Test ffi008 fails with "multiple definition of `mystruct'"

[bavier]

Steps to Reproduce

$ guix time-machine --commit=a62f0f6d85ca1c16674e6fcf284c5aca08986603 -- build idris@1.3.3

This uses gcc 10.3.0 and binutils 2.37

Expected Behavior

Test should pass.

Observed Behavior

The following error message:

    ffi008:
Error: test/ffi008
ld: /tmp/guix-build-idris-1.3.3.drv-0/ccmIt9AI.o:(.bss.mystruct+0x0): multiple definition of `mystruct'; /tmp/guix-build-idris-1.3.3.drv-0/cc3UDCaU.o:(.bss.mystruct+0x0): first defined here
collect2: error: ld returned 1 exit status
run.sh: line 3: ./ffi008: No such file or directory

FAIL (8.87s)
      --- test/ffi008/output    2022-04-13 04:43:20.294548527 +0000
      +++ test/ffi008/expected.out      1970-01-01 00:00:01.000000000 +0000
      @@ -1 +1,5 @@
      -FAILURE: "gcc" ["-fwrapv","-fno-strict-overflow","-std=c99","-pipe","-fdata-sections","-ffunction-sections","-D_POSIX_C_SOURCE=200809L","-DHAS_PTHREAD","-DIDRIS_ENABLE_STATS","-I.","-Wl,-gc-sections","/tmp/guix-build-idris-1.3.3.drv-0/idris2352-0.c","-L/gnu/store/a6181fb8957g7ayrgmqxgys4lcy7gxqf-idris-1.3.3/lib/idris/rts","-lidris_rts","-lgmp","-DIDRIS_GMP","-lpthread","-I/gnu/store/a6181fb8957g7ayrgmqxgys4lcy7gxqf-idris-1.3.3/lib/idris/rts","-lm","-I.","-I/gnu/store/a6181fb8957g7ayrgmqxgys4lcy7gxqf-idris-1.3.3/lib/idris/libs/contrib","-I../base","-I../prelude","-I.","-I/gnu/store/a6181fb8957g7ayrgmqxgys4lcy7gxqf-idris-1.3.3/lib/idris/libs/prelude","-I/gnu/store/a6181fb8957g7ayrgmqxgys4lcy7gxqf-idris-1.3.3/lib/idris/libs/base","ffi008.c","-o","ffi008"]
      +True
      +True
      +a: 122 b: 0
      +4
      +00000010
      \ No newline at end of file

      Use -p '/ffi008/' to rerun this test only.

Suggested fix

Currently the mystruct structure becomes defined in both the linked ffi008.o and the generated idris code, via the %include C "ffi008.h". The structure should be defined in the .c and only declared in .h. The following patch fixes the test for me:

--- a/test/ffi008/ffi008.h      1969-12-31 18:00:01.000000000 -0600                                                                                                                                                                                                             
+++ a/test/ffi008/ffi008.h      2022-04-13 00:32:35.561262598 -0500                                                                                                                                                                                                             
@@ -10,7 +10,7 @@                                                                                                                                                                                                                                                               
     int16_t b;                                                                                                                                                                                                                                                                 
 };                                                                                                                                                                                                                                                                             
                                                                                                                                                                                                                                                                                
-struct test2 mystruct;                                                                                                                                                                                                                                                         
+extern struct test2 mystruct;                                                                                                                                                                                                                                                  
                                                                                                                                                                                                                                                                                
 int size1(void);                                                                                                                                                                                                                                                               
 int size2(void);                                                                                                                                                                                                                                                               
--- a/test/ffi008/ffi008.c      1969-12-31 18:00:01.000000000 -0600                                                                                                                                                                                                             
+++ a/test/ffi008/ffi008.c      2022-04-13 00:32:53.145186302 -0500                                                                                                                                                                                                             
@@ -11,6 +11,8 @@                                                                                                                                                                                                                                                               
     return sizeof(struct test2);                                                                                                                                                                                                                                               
 }                                                                                                                                                                                                                                                                              
                                                                                                                                                                                                                                                                                
+struct test2 mystruct;                                                                                                                                                                                                                                                         
+                                                                                                                                                                                                                                                                               
 void print_mystruct(void) {                                                                                                                                                                                                                                                    
     printf("a: %d b: %d\n", mystruct.a, mystruct.b);                                                                                                                                                                                                                           
 }