when gdb bitcoind program, gdb prints message "can't open to read symbols"

[lovecodelc]

Hi all, this is my first time to ask question on GitHub, I come from China. Maybe there are some mistakes in this question, Sorry.

Before I write C++ on Linux, such Ubuntu, Now turn to on Max OS.

I install Bitcoin Core code and compile it successful according to https://github.com/bitcoin/bitcoin/blob/master/doc/build-osx.md , and start it successful.

But when I gdb bitcoind binary executable, i meet some problems, such as:

1. Reading symbols from /***/bitcoin/src/bitcoind...
   warning: can't find symbol '_Z10ParseHexUVRK8UniValueRKNSt3__112basic_stringIcNS2_11char_traitsIcEENS2_9allocatorIcEEEE' in minsymtab. why?

2. warning: `/private/tmp/boost-20160924-23596- 1q34jy8/boost_1_61_0/bin.v2/libs/chrono/build/darwin-4.2.1/release/threading-multi/process_cpu_clocks.o': can't open to read symbols: No such file or directory. why?

//a lot of "can't open to read symbols: No such file or directory" about boost

3)when i gdb funcation by step, it notices "", even if i modify Makefile(in ./src/Makefile, not ./Makefile)configuration, before "CXXFLAGS = -g -O2", now "
CXXFLAGS = -g -O0", it seems not work, why?

4. when I use gdb breakpoint, such HTTPReq_JSONRPC funcation, when request arrives, the break is stop other place not HTTPReq_JSONRPC, why?

How can i solve above questions??
Thank you.

[laanwj]

when I use gdb breakpoint, such HTTPReq_JSONRPC funcation, when request arrives, the break is stop other place not HTTPReq_JSONRPC, why?

That's what you get if you use gdb with an optimized executable. The association between line numbers and addresses will be partially muddled.

The easiest way to get a debuggable executable is to configure with --enable-debug. This will automatically set the optimization flags so that gdb can make sense of the executable and includes full symbols.

[lovecodelc]

@laanwj Thank you, I execute "make clean" and "./configure --enable-debug", then "make";
but it appears same problem when debug it:

(gdb) b HTTPReq_JSONRPC
Breakpoint 1 at 0x10165829b: HTTPReq_JSONRPC. (2 locations) //why 2 locations???
(gdb) info b
Num Type Disp Enb Address What
1 breakpoint keep y
1.1 y 0x000000010165829b in SerReadWrite<CSizeComputer, std::__1::vector<CTxOut, std::__1::allocator > >(CSizeComputer&, std::__1::vector<CTxOut, std::__1::allocator > const&, int, int, CSerActionSerialize) at ./serialize.h:919
1.2 y 0x00000001016582b0 in std::__1::vector<CTxInWitness, std::__1::allocator >::resize(unsigned long)
at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/vector:1994

[laanwj]

In that case your debugger and/or compiler is probably broken. I can't help you with that.

[jonasschnelli]

Maybe try lldb which is the native debugger since Xcode4.8 or so.
Maybe do a git clean -dxf(danger: deletes all unstated files) and configure (with --enable-debug) and compile again?

[laanwj]

Closing this as it isn't really issue, more of a Q/A