Notes:Exceptions and C++
From Maths
Contents
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Here I tell the compiler that some functions exist, and make it compile (with -O3) a function that uses them. We compare the results when we disable exception handling, and when we enable it.
Code
#include <string> #include <vector> template<class T> class DeleteWhenDone; namespace std { template<class T> void swap(DeleteWhenDone<T>&,DeleteWhenDone<T>&) noexcept; } template<class T> class DeleteWhenDone { public: DeleteWhenDone() { data = nullptr; } DeleteWhenDone(T* source): data(source) { } DeleteWhenDone(const DeleteWhenDone&) = delete; DeleteWhenDone(DeleteWhenDone&& from) noexcept: data(from.data) { from.data = nullptr; } DeleteWhenDone& operator=(const DeleteWhenDone&) = delete; DeleteWhenDone& operator=(DeleteWhenDone&& from) { DeleteWhenDone tmp(::std::forward<DeleteWhenDone>(from)); ::std::swap(*this,tmp); return *this; } ~DeleteWhenDone() { if(data != nullptr) { delete data; } } T& operator*() const { return *data; } private: T* data; friend void ::std::swap<>(DeleteWhenDone&,DeleteWhenDone&) noexcept; }; namespace std { template<class T> void swap(::DeleteWhenDone<T>& A, ::DeleteWhenDone<T>& B) noexcept { T* tmp = A.data; A.data = B.data; B.data = tmp; } } class Task { public: virtual void doTask() =0; virtual ~Task() { } }; /* These functions are NOT noexcept so they may throw - the compiler knows nothing about them*/ /* see http://stackoverflow.com/questions/18543980/symbol-not-found-when-using-template-defined-in-a-library/18544093#18544093 for example*/ void DoSomeTask(Task&); ::std::string IMayAlsoThrow(int group); ::std::vector<DeleteWhenDone<Task>> HiThereIMayThrow(int group); int notMain(int argc, const char** args) { ::std::vector<::std::string> someStuff = { "Hi there", "Hello" }; someStuff.push_back(IMayAlsoThrow(argc)); ::std::vector<DeleteWhenDone<Task>> tasks(HiThereIMayThrow(argc+1)); int count = 0; for(auto& thing : tasks) { count++; DoSomeTask(*thing); } return count; }
Result
Just -O3 (~310 instructions)
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With -fno-exceptions (~200 instructions)
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0000000000000000 <notMain(int, char const**)>: 0: 41 56 push %r14 2: be 00 00 00 00 mov $0x0,%esi 7: 41 55 push %r13 9: 41 89 fd mov %edi,%r13d c: 41 54 push %r12 e: 55 push %rbp f: 53 push %rbx 10: 48 83 ec 60 sub $0x60,%rsp 14: 48 8d 54 24 0e lea 0xe(%rsp),%rdx 19: 48 8d 7c 24 40 lea 0x40(%rsp),%rdi 1e: e8 00 00 00 00 callq 23 <notMain(int, char const**)+0x23> 23: 48 8d 7c 24 48 lea 0x48(%rsp),%rdi 28: 48 8d 54 24 0f lea 0xf(%rsp),%rdx 2d: be 00 00 00 00 mov $0x0,%esi 32: e8 00 00 00 00 callq 37 <notMain(int, char const**)+0x37> 37: bf 10 00 00 00 mov $0x10,%edi 3c: 48 c7 44 24 20 00 00 movq $0x0,0x20(%rsp) 43: 00 00 45: 48 c7 44 24 28 00 00 movq $0x0,0x28(%rsp) 4c: 00 00 4e: 48 c7 44 24 30 00 00 movq $0x0,0x30(%rsp) 55: 00 00 57: e8 00 00 00 00 callq 5c <notMain(int, char const**)+0x5c> 5c: 48 8d 6c 24 40 lea 0x40(%rsp),%rbp 61: 49 89 c6 mov %rax,%r14 64: 48 89 44 24 20 mov %rax,0x20(%rsp) 69: 48 8d 40 10 lea 0x10(%rax),%rax 6d: 4c 89 f3 mov %r14,%rbx 70: 4c 8d 65 10 lea 0x10(%rbp),%r12 74: 48 89 44 24 30 mov %rax,0x30(%rsp) 79: 0f 1f 80 00 00 00 00 nopl 0x0(%rax) 80: 48 85 db test %rbx,%rbx 83: 74 0b je 90 <notMain(int, char const**)+0x90> 85: 48 89 ee mov %rbp,%rsi 88: 48 89 df mov %rbx,%rdi 8b: e8 00 00 00 00 callq 90 <notMain(int, char const**)+0x90> 90: 48 83 c5 08 add $0x8,%rbp 94: 48 83 c3 08 add $0x8,%rbx 98: 4c 39 e5 cmp %r12,%rbp 9b: 75 e3 jne 80 <notMain(int, char const**)+0x80> 9d: 48 8b 44 24 48 mov 0x48(%rsp),%rax a2: 48 89 5c 24 28 mov %rbx,0x28(%rsp) a7: 48 8d 78 e8 lea -0x18(%rax),%rdi ab: 48 81 ff 00 00 00 00 cmp $0x0,%rdi b2: 0f 85 7d 01 00 00 jne 235 <notMain(int, char const**)+0x235> b8: 4c 8d 64 24 10 lea 0x10(%rsp),%r12 bd: 48 8b 44 24 40 mov 0x40(%rsp),%rax c2: 48 8d 78 e8 lea -0x18(%rax),%rdi c6: 48 81 ff 00 00 00 00 cmp $0x0,%rdi cd: 0f 85 cf 02 00 00 jne 3a2 <notMain(int, char const**)+0x3a2> d3: 44 89 ee mov %r13d,%esi d6: 4c 89 e7 mov %r12,%rdi d9: e8 00 00 00 00 callq de <notMain(int, char const**)+0xde> de: 48 8b 44 24 28 mov 0x28(%rsp),%rax e3: 48 3b 44 24 30 cmp 0x30(%rsp),%rax e8: 0f 84 0e 01 00 00 je 1fc <notMain(int, char const**)+0x1fc> ee: 48 85 c0 test %rax,%rax f1: 48 8b 54 24 10 mov 0x10(%rsp),%rdx f6: 74 11 je 109 <notMain(int, char const**)+0x109> f8: 48 89 10 mov %rdx,(%rax) fb: 48 c7 44 24 10 00 00 movq $0x0,0x10(%rsp) 102: 00 00 104: ba 00 00 00 00 mov $0x0,%edx 109: 48 83 c0 08 add $0x8,%rax 10d: 48 89 44 24 28 mov %rax,0x28(%rsp) 112: 48 8d 7a e8 lea -0x18(%rdx),%rdi 116: 48 81 ff 00 00 00 00 cmp $0x0,%rdi 11d: 0f 85 ab 02 00 00 jne 3ce <notMain(int, char const**)+0x3ce> 123: 41 8d 75 01 lea 0x1(%r13),%esi 127: 48 8d 7c 24 40 lea 0x40(%rsp),%rdi 12c: e8 00 00 00 00 callq 131 <notMain(int, char const**)+0x131> 131: 48 8b 5c 24 40 mov 0x40(%rsp),%rbx 136: 4c 8b 6c 24 48 mov 0x48(%rsp),%r13 13b: 4c 39 eb cmp %r13,%rbx 13e: 0f 84 cf 00 00 00 je 213 <notMain(int, char const**)+0x213> 144: 31 ed xor %ebp,%ebp 146: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 14d: 00 00 00 150: 48 8b 3b mov (%rbx),%rdi 153: 83 c5 01 add $0x1,%ebp 156: e8 00 00 00 00 callq 15b <notMain(int, char const**)+0x15b> 15b: 48 83 c3 08 add $0x8,%rbx 15f: 49 39 dd cmp %rbx,%r13 162: 75 ec jne 150 <notMain(int, char const**)+0x150> 164: 4c 8b 6c 24 48 mov 0x48(%rsp),%r13 169: 48 8b 5c 24 40 mov 0x40(%rsp),%rbx 16e: 49 39 dd cmp %rbx,%r13 171: 74 21 je 194 <notMain(int, char const**)+0x194> 173: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 178: 48 8b 3b mov (%rbx),%rdi 17b: 48 85 ff test %rdi,%rdi 17e: 74 06 je 186 <notMain(int, char const**)+0x186> 180: 48 8b 17 mov (%rdi),%rdx 183: ff 52 10 callq *0x10(%rdx) 186: 48 83 c3 08 add $0x8,%rbx 18a: 49 39 dd cmp %rbx,%r13 18d: 75 e9 jne 178 <notMain(int, char const**)+0x178> 18f: 4c 8b 6c 24 40 mov 0x40(%rsp),%r13 194: 4d 85 ed test %r13,%r13 197: 74 08 je 1a1 <notMain(int, char const**)+0x1a1> 199: 4c 89 ef mov %r13,%rdi 19c: e8 00 00 00 00 callq 1a1 <notMain(int, char const**)+0x1a1> 1a1: 4c 8b 6c 24 28 mov 0x28(%rsp),%r13 1a6: 48 8b 5c 24 20 mov 0x20(%rsp),%rbx 1ab: 49 39 dd cmp %rbx,%r13 1ae: 74 47 je 1f7 <notMain(int, char const**)+0x1f7> 1b0: b8 00 00 00 00 mov $0x0,%eax 1b5: 48 85 c0 test %rax,%rax 1b8: 0f 84 58 02 00 00 je 416 <notMain(int, char const**)+0x416> 1be: 66 90 xchg %ax,%ax 1c0: 48 8b 03 mov (%rbx),%rax 1c3: 48 8d 78 e8 lea -0x18(%rax),%rdi 1c7: 48 81 ff 00 00 00 00 cmp $0x0,%rdi 1ce: 75 4d jne 21d <notMain(int, char const**)+0x21d> 1d0: 48 83 c3 08 add $0x8,%rbx 1d4: 49 39 dd cmp %rbx,%r13 1d7: 75 e7 jne 1c0 <notMain(int, char const**)+0x1c0> 1d9: 48 8b 7c 24 20 mov 0x20(%rsp),%rdi 1de: 48 85 ff test %rdi,%rdi 1e1: 74 05 je 1e8 <notMain(int, char const**)+0x1e8> 1e3: e8 00 00 00 00 callq 1e8 <notMain(int, char const**)+0x1e8> 1e8: 48 83 c4 60 add $0x60,%rsp 1ec: 89 e8 mov %ebp,%eax 1ee: 5b pop %rbx 1ef: 5d pop %rbp 1f0: 41 5c pop %r12 1f2: 41 5d pop %r13 1f4: 41 5e pop %r14 1f6: c3 retq 1f7: 4c 89 ef mov %r13,%rdi 1fa: eb e2 jmp 1de <notMain(int, char const**)+0x1de> 1fc: 48 8d 7c 24 20 lea 0x20(%rsp),%rdi 201: 4c 89 e6 mov %r12,%rsi 204: e8 00 00 00 00 callq 209 <notMain(int, char const**)+0x209> 209: 48 8b 54 24 10 mov 0x10(%rsp),%rdx 20e: e9 ff fe ff ff jmpq 112 <notMain(int, char const**)+0x112> 213: 49 89 dd mov %rbx,%r13 216: 31 ed xor %ebp,%ebp 218: e9 77 ff ff ff jmpq 194 <notMain(int, char const**)+0x194> 21d: ba ff ff ff ff mov $0xffffffff,%edx 222: f0 0f c1 50 f8 lock xadd %edx,-0x8(%rax) 227: 85 d2 test %edx,%edx 229: 7f a5 jg 1d0 <notMain(int, char const**)+0x1d0> 22b: 4c 89 e6 mov %r12,%rsi 22e: e8 00 00 00 00 callq 233 <notMain(int, char const**)+0x233> 233: eb 9b jmp 1d0 <notMain(int, char const**)+0x1d0> 235: b9 00 00 00 00 mov $0x0,%ecx 23a: 48 8d 57 10 lea 0x10(%rdi),%rdx 23e: 48 85 c9 test %rcx,%rcx 241: 0f 84 ed 01 00 00 je 434 <notMain(int, char const**)+0x434> 247: b8 ff ff ff ff mov $0xffffffff,%eax 24c: f0 0f c1 02 lock xadd %eax,(%rdx) 250: 85 c0 test %eax,%eax 252: 4c 8d 64 24 10 lea 0x10(%rsp),%r12 257: 0f 8f 60 fe ff ff jg bd <notMain(int, char const**)+0xbd> 25d: 4c 89 e6 mov %r12,%rsi 260: e8 00 00 00 00 callq 265 <notMain(int, char const**)+0x265> 265: e9 53 fe ff ff jmpq bd <notMain(int, char const**)+0xbd> 26a: 49 89 c4 mov %rax,%r12 26d: 48 8b 44 24 10 mov 0x10(%rsp),%rax 272: 48 8d 74 24 40 lea 0x40(%rsp),%rsi 277: 48 8d 78 e8 lea -0x18(%rax),%rdi 27b: e8 00 00 00 00 callq 280 <notMain(int, char const**)+0x280> 280: 48 8b 6c 24 28 mov 0x28(%rsp),%rbp 285: 48 8b 5c 24 20 mov 0x20(%rsp),%rbx 28a: 48 39 dd cmp %rbx,%rbp 28d: 0f 84 07 02 00 00 je 49a <notMain(int, char const**)+0x49a> 293: b8 00 00 00 00 mov $0x0,%eax 298: 48 85 c0 test %rax,%rax 29b: 0f 84 db 01 00 00 je 47c <notMain(int, char const**)+0x47c> 2a1: 48 8b 13 mov (%rbx),%rdx 2a4: 48 8d 7a e8 lea -0x18(%rdx),%rdi 2a8: 48 81 ff 00 00 00 00 cmp $0x0,%rdi 2af: 0f 85 a6 01 00 00 jne 45b <notMain(int, char const**)+0x45b> 2b5: 48 83 c3 08 add $0x8,%rbx 2b9: 48 39 dd cmp %rbx,%rbp 2bc: 75 e3 jne 2a1 <notMain(int, char const**)+0x2a1> 2be: 48 8b 7c 24 20 mov 0x20(%rsp),%rdi 2c3: 48 85 ff test %rdi,%rdi 2c6: 74 05 je 2cd <notMain(int, char const**)+0x2cd> 2c8: e8 00 00 00 00 callq 2cd <notMain(int, char const**)+0x2cd> 2cd: 4c 89 e7 mov %r12,%rdi 2d0: e8 00 00 00 00 callq 2d5 <notMain(int, char const**)+0x2d5> 2d5: 48 89 c7 mov %rax,%rdi 2d8: 4c 8d 64 24 10 lea 0x10(%rsp),%r12 2dd: e8 00 00 00 00 callq 2e2 <notMain(int, char const**)+0x2e2> 2e2: 4c 39 f3 cmp %r14,%rbx 2e5: 74 18 je 2ff <notMain(int, char const**)+0x2ff> 2e7: 49 8b 06 mov (%r14),%rax 2ea: 4c 89 e6 mov %r12,%rsi 2ed: 49 83 c6 08 add $0x8,%r14 2f1: 48 8d 78 e8 lea -0x18(%rax),%rdi 2f5: e8 00 00 00 00 callq 2fa <notMain(int, char const**)+0x2fa> 2fa: 4c 39 f3 cmp %r14,%rbx 2fd: 75 e8 jne 2e7 <notMain(int, char const**)+0x2e7> 2ff: e8 00 00 00 00 callq 304 <notMain(int, char const**)+0x304> 304: 4c 8d 64 24 10 lea 0x10(%rsp),%r12 309: 48 89 c3 mov %rax,%rbx 30c: 48 8b 7c 24 20 mov 0x20(%rsp),%rdi 311: 48 85 ff test %rdi,%rdi 314: 74 05 je 31b <notMain(int, char const**)+0x31b> 316: e8 00 00 00 00 callq 31b <notMain(int, char const**)+0x31b> 31b: 48 8b 44 24 48 mov 0x48(%rsp),%rax 320: 4c 89 e6 mov %r12,%rsi 323: 48 8d 78 e8 lea -0x18(%rax),%rdi 327: e8 00 00 00 00 callq 32c <notMain(int, char const**)+0x32c> 32c: 48 8b 44 24 40 mov 0x40(%rsp),%rax 331: 4c 89 e6 mov %r12,%rsi 334: 48 8d 78 e8 lea -0x18(%rax),%rdi 338: e8 00 00 00 00 callq 33d <notMain(int, char const**)+0x33d> 33d: 48 89 df mov %rbx,%rdi 340: e8 00 00 00 00 callq 345 <notMain(int, char const**)+0x345> 345: 48 8b 6c 24 48 mov 0x48(%rsp),%rbp 34a: 48 8b 5c 24 40 mov 0x40(%rsp),%rbx 34f: 49 89 c4 mov %rax,%r12 352: 48 39 dd cmp %rbx,%rbp 355: 74 1e je 375 <notMain(int, char const**)+0x375> 357: 48 8b 3b mov (%rbx),%rdi 35a: 48 85 ff test %rdi,%rdi 35d: 74 06 je 365 <notMain(int, char const**)+0x365> 35f: 48 8b 07 mov (%rdi),%rax 362: ff 50 10 callq *0x10(%rax) 365: 48 83 c3 08 add $0x8,%rbx 369: 48 39 dd cmp %rbx,%rbp 36c: 75 e9 jne 357 <notMain(int, char const**)+0x357> 36e: 48 8b 7c 24 40 mov 0x40(%rsp),%rdi 373: eb 03 jmp 378 <notMain(int, char const**)+0x378> 375: 48 89 ef mov %rbp,%rdi 378: 48 85 ff test %rdi,%rdi 37b: 0f 84 ff fe ff ff je 280 <notMain(int, char const**)+0x280> 381: e8 00 00 00 00 callq 386 <notMain(int, char const**)+0x386> 386: e9 f5 fe ff ff jmpq 280 <notMain(int, char const**)+0x280> 38b: 49 89 c4 mov %rax,%r12 38e: 66 90 xchg %ax,%ax 390: e9 eb fe ff ff jmpq 280 <notMain(int, char const**)+0x280> 395: 48 89 c3 mov %rax,%rbx 398: e8 00 00 00 00 callq 39d <notMain(int, char const**)+0x39d> 39d: e9 6a ff ff ff jmpq 30c <notMain(int, char const**)+0x30c> 3a2: b9 00 00 00 00 mov $0x0,%ecx 3a7: 48 8d 57 10 lea 0x10(%rdi),%rdx 3ab: 48 85 c9 test %rcx,%rcx 3ae: 74 4e je 3fe <notMain(int, char const**)+0x3fe> 3b0: b8 ff ff ff ff mov $0xffffffff,%eax 3b5: f0 0f c1 02 lock xadd %eax,(%rdx) 3b9: 85 c0 test %eax,%eax 3bb: 0f 8f 12 fd ff ff jg d3 <notMain(int, char const**)+0xd3> 3c1: 4c 89 e6 mov %r12,%rsi 3c4: e8 00 00 00 00 callq 3c9 <notMain(int, char const**)+0x3c9> 3c9: e9 05 fd ff ff jmpq d3 <notMain(int, char const**)+0xd3> 3ce: b9 00 00 00 00 mov $0x0,%ecx 3d3: 48 8d 47 10 lea 0x10(%rdi),%rax 3d7: 48 85 c9 test %rcx,%rcx 3da: 74 2f je 40b <notMain(int, char const**)+0x40b> 3dc: ba ff ff ff ff mov $0xffffffff,%edx 3e1: f0 0f c1 10 lock xadd %edx,(%rax) 3e5: 89 d0 mov %edx,%eax 3e7: 85 c0 test %eax,%eax 3e9: 0f 8f 34 fd ff ff jg 123 <notMain(int, char const**)+0x123> 3ef: 48 8d 74 24 40 lea 0x40(%rsp),%rsi 3f4: e8 00 00 00 00 callq 3f9 <notMain(int, char const**)+0x3f9> 3f9: e9 25 fd ff ff jmpq 123 <notMain(int, char const**)+0x123> 3fe: 8b 50 f8 mov -0x8(%rax),%edx 401: 8d 4a ff lea -0x1(%rdx),%ecx 404: 89 48 f8 mov %ecx,-0x8(%rax) 407: 89 d0 mov %edx,%eax 409: eb ae jmp 3b9 <notMain(int, char const**)+0x3b9> 40b: 8b 42 f8 mov -0x8(%rdx),%eax 40e: 8d 48 ff lea -0x1(%rax),%ecx 411: 89 4a f8 mov %ecx,-0x8(%rdx) 414: eb d1 jmp 3e7 <notMain(int, char const**)+0x3e7> 416: 48 8b 03 mov (%rbx),%rax 419: 48 8d 78 e8 lea -0x18(%rax),%rdi 41d: 48 81 ff 00 00 00 00 cmp $0x0,%rdi 424: 75 1e jne 444 <notMain(int, char const**)+0x444> 426: 48 83 c3 08 add $0x8,%rbx 42a: 49 39 dd cmp %rbx,%r13 42d: 75 e7 jne 416 <notMain(int, char const**)+0x416> 42f: e9 a5 fd ff ff jmpq 1d9 <notMain(int, char const**)+0x1d9> 434: 8b 50 f8 mov -0x8(%rax),%edx 437: 8d 4a ff lea -0x1(%rdx),%ecx 43a: 89 48 f8 mov %ecx,-0x8(%rax) 43d: 89 d0 mov %edx,%eax 43f: e9 0c fe ff ff jmpq 250 <notMain(int, char const**)+0x250> 444: 8b 50 f8 mov -0x8(%rax),%edx 447: 8d 4a ff lea -0x1(%rdx),%ecx 44a: 85 d2 test %edx,%edx 44c: 89 48 f8 mov %ecx,-0x8(%rax) 44f: 7f d5 jg 426 <notMain(int, char const**)+0x426> 451: 4c 89 e6 mov %r12,%rsi 454: e8 00 00 00 00 callq 459 <notMain(int, char const**)+0x459> 459: eb cb jmp 426 <notMain(int, char const**)+0x426> 45b: b8 ff ff ff ff mov $0xffffffff,%eax 460: f0 0f c1 42 f8 lock xadd %eax,-0x8(%rdx) 465: 85 c0 test %eax,%eax 467: 0f 8f 48 fe ff ff jg 2b5 <notMain(int, char const**)+0x2b5> 46d: 48 8d 74 24 0f lea 0xf(%rsp),%rsi 472: e8 00 00 00 00 callq 477 <notMain(int, char const**)+0x477> 477: e9 39 fe ff ff jmpq 2b5 <notMain(int, char const**)+0x2b5> 47c: 48 8b 03 mov (%rbx),%rax 47f: 48 8d 78 e8 lea -0x18(%rax),%rdi 483: 48 81 ff 00 00 00 00 cmp $0x0,%rdi 48a: 75 16 jne 4a2 <notMain(int, char const**)+0x4a2> 48c: 48 83 c3 08 add $0x8,%rbx 490: 48 39 dd cmp %rbx,%rbp 493: 75 e7 jne 47c <notMain(int, char const**)+0x47c> 495: e9 24 fe ff ff jmpq 2be <notMain(int, char const**)+0x2be> 49a: 48 89 ef mov %rbp,%rdi 49d: e9 21 fe ff ff jmpq 2c3 <notMain(int, char const**)+0x2c3> 4a2: 8b 50 f8 mov -0x8(%rax),%edx 4a5: 8d 4a ff lea -0x1(%rdx),%ecx 4a8: 85 d2 test %edx,%edx 4aa: 89 48 f8 mov %ecx,-0x8(%rax) 4ad: 7f dd jg 48c <notMain(int, char const**)+0x48c> 4af: 48 8d 74 24 0f lea 0xf(%rsp),%rsi 4b4: e8 00 00 00 00 callq 4b9 <notMain(int, char const**)+0x4b9> 4b9: eb d1 jmp 48c <notMain(int, char const**)+0x48c> |
0000000000000000 <notMain(int, char const**)>: 0: 41 55 push %r13 2: 41 89 fd mov %edi,%r13d 5: be 00 00 00 00 mov $0x0,%esi a: 41 54 push %r12 c: 55 push %rbp d: 53 push %rbx e: 48 83 ec 58 sub $0x58,%rsp 12: 48 8d 54 24 0d lea 0xd(%rsp),%rdx 17: 48 8d 7c 24 30 lea 0x30(%rsp),%rdi 1c: 48 8d 6c 24 30 lea 0x30(%rsp),%rbp 21: e8 00 00 00 00 callq 26 <notMain(int, char const**)+0x26> 26: 48 8d 7c 24 38 lea 0x38(%rsp),%rdi 2b: 48 8d 54 24 0e lea 0xe(%rsp),%rdx 30: be 00 00 00 00 mov $0x0,%esi 35: 4c 8d 65 10 lea 0x10(%rbp),%r12 39: e8 00 00 00 00 callq 3e <notMain(int, char const**)+0x3e> 3e: bf 10 00 00 00 mov $0x10,%edi 43: 48 c7 44 24 10 00 00 movq $0x0,0x10(%rsp) 4a: 00 00 4c: 48 c7 44 24 18 00 00 movq $0x0,0x18(%rsp) 53: 00 00 55: 48 c7 44 24 20 00 00 movq $0x0,0x20(%rsp) 5c: 00 00 5e: e8 00 00 00 00 callq 63 <notMain(int, char const**)+0x63> 63: 48 89 c3 mov %rax,%rbx 66: 48 89 44 24 10 mov %rax,0x10(%rsp) 6b: 48 8d 40 10 lea 0x10(%rax),%rax 6f: 48 89 44 24 20 mov %rax,0x20(%rsp) 74: 0f 1f 40 00 nopl 0x0(%rax) 78: 48 85 db test %rbx,%rbx 7b: 74 0b je 88 <notMain(int, char const**)+0x88> 7d: 48 89 ee mov %rbp,%rsi 80: 48 89 df mov %rbx,%rdi 83: e8 00 00 00 00 callq 88 <notMain(int, char const**)+0x88> 88: 48 83 c5 08 add $0x8,%rbp 8c: 48 83 c3 08 add $0x8,%rbx 90: 4c 39 e5 cmp %r12,%rbp 93: 75 e3 jne 78 <notMain(int, char const**)+0x78> 95: 48 8b 44 24 38 mov 0x38(%rsp),%rax 9a: 48 89 5c 24 18 mov %rbx,0x18(%rsp) 9f: 48 8d 78 e8 lea -0x18(%rax),%rdi a3: 48 81 ff 00 00 00 00 cmp $0x0,%rdi aa: 0f 85 74 01 00 00 jne 224 <notMain(int, char const**)+0x224> b0: 48 8b 44 24 30 mov 0x30(%rsp),%rax b5: 48 8d 78 e8 lea -0x18(%rax),%rdi b9: 48 81 ff 00 00 00 00 cmp $0x0,%rdi c0: 0f 85 92 01 00 00 jne 258 <notMain(int, char const**)+0x258> c6: 48 8d 7c 24 30 lea 0x30(%rsp),%rdi cb: 44 89 ee mov %r13d,%esi ce: e8 00 00 00 00 callq d3 <notMain(int, char const**)+0xd3> d3: 48 8b 44 24 18 mov 0x18(%rsp),%rax d8: 48 3b 44 24 20 cmp 0x20(%rsp),%rax dd: 0f 84 0e 01 00 00 je 1f1 <notMain(int, char const**)+0x1f1> e3: 48 85 c0 test %rax,%rax e6: 48 8b 54 24 30 mov 0x30(%rsp),%rdx eb: 74 11 je fe <notMain(int, char const**)+0xfe> ed: 48 89 10 mov %rdx,(%rax) f0: 48 c7 44 24 30 00 00 movq $0x0,0x30(%rsp) f7: 00 00 f9: ba 00 00 00 00 mov $0x0,%edx fe: 48 83 c0 08 add $0x8,%rax 102: 48 89 44 24 18 mov %rax,0x18(%rsp) 107: 48 8d 7a e8 lea -0x18(%rdx),%rdi 10b: 48 81 ff 00 00 00 00 cmp $0x0,%rdi 112: 0f 85 88 01 00 00 jne 2a0 <notMain(int, char const**)+0x2a0> 118: 41 8d 75 01 lea 0x1(%r13),%esi 11c: 48 8d 7c 24 30 lea 0x30(%rsp),%rdi 121: e8 00 00 00 00 callq 126 <notMain(int, char const**)+0x126> 126: 48 8b 5c 24 30 mov 0x30(%rsp),%rbx 12b: 4c 8b 6c 24 38 mov 0x38(%rsp),%r13 130: 4c 39 eb cmp %r13,%rbx 133: 0f 84 ac 00 00 00 je 1e5 <notMain(int, char const**)+0x1e5> 139: 31 ed xor %ebp,%ebp 13b: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 140: 48 8b 3b mov (%rbx),%rdi 143: 48 83 c3 08 add $0x8,%rbx 147: 83 c5 01 add $0x1,%ebp 14a: e8 00 00 00 00 callq 14f <notMain(int, char const**)+0x14f> 14f: 49 39 dd cmp %rbx,%r13 152: 75 ec jne 140 <notMain(int, char const**)+0x140> 154: 4c 8b 64 24 38 mov 0x38(%rsp),%r12 159: 48 8b 5c 24 30 mov 0x30(%rsp),%rbx 15e: 49 39 dc cmp %rbx,%r12 161: 74 21 je 184 <notMain(int, char const**)+0x184> 163: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 168: 48 8b 3b mov (%rbx),%rdi 16b: 48 85 ff test %rdi,%rdi 16e: 74 06 je 176 <notMain(int, char const**)+0x176> 170: 48 8b 07 mov (%rdi),%rax 173: ff 50 10 callq *0x10(%rax) 176: 48 83 c3 08 add $0x8,%rbx 17a: 49 39 dc cmp %rbx,%r12 17d: 75 e9 jne 168 <notMain(int, char const**)+0x168> 17f: 4c 8b 64 24 30 mov 0x30(%rsp),%r12 184: 4d 85 e4 test %r12,%r12 187: 74 08 je 191 <notMain(int, char const**)+0x191> 189: 4c 89 e7 mov %r12,%rdi 18c: e8 00 00 00 00 callq 191 <notMain(int, char const**)+0x191> 191: 4c 8b 64 24 18 mov 0x18(%rsp),%r12 196: 48 8b 5c 24 10 mov 0x10(%rsp),%rbx 19b: 49 39 dc cmp %rbx,%r12 19e: 74 4c je 1ec <notMain(int, char const**)+0x1ec> 1a0: b8 00 00 00 00 mov $0x0,%eax 1a5: 48 85 c0 test %rax,%rax 1a8: 0f 84 22 01 00 00 je 2d0 <notMain(int, char const**)+0x2d0> 1ae: 66 90 xchg %ax,%ax 1b0: 48 8b 03 mov (%rbx),%rax 1b3: 48 8d 78 e8 lea -0x18(%rax),%rdi 1b7: 48 81 ff 00 00 00 00 cmp $0x0,%rdi 1be: 75 4a jne 20a <notMain(int, char const**)+0x20a> 1c0: 48 83 c3 08 add $0x8,%rbx 1c4: 49 39 dc cmp %rbx,%r12 1c7: 75 e7 jne 1b0 <notMain(int, char const**)+0x1b0> 1c9: 48 8b 7c 24 10 mov 0x10(%rsp),%rdi 1ce: 48 85 ff test %rdi,%rdi 1d1: 74 05 je 1d8 <notMain(int, char const**)+0x1d8> 1d3: e8 00 00 00 00 callq 1d8 <notMain(int, char const**)+0x1d8> 1d8: 48 83 c4 58 add $0x58,%rsp 1dc: 89 e8 mov %ebp,%eax 1de: 5b pop %rbx 1df: 5d pop %rbp 1e0: 41 5c pop %r12 1e2: 41 5d pop %r13 1e4: c3 retq 1e5: 49 89 dc mov %rbx,%r12 1e8: 31 ed xor %ebp,%ebp 1ea: eb 98 jmp 184 <notMain(int, char const**)+0x184> 1ec: 4c 89 e7 mov %r12,%rdi 1ef: eb dd jmp 1ce <notMain(int, char const**)+0x1ce> 1f1: 48 8d 74 24 30 lea 0x30(%rsp),%rsi 1f6: 48 8d 7c 24 10 lea 0x10(%rsp),%rdi 1fb: e8 00 00 00 00 callq 200 <notMain(int, char const**)+0x200> 200: 48 8b 54 24 30 mov 0x30(%rsp),%rdx 205: e9 fd fe ff ff jmpq 107 <notMain(int, char const**)+0x107> 20a: ba ff ff ff ff mov $0xffffffff,%edx 20f: f0 0f c1 50 f8 lock xadd %edx,-0x8(%rax) 214: 85 d2 test %edx,%edx 216: 7f a8 jg 1c0 <notMain(int, char const**)+0x1c0> 218: 48 8d 74 24 0f lea 0xf(%rsp),%rsi 21d: e8 00 00 00 00 callq 222 <notMain(int, char const**)+0x222> 222: eb 9c jmp 1c0 <notMain(int, char const**)+0x1c0> 224: b9 00 00 00 00 mov $0x0,%ecx 229: 48 8d 57 10 lea 0x10(%rdi),%rdx 22d: 48 85 c9 test %rcx,%rcx 230: 74 54 je 286 <notMain(int, char const**)+0x286> 232: b8 ff ff ff ff mov $0xffffffff,%eax 237: f0 0f c1 02 lock xadd %eax,(%rdx) 23b: 85 c0 test %eax,%eax 23d: 0f 8f 6d fe ff ff jg b0 <notMain(int, char const**)+0xb0> 243: 48 8d 74 24 0f lea 0xf(%rsp),%rsi 248: e8 00 00 00 00 callq 24d <notMain(int, char const**)+0x24d> 24d: e9 5e fe ff ff jmpq b0 <notMain(int, char const**)+0xb0> 252: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) 258: b9 00 00 00 00 mov $0x0,%ecx 25d: 48 8d 57 10 lea 0x10(%rdi),%rdx 261: 48 85 c9 test %rcx,%rcx 264: 74 2d je 293 <notMain(int, char const**)+0x293> 266: b8 ff ff ff ff mov $0xffffffff,%eax 26b: f0 0f c1 02 lock xadd %eax,(%rdx) 26f: 85 c0 test %eax,%eax 271: 0f 8f 4f fe ff ff jg c6 <notMain(int, char const**)+0xc6> 277: 48 8d 74 24 0f lea 0xf(%rsp),%rsi 27c: e8 00 00 00 00 callq 281 <notMain(int, char const**)+0x281> 281: e9 40 fe ff ff jmpq c6 <notMain(int, char const**)+0xc6> 286: 8b 50 f8 mov -0x8(%rax),%edx 289: 8d 4a ff lea -0x1(%rdx),%ecx 28c: 89 48 f8 mov %ecx,-0x8(%rax) 28f: 89 d0 mov %edx,%eax 291: eb a8 jmp 23b <notMain(int, char const**)+0x23b> 293: 8b 50 f8 mov -0x8(%rax),%edx 296: 8d 4a ff lea -0x1(%rdx),%ecx 299: 89 48 f8 mov %ecx,-0x8(%rax) 29c: 89 d0 mov %edx,%eax 29e: eb cf jmp 26f <notMain(int, char const**)+0x26f> 2a0: b9 00 00 00 00 mov $0x0,%ecx 2a5: 48 8d 47 10 lea 0x10(%rdi),%rax 2a9: 48 85 c9 test %rcx,%rcx 2ac: 74 40 je 2ee <notMain(int, char const**)+0x2ee> 2ae: ba ff ff ff ff mov $0xffffffff,%edx 2b3: f0 0f c1 10 lock xadd %edx,(%rax) 2b7: 89 d0 mov %edx,%eax 2b9: 85 c0 test %eax,%eax 2bb: 0f 8f 57 fe ff ff jg 118 <notMain(int, char const**)+0x118> 2c1: 48 8d 74 24 0f lea 0xf(%rsp),%rsi 2c6: e8 00 00 00 00 callq 2cb <notMain(int, char const**)+0x2cb> 2cb: e9 48 fe ff ff jmpq 118 <notMain(int, char const**)+0x118> 2d0: 48 8b 03 mov (%rbx),%rax 2d3: 48 8d 78 e8 lea -0x18(%rax),%rdi 2d7: 48 81 ff 00 00 00 00 cmp $0x0,%rdi 2de: 75 19 jne 2f9 <notMain(int, char const**)+0x2f9> 2e0: 48 83 c3 08 add $0x8,%rbx 2e4: 49 39 dc cmp %rbx,%r12 2e7: 75 e7 jne 2d0 <notMain(int, char const**)+0x2d0> 2e9: e9 db fe ff ff jmpq 1c9 <notMain(int, char const**)+0x1c9> 2ee: 8b 42 f8 mov -0x8(%rdx),%eax 2f1: 8d 48 ff lea -0x1(%rax),%ecx 2f4: 89 4a f8 mov %ecx,-0x8(%rdx) 2f7: eb c0 jmp 2b9 <notMain(int, char const**)+0x2b9> 2f9: 8b 50 f8 mov -0x8(%rax),%edx 2fc: 8d 4a ff lea -0x1(%rdx),%ecx 2ff: 85 d2 test %edx,%edx 301: 89 48 f8 mov %ecx,-0x8(%rax) 304: 7f da jg 2e0 <notMain(int, char const**)+0x2e0> 306: 48 8d 74 24 0f lea 0xf(%rsp),%rsi 30b: e8 00 00 00 00 callq 310 <notMain(int, char const**)+0x310> 310: eb ce jmp 2e0 <notMain(int, char const**)+0x2e0> |
Why?
Take the following:
AR someFunction(A1 a1, A2 a2, A3 a3, ..., AN an) {
L1 l1;someCallThatMayThrow();
L2 l2;someOtherCall();
}
Suppose line 3 throws, then we must destroy l1 but l2 doesn't exist yet! Suppose line 5 throws instead, then we must destroy both l1 and l2 THEN "unwind the stack" to go to the next caller and destruct its locals correctly until the exception is handled.
This is a lot of work! Evidently.
C++ was able to see the vector push_back and other methods here (and thus inline them) but because it knows nothing about the 3 function prototypes given it must suppose they can do anything, and generate safe code.
