[llvm] 3f64ba5 - [OCaml] Try to fix library dependencies (#171470)

[via llvm-commits]

Author: Nikita Popov
Date: 2025-12-22T10:09:21+01:00
New Revision: 3f64ba5b5ba88d31df93b4a5a72081aae73ce623

URL: https://github.com/llvm/llvm-project/commit/3f64ba5b5ba88d31df93b4a5a72081aae73ce623
DIFF: https://github.com/llvm/llvm-project/commit/3f64ba5b5ba88d31df93b4a5a72081aae73ce623.diff

LOG: [OCaml] Try to fix library dependencies (#171470)

Whenever I try to change anything in the OCaml bindings, I run into
errors like this when running tests:

```
File
"/home/npopov/repos/llvm-project/build/test/Bindings/OCaml/Output/debuginfo.ml.tmp/Testsuite.ml",
line 1:
    Warning 70 [missing-mli]: Cannot find interface file.

File
"/home/npopov/repos/llvm-project/build/test/Bindings/OCaml/Output/debuginfo.ml.tmp/debuginfo.ml",
line 1:
Error: The files
"/home/npopov/repos/llvm-project/build/lib/ocaml/llvm/llvm.cmi"
and
"/home/npopov/repos/llvm-project/build/lib/ocaml/llvm/llvm_debuginfo.cmi"
           make inconsistent assumptions over interface "Llvm"
```

The only reliable way of getting rid of these I have found is to do an
`rm -rf build` and just rebuild everything.

The root cause of this issue is that we currently add
target-dependencies between ocaml modules, but we don't have file-level
dependencies. This means that everything gets built in the correct
order, but targets don't get rebuilt if a dependency is changed.

To fix this, add file-level dependencies to the custom command. These
are generated via a target property that stores the ocaml outputs of the
target.

Added: 
    

Modified: 
    llvm/cmake/modules/AddOCaml.cmake

Removed: 
    


################################################################################
diff  --git a/llvm/cmake/modules/AddOCaml.cmake b/llvm/cmake/modules/AddOCaml.cmake
index 2d9116b08a526..9a393ae3b7474 100644
--- a/llvm/cmake/modules/AddOCaml.cmake
+++ b/llvm/cmake/modules/AddOCaml.cmake
@@ -57,9 +57,12 @@ function(add_ocaml_library name)
                   "-ccopt" "-Wl,-rpath,\\$CAMLORIGIN/../.."
                   ${ocaml_pkgs})
 
+  set(ocaml_dep_inputs)
   foreach( ocaml_dep ${ARG_OCAMLDEP} )
     get_target_property(dep_ocaml_flags "ocaml_${ocaml_dep}" OCAML_FLAGS)
     list(APPEND ocaml_flags ${dep_ocaml_flags})
+    get_target_property(dep_ocaml_outputs "ocaml_${ocaml_dep}" OCAML_OUTPUTS)
+    list(APPEND ocaml_dep_inputs ${dep_ocaml_outputs})
   endforeach()
 
   if( NOT BUILD_SHARED_LIBS )
@@ -157,7 +160,7 @@ function(add_ocaml_library name)
     OUTPUT ${ocaml_outputs}
     COMMAND "${OCAMLFIND}" "ocamlmklib" "-ocamlcflags" "-bin-annot"
       "-o" "${name}" ${ocaml_flags} ${ocaml_params}
-    DEPENDS ${ocaml_inputs} ${c_outputs}
+    DEPENDS ${ocaml_inputs} ${ocaml_dep_inputs} ${c_outputs}
     COMMENT "Building OCaml library ${name}"
     VERBATIM)
 
@@ -168,7 +171,7 @@ function(add_ocaml_library name)
             "-I" "${LLVM_LIBRARY_DIR}/ocaml/llvm/"
             "-dump" "${bin}/${name}.odoc"
             ${ocaml_pkgs} ${ocaml_inputs}
-    DEPENDS ${ocaml_inputs} ${ocaml_outputs}
+    DEPENDS ${ocaml_inputs} ${ocaml_dep_inputs} ${ocaml_outputs}
     COMMENT "Building OCaml documentation for ${name}"
     VERBATIM)
 
@@ -180,6 +183,8 @@ function(add_ocaml_library name)
     OCAML_FLAGS "-I;${bin}")
   set_target_properties("ocaml_${name}" PROPERTIES
     OCAML_ODOC "${bin}/${name}.odoc")
+  set_target_properties("ocaml_${name}" PROPERTIES
+    OCAML_OUTPUTS "${ocaml_outputs}")
 
   foreach( ocaml_dep ${ARG_OCAMLDEP} )
     add_dependencies("ocaml_${name}" "ocaml_${ocaml_dep}")