We need to append-to rather than set CXXFLAGS, otherwise we loose -O2 & -pipe from our defaults. Currently this results in zeromq being built without optimizations at all (or whatever the compiler would default too, essentially always -O0).
Bdb is the same, for the CXX portion of its code. C code has been built with -O2. Boost has actually been unaffected because it receives -O3 from it’s own build flags.
Noticed while reworking #22380. For bdb & zeromq, I assume (haven’t checked) this has been the case since #7165.
You can inspect the effcts in bitcoind comparing a function from a unoptimised library, i.e libzmq.
Build bitcoind with zeromq from depends (7be143a960e2bb9ac81144f55c45731c1bb209c5):
0gmake -C depends NO_QT=1 NO_UPNP=1 NO_NATPMP=1 NO_WALLET=1 -j9
1
2./autogen.sh
3CONFIG_SITE=/path/to/share/config.site ./configure
4gmake -C src bitcoind -j9
Find a zeromq function:
0nm -C src/bitcoind | rg zmq
1...
2000000010053a7e0 T _zmq_ctx_new
Disassemble it:
0lldb src/bitcoind
1disassemble -a 000000010053a7e0
2...
3bitcoind`zmq_ctx_new:
4bitcoind[0x10053a7e0] <+0>: pushq %rbp
5bitcoind[0x10053a7e1] <+1>: movq %rsp, %rbp
6bitcoind[0x10053a7e4] <+4>: subq $0x50, %rsp
7bitcoind[0x10053a7e8] <+8>: callq 0x1004b2ee0 ; zmq::initialize_network()
8bitcoind[0x10053a7ed] <+13>: testb $0x1, %al
9bitcoind[0x10053a7ef] <+15>: jne 0x10053a802 ; <+34>
10bitcoind[0x10053a7f5] <+21>: movq $0x0, -0x8(%rbp)
11bitcoind[0x10053a7fd] <+29>: jmp 0x10053a8e8 ; <+264>
12bitcoind[0x10053a802] <+34>: movq 0xadab7(%rip), %rsi ; (void *)0x0000000000000000
13bitcoind[0x10053a809] <+41>: movl $0x2b8, %edi ; imm = 0x2B8
14bitcoind[0x10053a80e] <+46>: callq 0x100556c58 ; symbol stub for: operator new(unsigned long, std::nothrow_t const&)
15bitcoind[0x10053a813] <+51>: xorl %ecx, %ecx
16bitcoind[0x10053a815] <+53>: movl %ecx, %edx
17bitcoind[0x10053a817] <+55>: movb $0x0, -0x19(%rbp)
18bitcoind[0x10053a81b] <+59>: cmpq $0x0, %rax
19bitcoind[0x10053a81f] <+63>: movq %rax, -0x38(%rbp)
20bitcoind[0x10053a823] <+67>: movq %rdx, -0x40(%rbp)
21bitcoind[0x10053a827] <+71>: je 0x10053a858 ; <+120>
22bitcoind[0x10053a82d] <+77>: movq -0x38(%rbp), %rax
23bitcoind[0x10053a831] <+81>: movq %rax, -0x18(%rbp)
24bitcoind[0x10053a835] <+85>: movb $0x1, -0x19(%rbp)
25bitcoind[0x10053a839] <+89>: movq -0x38(%rbp), %rdi
26bitcoind[0x10053a83d] <+93>: movq %rax, -0x48(%rbp)
27bitcoind[0x10053a841] <+97>: callq 0x100497aa0 ; zmq::ctx_t::ctx_t()
28bitcoind[0x10053a846] <+102>: jmp 0x10053a84b ; <+107>
29bitcoind[0x10053a84b] <+107>: movq -0x48(%rbp), %rax
30bitcoind[0x10053a84f] <+111>: movq %rax, -0x40(%rbp)
31bitcoind[0x10053a853] <+115>: jmp 0x10053a858 ; <+120>
32bitcoind[0x10053a858] <+120>: movq -0x40(%rbp), %rax
33bitcoind[0x10053a85c] <+124>: movq %rax, -0x10(%rbp)
34bitcoind[0x10053a860] <+128>: cmpq $0x0, -0x10(%rbp)
35bitcoind[0x10053a865] <+133>: je 0x10053a8e0 ; <+256>
36bitcoind[0x10053a86b] <+139>: movq -0x10(%rbp), %rdi
37bitcoind[0x10053a86f] <+143>: callq 0x100497ee0 ; zmq::ctx_t::valid() const
38bitcoind[0x10053a874] <+148>: testb $0x1, %al
39bitcoind[0x10053a876] <+150>: jne 0x10053a8db ; <+251>
40bitcoind[0x10053a87c] <+156>: movq -0x10(%rbp), %rax
41bitcoind[0x10053a880] <+160>: cmpq $0x0, %rax
42bitcoind[0x10053a884] <+164>: movq %rax, -0x50(%rbp)
43bitcoind[0x10053a888] <+168>: je 0x10053a8a3 ; <+195>
44bitcoind[0x10053a88e] <+174>: movq -0x50(%rbp), %rdi
45bitcoind[0x10053a892] <+178>: callq 0x100497ec0 ; zmq::ctx_t::~ctx_t()
46bitcoind[0x10053a897] <+183>: movq -0x50(%rbp), %rax
47bitcoind[0x10053a89b] <+187>: movq %rax, %rdi
48bitcoind[0x10053a89e] <+190>: callq 0x100556c3a ; symbol stub for: operator delete(void*)
49bitcoind[0x10053a8a3] <+195>: movq $0x0, -0x8(%rbp)
50bitcoind[0x10053a8ab] <+203>: jmp 0x10053a8e8 ; <+264>
51bitcoind[0x10053a8b0] <+208>: movq %rax, -0x28(%rbp)
52bitcoind[0x10053a8b4] <+212>: movl %edx, -0x2c(%rbp)
53bitcoind[0x10053a8b7] <+215>: testb $0x1, -0x19(%rbp)
54bitcoind[0x10053a8bb] <+219>: jne 0x10053a8c6 ; <+230>
55bitcoind[0x10053a8c1] <+225>: jmp 0x10053a8d6 ; <+246>
56bitcoind[0x10053a8c6] <+230>: movq 0xad9f3(%rip), %rsi ; (void *)0x0000000000000000
57bitcoind[0x10053a8cd] <+237>: movq -0x18(%rbp), %rdi
58bitcoind[0x10053a8d1] <+241>: callq 0x100556c40 ; symbol stub for: operator delete(void*, std::nothrow_t const&)
59bitcoind[0x10053a8d6] <+246>: jmp 0x10053a8f2 ; <+274>
60bitcoind[0x10053a8db] <+251>: jmp 0x10053a8e0 ; <+256>
61bitcoind[0x10053a8e0] <+256>: movq -0x10(%rbp), %rax
62bitcoind[0x10053a8e4] <+260>: movq %rax, -0x8(%rbp)
63bitcoind[0x10053a8e8] <+264>: movq -0x8(%rbp), %rax
64bitcoind[0x10053a8ec] <+268>: addq $0x50, %rsp
65bitcoind[0x10053a8f0] <+272>: popq %rbp
66bitcoind[0x10053a8f1] <+273>: retq
67bitcoind[0x10053a8f2] <+274>: movq -0x28(%rbp), %rdi
68bitcoind[0x10053a8f6] <+278>: callq 0x100556856 ; symbol stub for: _Unwind_Resume
69bitcoind[0x10053a8fb] <+283>: ud2
70bitcoind[0x10053a8fd] <+285>: nopl (%rax)
Cleanup and repeat after changing the zeromq cxxflags to be $(package)_cxxflags+=-std=c++17:
0gmake clean
1gmake -C depends NO_QT=1 NO_UPNP=1 NO_NATPMP=1 NO_WALLET=1 -j9
2gmake -C src bitcoind -j9
3
4nm -C src/bitcoind | rg zmq
5...
600000001004d5170 T _zmq_ctx_new
Disassemble the same function which has now been built with -O2:
0lldb src/bitcoind
1disassemble -a 00000001004d5170
2...
3bitcoind`zmq_ctx_new:
4bitcoind[0x1004d5170] <+0>: pushq %rbp
5bitcoind[0x1004d5171] <+1>: movq %rsp, %rbp
6bitcoind[0x1004d5174] <+4>: pushq %r14
7bitcoind[0x1004d5176] <+6>: pushq %rbx
8bitcoind[0x1004d5177] <+7>: callq 0x10049cbc0 ; zmq::initialize_network()
9bitcoind[0x1004d517c] <+12>: testb %al, %al
10bitcoind[0x1004d517e] <+14>: je 0x1004d51bd ; <+77>
11bitcoind[0x1004d5180] <+16>: movq 0xab139(%rip), %rsi ; (void *)0x0000000000000000
12bitcoind[0x1004d5187] <+23>: movl $0x2b8, %edi ; imm = 0x2B8
13bitcoind[0x1004d518c] <+28>: callq 0x1004f0e5a ; symbol stub for: operator new(unsigned long, std::nothrow_t const&)
14bitcoind[0x1004d5191] <+33>: testq %rax, %rax
15bitcoind[0x1004d5194] <+36>: je 0x1004d51bd ; <+77>
16bitcoind[0x1004d5196] <+38>: movq %rax, %rbx
17bitcoind[0x1004d5199] <+41>: movq %rax, %rdi
18bitcoind[0x1004d519c] <+44>: callq 0x100493400 ; zmq::ctx_t::ctx_t()
19bitcoind[0x1004d51a1] <+49>: movq %rbx, %rdi
20bitcoind[0x1004d51a4] <+52>: callq 0x1004936e0 ; zmq::ctx_t::valid() const
21bitcoind[0x1004d51a9] <+57>: testb %al, %al
22bitcoind[0x1004d51ab] <+59>: jne 0x1004d51bf ; <+79>
23bitcoind[0x1004d51ad] <+61>: movq %rbx, %rdi
24bitcoind[0x1004d51b0] <+64>: callq 0x1004936d0 ; zmq::ctx_t::~ctx_t()
25bitcoind[0x1004d51b5] <+69>: movq %rbx, %rdi
26bitcoind[0x1004d51b8] <+72>: callq 0x1004f0e42 ; symbol stub for: operator delete(void*)
27bitcoind[0x1004d51bd] <+77>: xorl %ebx, %ebx
28bitcoind[0x1004d51bf] <+79>: movq %rbx, %rax
29bitcoind[0x1004d51c2] <+82>: popq %rbx
30bitcoind[0x1004d51c3] <+83>: popq %r14
31bitcoind[0x1004d51c5] <+85>: popq %rbp
32bitcoind[0x1004d51c6] <+86>: retq
33bitcoind[0x1004d51c7] <+87>: movq %rax, %r14
34bitcoind[0x1004d51ca] <+90>: movq 0xab0ef(%rip), %rsi ; (void *)0x0000000000000000
35bitcoind[0x1004d51d1] <+97>: movq %rbx, %rdi
36bitcoind[0x1004d51d4] <+100>: callq 0x1004f0e48 ; symbol stub for: operator delete(void*, std::nothrow_t const&)
37bitcoind[0x1004d51d9] <+105>: movq %r14, %rdi
38bitcoind[0x1004d51dc] <+108>: callq 0x1004f0a6a ; symbol stub for: _Unwind_Resume
39bitcoind[0x1004d51e1] <+113>: ud2
40bitcoind[0x1004d51e3] <+115>: nopw %cs:(%rax,%rax)
41bitcoind[0x1004d51ed] <+125>: nopl (%rax)
