[RISC-V] Shoudn't linker GC get rid of the unused section?

[futog]

lib.h:
    void throw_with_try_catch();
    void fun();
 
 lib.cpp:
    void undefined();
 
    void throw_with_try_catch() {
       try {
          throw 1;
       } catch(int) {}
 
       undefined();
    }
 
    void fun() {}

lib.o: compiled with -ffunction-sections -fdata-sections

    main.cpp:
       #include "lib.h"
    
       int main() {
          fun();
       }

clang main.cpp -o main lib.o -Wl,--gc-sections -mno-relax:
ld.lld: error: undefined symbol: undefined()

Is this the expected behavior?

[quic-seaswara]

I assume this is because the linker keeps the sections matching

(__gxx_personality_v0) and *(.gcc_except_table)

The default GNU linker script used by the GNU linker does not have a KEEP for these sections.

Can the linker not assume these implicit assumptions ?

[futog]

Resolved by #140692.

[llvmbot]

@llvm/issue-subscribers-backend-risc-v

Author: Gergely Futo (futog)

``` lib.h: void throw_with_try_catch(); void fun();

lib.cpp:
   void undefined();

   void throw_with_try_catch() {
      try {
         throw 1;
      } catch(int) {}

      undefined();
   }

   void fun() {}

    
lib.o: compiled with `-ffunction-sections -fdata-sections`
    

main.cpp:
   #include "lib.h"

   int main() {
      fun();
   }

clang main.cpp -o main lib.o -Wl,--gc-sections -mno-relax:
**`ld.lld: error: undefined symbol: undefined()`**

Is this the expected behavior?
</details>

[llvmbot]

@llvm/issue-subscribers-llvm-mc

Author: Gergely Futo (futog)

``` lib.h: void throw_with_try_catch(); void fun();

lib.cpp:
   void undefined();

   void throw_with_try_catch() {
      try {
         throw 1;
      } catch(int) {}

      undefined();
   }

   void fun() {}

    
lib.o: compiled with `-ffunction-sections -fdata-sections`
    

main.cpp:
   #include "lib.h"

   int main() {
      fun();
   }

clang main.cpp -o main lib.o -Wl,--gc-sections -mno-relax:
**`ld.lld: error: undefined symbol: undefined()`**

Is this the expected behavior?
</details>