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