Мобильная версияИнициализация большой карты в заголовке приводит к сбою g++ ⇐ C++
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Anonymous
Инициализация большой карты в заголовке приводит к сбою g++
I am trying to make a simple tool that requires some lookup on a fixed key-value dataset, so I try to lazily throw all data to a hashmap in the header file:
/** main.h */ #include #include using namespace std; const unordered_map test = { {0xDEADC0DE, "Some short text less than 50 characters"}, // 46K rows of data }; I haven't implemented anything yet, but just including this header file is enough to crash the compiler.
main.cpp
/** main.cpp */ #include #include "main.h" int main() { return 0; } After maxing out a CPU core for 5 minutes, the g++ (cc1plus) eats up all 32GB of RAM and crashes. I know a large header could impact compiling performance but I did not expect it to exhaust resources and fail. How does it use up 32GB RAM when the size of the header file is only 1.9 MB? Could someone please help explain the problem in my case?
The version I am using is g++ (GCC) 13.2.1 20230801, with the command /usr/bin/g++ -O3 -DNDEBUG -o CMakeFiles/main.cpp.o -c /home/foo/main.cpp
Update
I also did some experiments with different sizes of map:
Element Number Build Time 10 00:00:01.043 100 00:00:01.187 1000 00:00:05.225 2000 00:00:10.200 5000 00:00:25.604 10000 00:00:52.208 20000 00:01:48.090 Update
The problem is solved by disabling compiler optimization. I am using the VS Code CMake extension and the Release profile adds -O3 to the g++ argument. Removing this allows the project (46K rows) to be compiled in 6 seconds. The compiler must be trying hard to cast some optimization magic that unfortunately goes wrong.
Источник: https://stackoverflow.com/questions/780 ... -g-crashes
I am trying to make a simple tool that requires some lookup on a fixed key-value dataset, so I try to lazily throw all data to a hashmap in the header file:
/** main.h */ #include #include using namespace std; const unordered_map test = { {0xDEADC0DE, "Some short text less than 50 characters"}, // 46K rows of data }; I haven't implemented anything yet, but just including this header file is enough to crash the compiler.
main.cpp
/** main.cpp */ #include #include "main.h" int main() { return 0; } After maxing out a CPU core for 5 minutes, the g++ (cc1plus) eats up all 32GB of RAM and crashes. I know a large header could impact compiling performance but I did not expect it to exhaust resources and fail. How does it use up 32GB RAM when the size of the header file is only 1.9 MB? Could someone please help explain the problem in my case?
The version I am using is g++ (GCC) 13.2.1 20230801, with the command /usr/bin/g++ -O3 -DNDEBUG -o CMakeFiles/main.cpp.o -c /home/foo/main.cpp
Update
I also did some experiments with different sizes of map:
Element Number Build Time 10 00:00:01.043 100 00:00:01.187 1000 00:00:05.225 2000 00:00:10.200 5000 00:00:25.604 10000 00:00:52.208 20000 00:01:48.090 Update
The problem is solved by disabling compiler optimization. I am using the VS Code CMake extension and the Release profile adds -O3 to the g++ argument. Removing this allows the project (46K rows) to be compiled in 6 seconds. The compiler must be trying hard to cast some optimization magic that unfortunately goes wrong.
Источник: https://stackoverflow.com/questions/780 ... -g-crashes
