1Compiler-RT
2================================
3
4This directory and its subdirectories contain source code for the compiler
5support routines.
6
7Compiler-RT is open source software. You may freely distribute it under the
8terms of the license agreement found in LICENSE.txt.
9
10================================
11
12This is a replacement library for libgcc. Each function is contained
13in its own file. Each function has a corresponding unit test under
14test/Unit.
15
16A rudimentary script to test each file is in the file called
17test/Unit/test.
18
19Here is the specification for this library:
20
21http://gcc.gnu.org/onlinedocs/gccint/Libgcc.html#Libgcc
22
23Here is a synopsis of the contents of this library:
24
25typedef int si_int;
26typedef unsigned su_int;
27
28typedef long long di_int;
29typedef unsigned long long du_int;
30
31// Integral bit manipulation
32
33di_int __ashldi3(di_int a, si_int b); // a << b
34ti_int __ashlti3(ti_int a, si_int b); // a << b
35
36di_int __ashrdi3(di_int a, si_int b); // a >> b arithmetic (sign fill)
37ti_int __ashrti3(ti_int a, si_int b); // a >> b arithmetic (sign fill)
38di_int __lshrdi3(di_int a, si_int b); // a >> b logical (zero fill)
39ti_int __lshrti3(ti_int a, si_int b); // a >> b logical (zero fill)
40
41si_int __clzsi2(si_int a); // count leading zeros
42si_int __clzdi2(di_int a); // count leading zeros
43si_int __clzti2(ti_int a); // count leading zeros
44si_int __ctzsi2(si_int a); // count trailing zeros
45si_int __ctzdi2(di_int a); // count trailing zeros
46si_int __ctzti2(ti_int a); // count trailing zeros
47
48si_int __ffssi2(si_int a); // find least significant 1 bit
49si_int __ffsdi2(di_int a); // find least significant 1 bit
50si_int __ffsti2(ti_int a); // find least significant 1 bit
51
52si_int __paritysi2(si_int a); // bit parity
53si_int __paritydi2(di_int a); // bit parity
54si_int __parityti2(ti_int a); // bit parity
55
56si_int __popcountsi2(si_int a); // bit population
57si_int __popcountdi2(di_int a); // bit population
58si_int __popcountti2(ti_int a); // bit population
59
60uint32_t __bswapsi2(uint32_t a); // a byteswapped
61uint64_t __bswapdi2(uint64_t a); // a byteswapped
62
63// Integral arithmetic
64
65di_int __negdi2 (di_int a); // -a
66ti_int __negti2 (ti_int a); // -a
67di_int __muldi3 (di_int a, di_int b); // a * b
68ti_int __multi3 (ti_int a, ti_int b); // a * b
69si_int __divsi3 (si_int a, si_int b); // a / b signed
70di_int __divdi3 (di_int a, di_int b); // a / b signed
71ti_int __divti3 (ti_int a, ti_int b); // a / b signed
72su_int __udivsi3 (su_int n, su_int d); // a / b unsigned
73du_int __udivdi3 (du_int a, du_int b); // a / b unsigned
74tu_int __udivti3 (tu_int a, tu_int b); // a / b unsigned
75si_int __modsi3 (si_int a, si_int b); // a % b signed
76di_int __moddi3 (di_int a, di_int b); // a % b signed
77ti_int __modti3 (ti_int a, ti_int b); // a % b signed
78su_int __umodsi3 (su_int a, su_int b); // a % b unsigned
79du_int __umoddi3 (du_int a, du_int b); // a % b unsigned
80tu_int __umodti3 (tu_int a, tu_int b); // a % b unsigned
81du_int __udivmoddi4(du_int a, du_int b, du_int* rem); // a / b, *rem = a % b unsigned
82tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem); // a / b, *rem = a % b unsigned
83su_int __udivmodsi4(su_int a, su_int b, su_int* rem); // a / b, *rem = a % b unsigned
84si_int __divmodsi4(si_int a, si_int b, si_int* rem); // a / b, *rem = a % b signed
85
86
87
88// Integral arithmetic with trapping overflow
89
90si_int __absvsi2(si_int a); // abs(a)
91di_int __absvdi2(di_int a); // abs(a)
92ti_int __absvti2(ti_int a); // abs(a)
93
94si_int __negvsi2(si_int a); // -a
95di_int __negvdi2(di_int a); // -a
96ti_int __negvti2(ti_int a); // -a
97
98si_int __addvsi3(si_int a, si_int b); // a + b
99di_int __addvdi3(di_int a, di_int b); // a + b
100ti_int __addvti3(ti_int a, ti_int b); // a + b
101
102si_int __subvsi3(si_int a, si_int b); // a - b
103di_int __subvdi3(di_int a, di_int b); // a - b
104ti_int __subvti3(ti_int a, ti_int b); // a - b
105
106si_int __mulvsi3(si_int a, si_int b); // a * b
107di_int __mulvdi3(di_int a, di_int b); // a * b
108ti_int __mulvti3(ti_int a, ti_int b); // a * b
109
110
111// Integral arithmetic which returns if overflow
112
113si_int __mulosi4(si_int a, si_int b, int* overflow); // a * b, overflow set to one if result not in signed range
114di_int __mulodi4(di_int a, di_int b, int* overflow); // a * b, overflow set to one if result not in signed range
115ti_int __muloti4(ti_int a, ti_int b, int* overflow); // a * b, overflow set to
116 one if result not in signed range
117
118
119// Integral comparison: a < b -> 0
120// a == b -> 1
121// a > b -> 2
122
123si_int __cmpdi2 (di_int a, di_int b);
124si_int __cmpti2 (ti_int a, ti_int b);
125si_int __ucmpdi2(du_int a, du_int b);
126si_int __ucmpti2(tu_int a, tu_int b);
127
128// Integral / floating point conversion
129
130di_int __fixsfdi( float a);
131di_int __fixdfdi( double a);
132di_int __fixxfdi(long double a);
133
134ti_int __fixsfti( float a);
135ti_int __fixdfti( double a);
136ti_int __fixxfti(long double a);
137uint64_t __fixtfdi(long double input); // ppc only, doesn't match documentation
138
139su_int __fixunssfsi( float a);
140su_int __fixunsdfsi( double a);
141su_int __fixunsxfsi(long double a);
142
143du_int __fixunssfdi( float a);
144du_int __fixunsdfdi( double a);
145du_int __fixunsxfdi(long double a);
146
147tu_int __fixunssfti( float a);
148tu_int __fixunsdfti( double a);
149tu_int __fixunsxfti(long double a);
150uint64_t __fixunstfdi(long double input); // ppc only
151
152float __floatdisf(di_int a);
153double __floatdidf(di_int a);
154long double __floatdixf(di_int a);
155long double __floatditf(int64_t a); // ppc only
156
157float __floattisf(ti_int a);
158double __floattidf(ti_int a);
159long double __floattixf(ti_int a);
160
161float __floatundisf(du_int a);
162double __floatundidf(du_int a);
163long double __floatundixf(du_int a);
164long double __floatunditf(uint64_t a); // ppc only
165
166float __floatuntisf(tu_int a);
167double __floatuntidf(tu_int a);
168long double __floatuntixf(tu_int a);
169
170// Floating point raised to integer power
171
172float __powisf2( float a, si_int b); // a ^ b
173double __powidf2( double a, si_int b); // a ^ b
174long double __powixf2(long double a, si_int b); // a ^ b
175long double __powitf2(long double a, si_int b); // ppc only, a ^ b
176
177// Complex arithmetic
178
179// (a + ib) * (c + id)
180
181 float _Complex __mulsc3( float a, float b, float c, float d);
182 double _Complex __muldc3(double a, double b, double c, double d);
183long double _Complex __mulxc3(long double a, long double b,
184 long double c, long double d);
185long double _Complex __multc3(long double a, long double b,
186 long double c, long double d); // ppc only
187
188// (a + ib) / (c + id)
189
190 float _Complex __divsc3( float a, float b, float c, float d);
191 double _Complex __divdc3(double a, double b, double c, double d);
192long double _Complex __divxc3(long double a, long double b,
193 long double c, long double d);
194long double _Complex __divtc3(long double a, long double b,
195 long double c, long double d); // ppc only
196
197
198// Runtime support
199
200// __clear_cache() is used to tell process that new instructions have been
201// written to an address range. Necessary on processors that do not have
202// a unified instruction and data cache.
203void __clear_cache(void* start, void* end);
204
205// __enable_execute_stack() is used with nested functions when a trampoline
206// function is written onto the stack and that page range needs to be made
207// executable.
208void __enable_execute_stack(void* addr);
209
210// __gcc_personality_v0() is normally only called by the system unwinder.
211// C code (as opposed to C++) normally does not need a personality function
212// because there are no catch clauses or destructors to be run. But there
213// is a C language extension __attribute__((cleanup(func))) which marks local
214// variables as needing the cleanup function "func" to be run when the
215// variable goes out of scope. That includes when an exception is thrown,
216// so a personality handler is needed.
217_Unwind_Reason_Code __gcc_personality_v0(int version, _Unwind_Action actions,
218 uint64_t exceptionClass, struct _Unwind_Exception* exceptionObject,
219 _Unwind_Context_t context);
220
221// for use with some implementations of assert() in <assert.h>
222void __eprintf(const char* format, const char* assertion_expression,
223 const char* line, const char* file);
224
225// for systems with emulated thread local storage
226void* __emutls_get_address(struct __emutls_control*);
227
228
229// Power PC specific functions
230
231// There is no C interface to the saveFP/restFP functions. They are helper
232// functions called by the prolog and epilog of functions that need to save
233// a number of non-volatile float point registers.
234saveFP
235restFP
236
237// PowerPC has a standard template for trampoline functions. This function
238// generates a custom trampoline function with the specific realFunc
239// and localsPtr values.
240void __trampoline_setup(uint32_t* trampOnStack, int trampSizeAllocated,
241 const void* realFunc, void* localsPtr);
242
243// adds two 128-bit double-double precision values ( x + y )
244long double __gcc_qadd(long double x, long double y);
245
246// subtracts two 128-bit double-double precision values ( x - y )
247long double __gcc_qsub(long double x, long double y);
248
249// multiples two 128-bit double-double precision values ( x * y )
250long double __gcc_qmul(long double x, long double y);
251
252// divides two 128-bit double-double precision values ( x / y )
253long double __gcc_qdiv(long double a, long double b);
254
255
256// ARM specific functions
257
258// There is no C interface to the switch* functions. These helper functions
259// are only needed by Thumb1 code for efficient switch table generation.
260switch16
261switch32
262switch8
263switchu8
264
265// There is no C interface to the *_vfp_d8_d15_regs functions. There are
266// called in the prolog and epilog of Thumb1 functions. When the C++ ABI use
267// SJLJ for exceptions, each function with a catch clause or destuctors needs
268// to save and restore all registers in it prolog and epliog. But there is
269// no way to access vector and high float registers from thumb1 code, so the
270// compiler must add call outs to these helper functions in the prolog and
271// epilog.
272restore_vfp_d8_d15_regs
273save_vfp_d8_d15_regs
274
275
276// Note: long ago ARM processors did not have floating point hardware support.
277// Floating point was done in software and floating point parameters were
278// passed in integer registers. When hardware support was added for floating
279// point, new *vfp functions were added to do the same operations but with
280// floating point parameters in floating point registers.
281
282// Undocumented functions
283
284float __addsf3vfp(float a, float b); // Appears to return a + b
285double __adddf3vfp(double a, double b); // Appears to return a + b
286float __divsf3vfp(float a, float b); // Appears to return a / b
287double __divdf3vfp(double a, double b); // Appears to return a / b
288int __eqsf2vfp(float a, float b); // Appears to return one
289 // iff a == b and neither is NaN.
290int __eqdf2vfp(double a, double b); // Appears to return one
291 // iff a == b and neither is NaN.
292double __extendsfdf2vfp(float a); // Appears to convert from
293 // float to double.
294int __fixdfsivfp(double a); // Appears to convert from
295 // double to int.
296int __fixsfsivfp(float a); // Appears to convert from
297 // float to int.
298unsigned int __fixunssfsivfp(float a); // Appears to convert from
299 // float to unsigned int.
300unsigned int __fixunsdfsivfp(double a); // Appears to convert from
301 // double to unsigned int.
302double __floatsidfvfp(int a); // Appears to convert from
303 // int to double.
304float __floatsisfvfp(int a); // Appears to convert from
305 // int to float.
306double __floatunssidfvfp(unsigned int a); // Appears to convert from
307 // unisgned int to double.
308float __floatunssisfvfp(unsigned int a); // Appears to convert from
309 // unisgned int to float.
310int __gedf2vfp(double a, double b); // Appears to return __gedf2
311 // (a >= b)
312int __gesf2vfp(float a, float b); // Appears to return __gesf2
313 // (a >= b)
314int __gtdf2vfp(double a, double b); // Appears to return __gtdf2
315 // (a > b)
316int __gtsf2vfp(float a, float b); // Appears to return __gtsf2
317 // (a > b)
318int __ledf2vfp(double a, double b); // Appears to return __ledf2
319 // (a <= b)
320int __lesf2vfp(float a, float b); // Appears to return __lesf2
321 // (a <= b)
322int __ltdf2vfp(double a, double b); // Appears to return __ltdf2
323 // (a < b)
324int __ltsf2vfp(float a, float b); // Appears to return __ltsf2
325 // (a < b)
326double __muldf3vfp(double a, double b); // Appears to return a * b
327float __mulsf3vfp(float a, float b); // Appears to return a * b
328int __nedf2vfp(double a, double b); // Appears to return __nedf2
329 // (a != b)
330double __negdf2vfp(double a); // Appears to return -a
331float __negsf2vfp(float a); // Appears to return -a
332float __negsf2vfp(float a); // Appears to return -a
333double __subdf3vfp(double a, double b); // Appears to return a - b
334float __subsf3vfp(float a, float b); // Appears to return a - b
335float __truncdfsf2vfp(double a); // Appears to convert from
336 // double to float.
337int __unorddf2vfp(double a, double b); // Appears to return __unorddf2
338int __unordsf2vfp(float a, float b); // Appears to return __unordsf2
339
340
341Preconditions are listed for each function at the definition when there are any.
342Any preconditions reflect the specification at
343http://gcc.gnu.org/onlinedocs/gccint/Libgcc.html#Libgcc.
344
345Assumptions are listed in "int_lib.h", and in individual files. Where possible
346assumptions are checked at compile time.
347