Merge commit '95284ec611a53ca9c7925aad4bbe3f6561de018a' into shared-rules

8 files changed, 547 insertions, 9 deletions

diff --git a/README.md b/README.md
index c2f4892..ee6b3b0 100644
--- a/README.md
+++ b/README.md
@@ -12,12 +12,14 @@ A C++ library
 | `"cflags"` | List of compile flags set for this target and its consumers. |
 | `"private-cflags"` | List of compile flags set for source files local to this target. |
 | `"private-ldflags"` | Additional linker flags for linking external libraries (not built by this tool, typically system libraries). |
+| `"soversion"` | The SOVERSION for shared libraries. Individual version components are joined with `"."`. |
 | `"srcs"` | The source files of the library. |
 | `"hdrs"` | Any public header files of the library. |
 | `"private-hdrs"` | Any header files that only need to be present when compiling the source files, but are not needed for any consumer of the library. |
 | `"deps"` | Any other libraries this library depends upon. |
 | `"private-deps"` | Any other libraries this library depends upon but does not include in its public headers. |
 | `"proto"` | Any `["proto", "library"]` this target depends upon directly. The creation of C++ bindings for this proto library as well as of its dependencies will be taken care of (as anonymous targets, so no duplicate work will be carried out, even if the same proto library is used at various places). |
+| `"shared"` | If non-empty, produce a shared instead of a static library. |
 
 ## Rule `["CC", "binary"]`
 
diff --git a/rules/CC/EXPRESSIONS b/rules/CC/EXPRESSIONS
index 7beac0a..2998fa8 100644
--- a/rules/CC/EXPRESSIONS
+++ b/rules/CC/EXPRESSIONS
@@ -82,6 +82,21 @@
     , "body": {"type": "CALL_EXPRESSION", "name": "list_provider"}
     }
   }
+, "default-LDFLAGS":
+  { "vars": ["defaults-transition"]
+  , "imports": {"list_provider": ["./", "..", "field_list_provider"]}
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ ["fieldname", "defaults"]
+      , ["provider", "LDFLAGS"]
+      , [ "transition"
+        , {"type": "var", "name": "defaults-transition", "default": null}
+        ]
+      ]
+    , "body": {"type": "CALL_EXPRESSION", "name": "list_provider"}
+    }
+  }
 , "default-ENV":
   { "vars": ["defaults-transition"]
   , "imports": {"provider_list": ["./", "..", "field_provider_list"]}
@@ -255,6 +270,69 @@
       }
     }
   }
+, "run-libs-deps":
+  { "doc": ["Collect runtime libraries from given target_fields"]
+  , "vars": ["deps-fieldnames", "deps-transition"]
+  , "vars_doc":
+    { "deps-fieldnames":
+      ["List of target_field names to collect dependencies from."]
+    , "deps-transition":
+      ["The optional configuration transition for the targets."]
+    }
+  , "imports": {"provider_list": ["./", "..", "field_provider_list"]}
+  , "expression":
+    { "type": "to_subdir"
+    , "flat": true
+    , "$1":
+      { "type": "disjoint_map_union"
+      , "$1":
+        { "type": "++"
+        , "$1":
+          { "type": "foreach"
+          , "var": "fieldname"
+          , "range": {"type": "var", "name": "deps-fieldnames"}
+          , "body":
+            { "type": "let*"
+            , "bindings":
+              [ ["provider", "run-libs"]
+              , ["default", {"type": "empty_map"}]
+              , ["transition", {"type": "var", "name": "deps-transition"}]
+              ]
+            , "body": {"type": "CALL_EXPRESSION", "name": "provider_list"}
+            }
+          }
+        }
+      }
+    }
+  }
+, "run-libs-args-deps":
+  { "doc":
+    ["Collect runtime libraries link arguments from given target_fields"]
+  , "vars": ["deps-fieldnames", "deps-transition"]
+  , "vars_doc":
+    { "deps-fieldnames":
+      ["List of target_field names to collect arguments from."]
+    , "deps-transition":
+      ["The optional configuration transition for the targets."]
+    }
+  , "imports": {"list_provider": ["./", "..", "field_list_provider"]}
+  , "expression":
+    { "type": "++"
+    , "$1":
+      { "type": "foreach"
+      , "var": "fieldname"
+      , "range": {"type": "var", "name": "deps-fieldnames"}
+      , "body":
+        { "type": "let*"
+        , "bindings":
+          [ ["provider", "run-libs-args"]
+          , ["transition", {"type": "var", "name": "deps-transition"}]
+          ]
+        , "body": {"type": "CALL_EXPRESSION", "name": "list_provider"}
+        }
+      }
+    }
+  }
 , "objects":
   { "vars":
     [ "COMPILER"
@@ -403,12 +481,21 @@
     }
   }
 , "flags-cc":
-  { "vars": ["CFLAGS", "ADD_CFLAGS", "defaults-transition"]
+  { "vars":
+    [ "CFLAGS"
+    , "ADD_CFLAGS"
+    , "BUILD_POSITION_INDEPENDENT"
+    , "defaults-transition"
+    ]
   , "imports": {"default-CFLAGS": "default-CFLAGS"}
   , "expression":
     { "type": "++"
     , "$1":
-      [ { "type": "var"
+      [ { "type": "if"
+        , "cond": {"type": "var", "name": "BUILD_POSITION_INDEPENDENT"}
+        , "then": ["-fPIC"]
+        }
+      , { "type": "var"
         , "name": "CFLAGS"
         , "default": {"type": "CALL_EXPRESSION", "name": "default-CFLAGS"}
         }
@@ -417,12 +504,21 @@
     }
   }
 , "flags-cxx":
-  { "vars": ["CXXFLAGS", "ADD_CXXFLAGS", "defaults-transition"]
+  { "vars":
+    [ "CXXFLAGS"
+    , "ADD_CXXFLAGS"
+    , "BUILD_POSITION_INDEPENDENT"
+    , "defaults-transition"
+    ]
   , "imports": {"default-CXXFLAGS": "default-CXXFLAGS"}
   , "expression":
     { "type": "++"
     , "$1":
-      [ { "type": "var"
+      [ { "type": "if"
+        , "cond": {"type": "var", "name": "BUILD_POSITION_INDEPENDENT"}
+        , "then": ["-fPIC"]
+        }
+      , { "type": "var"
         , "name": "CXXFLAGS"
         , "default": {"type": "CALL_EXPRESSION", "name": "default-CXXFLAGS"}
         }
@@ -436,6 +532,7 @@
     , "CXXFLAGS"
     , "ADD_CFLAGS"
     , "ADD_CXXFLAGS"
+    , "BUILD_POSITION_INDEPENDENT"
     , "pure C"
     , "defaults-transition"
     ]
@@ -457,6 +554,7 @@
     , "ADD_CXXFLAGS"
     , "AR"
     , "ENV"
+    , "BUILD_POSITION_INDEPENDENT"
     , "name"
     , "pure C"
     , "srcs"
@@ -575,6 +673,7 @@
     , "ADD_CXXFLAGS"
     , "AR"
     , "ENV"
+    , "BUILD_POSITION_INDEPENDENT"
     , "name"
     , "pure C"
     , "srcs"
@@ -593,6 +692,8 @@
     , "compile-args-deps": "compile-args-deps"
     , "link-deps": "link-deps"
     , "link-args-deps": "link-args-deps"
+    , "run-libs-deps": "run-libs-deps"
+    , "run-libs-args-deps": "run-libs-args-deps"
     , "lib artifact": "lib artifact"
     }
   , "expression":
@@ -626,6 +727,12 @@
             }
           }
         ]
+      , ["run-libs", {"type": "CALL_EXPRESSION", "name": "run-libs-deps"}]
+      , [ "run-libs-args"
+        , { "type": "nub_right"
+          , "$1": {"type": "CALL_EXPRESSION", "name": "run-libs-args-deps"}
+          }
+        ]
       , ["deps-fieldnames", {"type": "var", "name": "public-fieldnames"}]
       , ["compile-deps", {"type": "CALL_EXPRESSION", "name": "compile-deps"}]
       , [ "compile-args"
@@ -649,7 +756,277 @@
         , "$1":
           [ { "type": "env"
             , "vars":
-              ["compile-deps", "compile-args", "link-deps", "link-args"]
+              [ "compile-deps"
+              , "compile-args"
+              , "link-deps"
+              , "link-args"
+              , "run-libs"
+              , "run-libs-args"
+              ]
+            }
+          , { "type": "var"
+            , "name": "extra-provides"
+            , "default": {"type": "empty_map"}
+            }
+          ]
+        }
+      }
+    }
+  }
+, "shared artifact":
+  { "vars":
+    [ "CC"
+    , "CXX"
+    , "CFLAGS"
+    , "CXXFLAGS"
+    , "LDFLAGS"
+    , "ADD_CFLAGS"
+    , "ADD_CXXFLAGS"
+    , "ADD_LDFLAGS"
+    , "ENV"
+    , "name"
+    , "pure C"
+    , "srcs"
+    , "hdrs"
+    , "private-hdrs"
+    , "soversion"
+    , "compile-deps"
+    , "compile-args"
+    , "link-deps"
+    , "link-args"
+    , "run-libs"
+    , "run-libs-args"
+    , "defaults-transition"
+    ]
+  , "imports":
+    { "compiler": "compiler"
+    , "flags": "flags"
+    , "objects": "objects"
+    , "default-LDFLAGS": "default-LDFLAGS"
+    , "default-ENV": "default-ENV"
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ ["BUILD_POSITION_INDEPENDENT", true]
+      , ["COMPILER", {"type": "CALL_EXPRESSION", "name": "compiler"}]
+      , [ "COMPILE_FLAGS"
+        , { "type": "++"
+          , "$1":
+            [ {"type": "CALL_EXPRESSION", "name": "flags"}
+            , {"type": "var", "name": "compile-args"}
+            ]
+          }
+        ]
+      , [ "LDFLAGS"
+        , { "type": "++"
+          , "$1":
+            [ { "type": "var"
+              , "name": "LDFLAGS"
+              , "default":
+                {"type": "CALL_EXPRESSION", "name": "default-LDFLAGS"}
+              }
+            , {"type": "var", "name": "ADD_LDFLAGS", "default": []}
+            ]
+          }
+        ]
+      , [ "ENV"
+        , { "type": "map_union"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "CALL_EXPRESSION", "name": "default-ENV"}
+              , [ { "type": "var"
+                  , "name": "ENV"
+                  , "default": {"type": "empty_map"}
+                  }
+                ]
+              ]
+            }
+          }
+        ]
+      , ["objects", {"type": "CALL_EXPRESSION", "name": "objects"}]
+      , [ "base name"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "objects"}
+          , "then":
+            { "type": "assert_non_empty"
+            , "msg": "A name has to be provided for non-header-only libraries"
+            , "$1": {"type": "var", "name": "name"}
+            }
+          , "else": {"type": "var", "name": "name"}
+          }
+        ]
+      , [ "libname"
+        , { "type": "join"
+          , "$1": ["lib", {"type": "var", "name": "base name"}, ".so"]
+          }
+        ]
+      , [ "libname"
+        , { "type": "join"
+          , "separator": "."
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ [{"type": "var", "name": "libname"}]
+              , {"type": "var", "name": "soversion"}
+              ]
+            }
+          }
+        ]
+      , [ "lib"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "objects"}
+          , "else": {"type": "empty_map"}
+          , "then":
+            { "type": "ACTION"
+            , "outs": [{"type": "var", "name": "libname"}]
+            , "inputs":
+              { "type": "map_union"
+              , "$1":
+                [ {"type": "var", "name": "objects"}
+                , {"type": "var", "name": "link-deps"}
+                , {"type": "var", "name": "run-libs"}
+                ]
+              }
+            , "env":
+              {"type": "var", "name": "ENV", "default": {"type": "empty_map"}}
+            , "cmd":
+              { "type": "++"
+              , "$1":
+                [ [ {"type": "var", "name": "COMPILER"}
+                  , "-shared"
+                  , "-Wl,-rpath,$ORIGIN"
+                  , "-Wl,-rpath,$ORIGIN/../lib"
+                  , { "type": "join"
+                    , "$1":
+                      ["-Wl,-soname,", {"type": "var", "name": "libname"}]
+                    }
+                  ]
+                , {"type": "var", "name": "COMPILE_FLAGS"}
+                , {"type": "var", "name": "LDFLAGS"}
+                , ["-o", {"type": "var", "name": "libname"}]
+                , {"type": "keys", "$1": {"type": "var", "name": "objects"}}
+                , {"type": "var", "name": "link-args"}
+                , {"type": "var", "name": "run-libs-args"}
+                ]
+              }
+            }
+          }
+        ]
+      ]
+    , "body": {"type": "var", "name": "lib"}
+    }
+  }
+, "shared result":
+  { "vars":
+    [ "CC"
+    , "CXX"
+    , "CFLAGS"
+    , "CXXFLAGS"
+    , "LDFLAGS"
+    , "ADD_CXXFLAGS"
+    , "ADD_CFLAGS"
+    , "ADD_LDFLAGS"
+    , "ENV"
+    , "name"
+    , "pure C"
+    , "srcs"
+    , "hdrs"
+    , "private-hdrs"
+    , "cflags"
+    , "private-cflags"
+    , "private-ldflags"
+    , "soversion"
+    , "extra-provides"
+    , "deps-transition"
+    , "public-fieldnames"
+    , "private-fieldnames"
+    ]
+  , "imports":
+    { "compile-deps": "compile-deps"
+    , "compile-args-deps": "compile-args-deps"
+    , "link-deps": "link-deps"
+    , "link-args-deps": "link-args-deps"
+    , "run-libs-deps": "run-libs-deps"
+    , "run-libs-args-deps": "run-libs-args-deps"
+    , "shared artifact": "shared artifact"
+    }
+  , "expression":
+    { "type": "let*"
+    , "bindings":
+      [ ["deps-fieldnames", {"type": "var", "name": "private-fieldnames"}]
+      , ["compile-deps", {"type": "CALL_EXPRESSION", "name": "compile-deps"}]
+      , [ "compile-args"
+        , { "type": "nub_right"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "var", "name": "cflags"}
+              , {"type": "var", "name": "private-cflags"}
+              , {"type": "CALL_EXPRESSION", "name": "compile-args-deps"}
+              ]
+            }
+          }
+        ]
+      , ["link-deps", {"type": "CALL_EXPRESSION", "name": "link-deps"}]
+      , ["link-args", {"type": "CALL_EXPRESSION", "name": "link-args-deps"}]
+      , ["run-libs", {"type": "CALL_EXPRESSION", "name": "run-libs-deps"}]
+      , [ "run-libs-args"
+        , { "type": "nub_right"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "var", "name": "private-ldflags", "default": []}
+              , {"type": "CALL_EXPRESSION", "name": "run-libs-args-deps"}
+              ]
+            }
+          }
+        ]
+      , ["lib", {"type": "CALL_EXPRESSION", "name": "shared artifact"}]
+      , ["deps-fieldnames", {"type": "var", "name": "public-fieldnames"}]
+      , ["compile-deps", {"type": "CALL_EXPRESSION", "name": "compile-deps"}]
+      , [ "compile-args"
+        , { "type": "nub_right"
+          , "$1":
+            { "type": "++"
+            , "$1":
+              [ {"type": "var", "name": "cflags"}
+              , {"type": "CALL_EXPRESSION", "name": "compile-args-deps"}
+              ]
+            }
+          }
+        ]
+      , ["link-deps", {"type": "CALL_EXPRESSION", "name": "link-deps"}]
+      , ["link-args", {"type": "CALL_EXPRESSION", "name": "link-args-deps"}]
+      , [ "run-libs"
+        , { "type": "map_union"
+          , "$1":
+            [ {"type": "var", "name": "lib"}
+            , {"type": "var", "name": "run-libs"}
+            ]
+          }
+        ]
+      , [ "run-libs-args"
+        , {"type": "keys", "$1": {"type": "var", "name": "lib"}}
+        ]
+      ]
+    , "body":
+      { "type": "RESULT"
+      , "artifacts": {"type": "var", "name": "lib"}
+      , "runfiles": {"type": "var", "name": "hdrs"}
+      , "provides":
+        { "type": "map_union"
+        , "$1":
+          [ { "type": "env"
+            , "vars":
+              [ "compile-deps"
+              , "compile-args"
+              , "link-deps"
+              , "link-args"
+              , "run-libs"
+              , "run-libs-args"
+              ]
             }
           , { "type": "var"
             , "name": "extra-provides"
@@ -667,9 +1044,12 @@
     , "CXX"
     , "CFLAGS"
     , "CXXFLAGS"
+    , "LDFLAGS"
     , "ADD_CFLAGS"
     , "ADD_CXXFLAGS"
+    , "ADD_LDFLAGS"
     , "ENV"
+    , "BUILD_POSITION_INDEPENDENT"
     , "name"
     , "pure C"
     , "srcs"
@@ -679,6 +1059,8 @@
     , "compile-args"
     , "link-deps"
     , "link-args"
+    , "run-libs"
+    , "run-libs-args"
     , "defaults-transition"
     ]
   , "imports":
@@ -686,6 +1068,7 @@
     , "flags": "flags"
     , "objects": "objects"
     , "default-ENV": "default-ENV"
+    , "default-LDFLAGS": "default-LDFLAGS"
     }
   , "expression":
     { "type": "let*"
@@ -699,6 +1082,18 @@
             ]
           }
         ]
+      , [ "LDFLAGS"
+        , { "type": "++"
+          , "$1":
+            [ { "type": "var"
+              , "name": "LDFLAGS"
+              , "default":
+                {"type": "CALL_EXPRESSION", "name": "default-LDFLAGS"}
+              }
+            , {"type": "var", "name": "ADD_LDFLAGS", "default": []}
+            ]
+          }
+        ]
       , [ "ENV"
         , { "type": "map_union"
           , "$1":
@@ -749,17 +1144,22 @@
             , "$1":
               [ {"type": "var", "name": "objects"}
               , {"type": "var", "name": "link-deps"}
+              , {"type": "var", "name": "run-libs"}
               ]
             }
           , "cmd":
             { "type": "++"
             , "$1":
               [ [ {"type": "var", "name": "COMPILER"}
+                , "-Wl,-rpath,$ORIGIN"
+                , "-Wl,-rpath,$ORIGIN/../lib"
                 , "-o"
                 , {"type": "var", "name": "binpath"}
                 ]
               , {"type": "var", "name": "COMPILE_FLAGS"}
+              , {"type": "var", "name": "LDFLAGS"}
               , {"type": "var", "name": "link-args"}
+              , {"type": "var", "name": "run-libs-args"}
               ]
             }
           , "env": {"type": "var", "name": "ENV"}
@@ -776,9 +1176,12 @@
     , "CXX"
     , "CFLAGS"
     , "CXXFLAGS"
+    , "LDFLAGS"
     , "ADD_CFLAGS"
     , "ADD_CXXFLAGS"
+    , "ADD_LDFLAGS"
     , "ENV"
+    , "BUILD_POSITION_INDEPENDENT"
     , "name"
     , "pure C"
     , "srcs"
@@ -793,6 +1196,8 @@
     , "compile-args-deps": "compile-args-deps"
     , "link-deps": "link-deps"
     , "link-args-deps": "link-args-deps"
+    , "run-libs-deps": "run-libs-deps"
+    , "run-libs-args-deps": "run-libs-args-deps"
     , "binary": "bin artifact"
     }
   , "expression":
@@ -820,10 +1225,15 @@
             }
           }
         ]
+      , ["run-libs", {"type": "CALL_EXPRESSION", "name": "run-libs-deps"}]
+      , [ "run-libs-args"
+        , {"type": "CALL_EXPRESSION", "name": "run-libs-args-deps"}
+        ]
       ]
     , "body":
       { "type": "RESULT"
       , "artifacts": {"type": "CALL_EXPRESSION", "name": "binary"}
+      , "provides": {"type": "env", "vars": ["run-libs"]}
       }
     }
   }
diff --git a/rules/CC/RULES b/rules/CC/RULES
index 3bfd200..4d90adc 100644
--- a/rules/CC/RULES
+++ b/rules/CC/RULES
@@ -12,8 +12,10 @@
     , "CXX"
     , "CFLAGS"
     , "CXXFLAGS"
+    , "LDFLAGS"
     , "ADD_CFLAGS"
     , "ADD_CXXFLAGS"
+    , "ADD_LDFLAGS"
     , "AR"
     , "PATH"
     ]
@@ -25,6 +27,7 @@
       , ["CXX", {"type": "FIELD", "name": "CXX"}]
       , ["CFLAGS", {"type": "FIELD", "name": "CFLAGS"}]
       , ["CXXFLAGS", {"type": "FIELD", "name": "CXXFLAGS"}]
+      , ["LDFLAGS", {"type": "FIELD", "name": "LDFLAGS"}]
       , ["AR", {"type": "FIELD", "name": "AR"}]
       , ["PATH", {"type": "FIELD", "name": "PATH"}]
       , ["provider", "CC"]
@@ -99,12 +102,20 @@
             ]
           }
         ]
+      , [ "LDFLAGS"
+        , { "type": "++"
+          , "$1":
+            [ {"type": "var", "name": "LDFLAGS"}
+            , {"type": "FIELD", "name": "ADD_LDFLAGS"}
+            ]
+          }
+        ]
       ]
     , "body":
       { "type": "RESULT"
       , "provides":
         { "type": "env"
-        , "vars": ["CC", "CXX", "CFLAGS", "CXXFLAGS", "AR", "ENV"]
+        , "vars": ["CC", "CXX", "CFLAGS", "CXXFLAGS", "LDFLAGS", "AR", "ENV"]
         }
       }
     }
@@ -122,16 +133,21 @@
     , "cflags"
     , "private-cflags"
     , "private-ldflags"
+    , "soversion"
     ]
+  , "config_fields": ["shared"]
   , "config_vars":
     [ "CC"
     , "CXX"
     , "CFLAGS"
     , "CXXFLAGS"
+    , "LDFLAGS"
     , "ADD_CFLAGS"
     , "ADD_CXXFLAGS"
+    , "ADD_LDFLAGS"
     , "AR"
     , "ENV"
+    , "BUILD_POSITION_INDEPENDENT"
     ]
   , "implicit": {"defaults": ["defaults"]}
   , "field_doc":
@@ -181,6 +197,11 @@
       , "duplicate work will be carried out, even if the same proto library"
       , "is used at various places)."
       ]
+    , "shared": ["If non-empty, produce a shared instead of a static library."]
+    , "soversion":
+      [ "The SOVERSION for shared libraries. Individual version components are"
+      , "joined with \".\"."
+      ]
     }
   , "config_doc":
     { "CC":
@@ -203,6 +224,12 @@
       , "adapting the default target [\"CC\", \"defaults\"] is the better"
       , "choice."
       ]
+    , "LDFLAGS":
+      [ "The linker flags to be used instead of the default ones."
+      , "For libraries that should be built in a non-standard way; usually"
+      , "adapting the default target [\"CC\", \"defaults\"] is the better"
+      , "choice."
+      ]
     , "ADD_CFLAGS":
       [ "The flags to add to the default ones for CC."
       , "For libraries that should be built in a non-standard way; usually"
@@ -215,11 +242,18 @@
       , "adapting the default target [\"CC\", \"defaults\"] is the better"
       , "choice."
       ]
+    , "ADD_LDFLAGS":
+      [ "The linker flags to add to the default ones."
+      , "For libraries that should be built in a non-standard way; usually"
+      , "adapting the default target [\"CC\", \"defaults\"] is the better"
+      , "choice."
+      ]
     , "AR":
       [ "The archive tool to used for creating the library"
       , "If None, the respective value from [\"CC\", \"defaults\"] will be taken."
       ]
     , "ENV": ["The environment for any action generated."]
+    , "BUILD_POSITION_INDEPENDENT": ["Build with -fPIC."]
     }
   , "artifacts_doc":
     ["The actual library (libname.a) staged in the specified directory"]
@@ -249,7 +283,16 @@
       }
     }
   , "imports":
-    {"artifacts": ["./", "..", "field_artifacts"], "result": "lib result"}
+    { "artifacts": ["./", "..", "field_artifacts"]
+    , "static result": "lib result"
+    , "shared result": "shared result"
+    , "fPIC transition": ["transitions", "with fPIC"]
+    }
+  , "config_transitions":
+    { "deps": [{"type": "CALL_EXPRESSION", "name": "fPIC transition"}]
+    , "private-deps": [{"type": "CALL_EXPRESSION", "name": "fPIC transition"}]
+    , "proto-deps": [{"type": "CALL_EXPRESSION", "name": "fPIC transition"}]
+    }
   , "expression":
     { "type": "let*"
     , "bindings":
@@ -318,10 +361,19 @@
           }
         ]
       , ["private-ldflags", {"type": "FIELD", "name": "private-ldflags"}]
+      , ["soversion", {"type": "FIELD", "name": "soversion"}]
+      , [ "deps-transition"
+        , {"type": "CALL_EXPRESSION", "name": "fPIC transition"}
+        ]
       , ["public-fieldnames", ["deps", "proto-deps"]]
       , ["private-fieldnames", ["deps", "private-deps", "proto-deps"]]
       ]
-    , "body": {"type": "CALL_EXPRESSION", "name": "result"}
+    , "body":
+      { "type": "if"
+      , "cond": {"type": "FIELD", "name": "shared"}
+      , "then": {"type": "CALL_EXPRESSION", "name": "shared result"}
+      , "else": {"type": "CALL_EXPRESSION", "name": "static result"}
+      }
     }
   }
 , "binary":
@@ -336,7 +388,17 @@
     , "private-ldflags"
     ]
   , "config_vars":
-    ["CC", "CXX", "CFLAGS", "CXXFLAGS", "ADD_CFLAGS", "ADD_CXXFLAGS", "ENV"]
+    [ "CC"
+    , "CXX"
+    , "CFLAGS"
+    , "CXXFLAGS"
+    , "LDFLAGS"
+    , "ADD_CFLAGS"
+    , "ADD_CXXFLAGS"
+    , "ADD_LDFLAGS"
+    , "ENV"
+    , "BUILD_POSITION_INDEPENDENT"
+    ]
   , "implicit": {"defaults": ["defaults"]}
   , "field_doc":
     { "name": ["The name of the binary"]
@@ -383,6 +445,10 @@
       [ "The flags for CXX to be used instead of the default ones"
       , "taken from the [\"CC\", \"defaults\"] target"
       ]
+    , "LDFLAGS":
+      [ "The linker flags do be used instead of the default ones"
+      , "taken from the [\"CC\", \"defaults\"] target"
+      ]
     , "ADD_CFLAGS":
       [ "The flags to add to the default ones for CC"
       , "taken from the [\"CC\", \"defaults\"] target"
@@ -391,7 +457,12 @@
       [ "The flags to add to the default ones for CXX"
       , "taken from the [\"CC\", \"defaults\"] target"
       ]
+    , "ADD_LDFLAGS":
+      [ "The linker flags to add to the default ones"
+      , "taken from the [\"CC\", \"defaults\"] target"
+      ]
     , "ENV": ["The environment for any action generated."]
+    , "BUILD_POSITION_INDEPENDENT": ["Build with -fPIC."]
     }
   , "artifacts_doc": ["The final binary, staged to the given directory"]
   , "runfiles_doc": ["None"]
diff --git a/rules/CC/TARGETS b/rules/CC/TARGETS
index 2da456b..8860e8b 100644
--- a/rules/CC/TARGETS
+++ b/rules/CC/TARGETS
@@ -4,6 +4,7 @@
   , "CXX": ["c++"]
   , "CFLAGS": []
   , "CXXFLAGS": []
+  , "LDFLAGS": []
   , "AR": ["ar"]
   , "PATH": ["/bin", "/usr/bin"]
   }
diff --git a/rules/CC/test/RULES b/rules/CC/test/RULES
index 3821339..60f33ab 100644
--- a/rules/CC/test/RULES
+++ b/rules/CC/test/RULES
@@ -18,9 +18,12 @@
     , "CXX"
     , "CFLAGS"
     , "CXXFLAGS"
+    , "LDFLAGS"
     , "ADD_CFLAGS"
     , "ADD_CXXFLAGS"
+    , "ADD_LDFLAGS"
     , "ENV"
+    , "BUILD_POSITION_INDEPENDENT"
     , "TEST_ENV"
     , "CC_TEST_LAUNCHER"
     ]
@@ -65,6 +68,10 @@
       [ "The flags for CXX to be used instead of the default ones"
       , "taken from the [\"CC\", \"defaults\"] target"
       ]
+    , "LDFLAGS":
+      [ "The linker flags do be used instead of the default ones"
+      , "taken from the [\"CC\", \"defaults\"] target"
+      ]
     , "ADD_CFLAGS":
       [ "The flags to add to the default ones for CC"
       , "taken from the [\"CC\", \"defaults\"] target"
@@ -73,7 +80,12 @@
       [ "The flags to add to the default ones for CXX"
       , "taken from the [\"CC\", \"defaults\"] target"
       ]
+    , "ADD_LDFLAGS":
+      [ "The linker flags to add to the default ones"
+      , "taken from the [\"CC\", \"defaults\"] target"
+      ]
     , "ENV": ["The environment for any action generated."]
+    , "BUILD_POSITION_INDEPENDENT": ["Build with -fPIC."]
     , "TEST_ENV": ["The environment for executing the test runner."]
     , "CC_TEST_LAUNCHER":
       [ "List of strings representing the launcher that is prepend to the"
@@ -101,6 +113,8 @@
     , "compile-args-deps": ["./", "..", "compile-args-deps"]
     , "link-deps": ["./", "..", "link-deps"]
     , "link-args-deps": ["./", "..", "link-args-deps"]
+    , "run-libs-deps": ["./", "..", "run-libs-deps"]
+    , "run-libs-args-deps": ["./", "..", "run-libs-args-deps"]
     , "binary": ["./", "..", "bin artifact"]
     , "host transition": ["transitions", "for host"]
     }
@@ -173,6 +187,10 @@
             ]
           }
         ]
+      , ["run-libs", {"type": "CALL_EXPRESSION", "name": "run-libs-deps"}]
+      , [ "run-libs-args"
+        , {"type": "CALL_EXPRESSION", "name": "run-libs-args-deps"}
+        ]
       , ["binary", {"type": "CALL_EXPRESSION", "name": "binary"}]
       , [ "staged test binary"
         , { "type": "map_union"
@@ -277,6 +295,7 @@
               , {"type": "var", "name": "test-args"}
               , {"type": "var", "name": "test-launcher"}
               , {"type": "var", "name": "staged test binary"}
+              , {"type": "var", "name": "run-libs"}
               ]
             }
           , "cmd": ["./runner"]
diff --git a/rules/shell/test/EXPRESSIONS b/rules/shell/test/EXPRESSIONS
index d9b1fbc..d1d7e64 100644
--- a/rules/shell/test/EXPRESSIONS
+++ b/rules/shell/test/EXPRESSIONS
@@ -12,6 +12,7 @@
   , "imports":
     { "artifacts_list": ["./", "../..", "field_artifacts_list"]
     , "runfiles_list": ["./", "../..", "field_runfiles_list"]
+    , "map_provider": ["./", "../..", "field_map_provider"]
     }
   , "expression":
     { "type": "let*"
@@ -66,6 +67,19 @@
             }
           }
         ]
+      , [ "run-libs"
+        , { "type": "TREE"
+          , "$1":
+            { "type": "let*"
+            , "bindings":
+              [ ["fieldname", {"type": "var", "name": "deps-fieldname"}]
+              , ["provider", "run-libs"]
+              , ["transition", {"type": "var", "name": "deps-transition"}]
+              ]
+            , "body": {"type": "CALL_EXPRESSION", "name": "map_provider"}
+            }
+          }
+        ]
       , [ "attempt marker"
         , { "type": "if"
           , "cond":
@@ -104,6 +118,10 @@
               , "key": "work"
               , "value": {"type": "var", "name": "deps"}
               }
+            , { "type": "singleton_map"
+              , "key": "libs"
+              , "value": {"type": "var", "name": "run-libs"}
+              }
             , {"type": "var", "name": "runner"}
             , {"type": "var", "name": "test.sh"}
             , {"type": "var", "name": "attempt marker"}
diff --git a/rules/shell/test/test_runner.sh b/rules/shell/test/test_runner.sh
index a99d5b7..97c75ef 100755
--- a/rules/shell/test/test_runner.sh
+++ b/rules/shell/test/test_runner.sh
@@ -25,6 +25,7 @@ echo UNKNOWN > time-stop
 mkdir scratch
 export TEST_TMPDIR=$(realpath scratch)
 export TMPDIR="${TEST_TMPDIR}"
+export LD_LIBRARY_PATH=$(realpath ./libs):$LD_LIBRARY_PATH
 
 # Change to the working directory; note: while unlikely, the test
 # might not have test data, so we have to ensure the presence of
diff --git a/rules/transitions/EXPRESSIONS b/rules/transitions/EXPRESSIONS
index 8ea7550..92be685 100644
--- a/rules/transitions/EXPRESSIONS
+++ b/rules/transitions/EXPRESSIONS
@@ -10,4 +10,20 @@
       }
     }
   }
+, "with fPIC":
+  { "doc":
+    [ "Transition that enables BUILD_POSITION_INDEPENDENT if config_field"
+    , "\"shared\" is not empty."
+    ]
+  , "expression":
+    { "type": "if"
+    , "cond": {"type": "FIELD", "name": "shared"}
+    , "then":
+      { "type": "singleton_map"
+      , "key": "BUILD_POSITION_INDEPENDENT"
+      , "value": true
+      }
+    , "else": {"type": "empty_map"}
+    }
+  }
 }