···

       
1411
       
1411
       
 
       
### Compiler and Linker wrapper hooks {#compiler-linker-wrapper-hooks}

     

       
1412
       
1412
       
 
       


     

       
1413
       
1413
       
 
       
If the file `${cc}/nix-support/cc-wrapper-hook` exists, it will be run at the end of the [compiler wrapper](#cc-wrapper).

     

       
1414
       
1414
       
+
       
If the file `${binutils}/nix-support/ld-wrapper-hook` exists, it will be run at the end of the linker wrapper, before the linker runs.

     

       
1414
       
1415
       
 
       
If the file `${binutils}/nix-support/post-link-hook` exists, it will be run at the end of the linker wrapper.

     

       
1415
       
1416
       
 
       
These hooks allow a user to inject code into the wrappers.

     

       
1416
       
1417
       
 
       
As an example, these hooks can be used to extract `extraBefore`, `params` and `extraAfter` which store all the command line arguments passed to the compiler and linker respectively.

     

···

       
237
       
237
       
 
       
    extraAfter+=(--build-id="${NIX_BUILD_ID_STYLE:-sha1}")

     

       
238
       
238
       
 
       
fi

     

       
239
       
239
       
 
       


     

       
240
       
240
       
+
       
# if a ld-wrapper-hook exists, run it.

     

       
241
       
241
       
+
       
if [[ -e @out@/nix-support/ld-wrapper-hook ]]; then

     

       
242
       
242
       
+
       
    linker=@prog@

     

       
243
       
243
       
+
       
    source @out@/nix-support/ld-wrapper-hook

     

       
244
       
244
       
+
       
fi

     

       
240
       
245
       
 
       


     

       
241
       
246
       
 
       
# Optionally print debug info.

     

       
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247
       
 
       
if (( "${NIX_DEBUG:-0}" >= 1 )); then

     

···

       
232
       
232
       
 
       
    extraAfter+=(-- "${positionalArgs[@]}")

     

       
233
       
233
       
 
       
fi

     

       
234
       
234
       
 
       


     

       
235
       
235
       
+
       
# if a cc-wrapper-hook exists, run it.

     

       
236
       
236
       
+
       
if [[ -e @out@/nix-support/cc-wrapper-hook ]]; then

     

       
237
       
237
       
+
       
    compiler=@prog@

     

       
238
       
238
       
+
       
    source @out@/nix-support/cc-wrapper-hook

     

       
239
       
239
       
+
       
fi

     

       
240
       
240
       
+
       


     

       
235
       
241
       
 
       
# Optionally print debug info.

     

       
236
       
242
       
 
       
if (( "${NIX_DEBUG:-0}" >= 1 )); then

     

       
237
       
243
       
 
       
    # Old bash workaround, see ld-wrapper for explanation.

     
···

       
245
       
251
       
 
       


     

       
246
       
252
       
 
       
PATH="$path_backup"

     

       
247
       
253
       
 
       
# Old bash workaround, see above.

     

       
248
       
248
       
-
       


     

       
249
       
249
       
-
       
# if a cc-wrapper-hook exists, run it.

     

       
250
       
250
       
-
       
if [[ -e @out@/nix-support/cc-wrapper-hook ]]; then

     

       
251
       
251
       
-
       
    compiler=@prog@

     

       
252
       
252
       
-
       
    source @out@/nix-support/cc-wrapper-hook

     

       
253
       
253
       
-
       
fi

     

       
254
       
254
       
 
       


     

       
255
       
255
       
 
       
if (( "${NIX_CC_USE_RESPONSE_FILE:-@use_response_file_by_default@}" >= 1 )); then

     

       
256
       
256
       
 
       
    responseFile=$(@mktemp@ "${TMPDIR:-/tmp}/cc-params.XXXXXX")