty() && "CPU name must be known in order to link stdlibs");
520 
521     CmdArgs.push_back("--start-group");
522 
523     // Add the object file for the CRT.
524     std::string CrtFileName = std::string("-l:crt") + CPU + std::string(".o");
525     CmdArgs.push_back(Args.MakeArgString(CrtFileName));
526 
527     // Link to libgcc.
528     if (RtLib == ToolChain::RLT_Libgcc)
529       CmdArgs.push_back("-lgcc");
530 
531     // Link to generic libraries of avr-libc.
532     CmdArgs.push_back("-lm");
533     CmdArgs.push_back("-lc");
534 
535     // Add the link library specific to the MCU.
536     CmdArgs.push_back(Args.MakeArgString(std::string("-l") + CPU));
537 
538     // Add the relocatable inputs.
539     AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
540 
541     // We directly use libclang_rt.builtins.a as input file, instead of using
542     // '-lclang_rt.builtins'.
543     if (RtLib == ToolChain::RLT_CompilerRT) {
544       std::string RtLib =
545           getToolChain().getCompilerRT(Args, "builtins", ToolChain::FT_Static);
546       if (llvm::sys::fs::exists(RtLib))
547         CmdArgs.push_back(Args.MakeArgString(RtLib));
548     }
549 
550     CmdArgs.push_back("--end-group");
551 
552     // Add user specified linker script.
553     Args.AddAllArgs(CmdArgs, options::OPT_T);
554 
555     if (Args.hasFlag(options::OPT_mrelax, options::OPT_mno_relax, true))
556       CmdArgs.push_back("--relax");
557 
558     // Specify the family name as the emulation mode to use.
559     // This is almost always required because otherwise avr-ld
560     // will assume 'avr2' and warn about the program being larger
561     // than the bare minimum supports.
562     if (Linker.find("avr-ld") != std::string::npos)
563       CmdArgs.push_back(Args.MakeArgString(std::string("-m") + *FamilyName));
564   } else {
565     AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
566   }
567 
568   C.addCommand(std::make_unique<Command>(
569       JA, *this, ResponseFileSupport::AtFileCurCP(), Args.MakeArgString(Linker),
570       CmdArgs, Inputs, Output));
571 }
572 
573 std::optional<std::string> AVRToolChain::findAVRLibcInstallation() const {
574   // Search avr-libc installation according to avr-gcc installation.
575   std::string GCCParent(GCCInstallation.getParentLibPath());
576   std::string Path(GCCParent + "/avr");
577   if (llvm::sys::fs::is_directory(Path))
578     return Path;
579   Path = GCCParent + "/../avr";
580   if (llvm::sys::fs::is_directory(Path))
581     return Path;
582 
583   // Search avr-libc installation from possible locations, and return the first
584   // one that exists, if there is no avr-gcc installed.
585   for (StringRef PossiblePath : PossibleAVRLibcLocations) {
586     std::string Path = getDriver().SysRoot + PossiblePath.str();
587     if (llvm::sys::fs::is_directory(Path))
588       return Path;
589   }
590 
591   return std::nullopt;
592 }
593