rules: Support staging debug artifacts in install-with-deps rule

The existing rule is extended to also stage source files if in
debug mode, in order for a debugger to be able to find all needed
symbols. Conflicting paths are allowed; in case of conflicts, the
file from the closest target in the dependency chain wins.

2 files changed, 94 insertions, 2 deletions

diff --git a/CC/EXPRESSIONS b/CC/EXPRESSIONS
index b3ce957..067fc0d 100644
--- a/CC/EXPRESSIONS
+++ b/CC/EXPRESSIONS
@@ -188,6 +188,40 @@
       }
     }
   }
+, "debug-srcs":
+  { "doc": ["Collect debug dependencies (sources) 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": "map_union"
+    , "$1":
+      { "type": "++"
+      , "$1":
+        { "type": "foreach"
+        , "var": "fieldname"
+        , "range": {"type": "var", "name": "deps-fieldnames"}
+        , "body":
+          { "type": "++"
+          , "$1":
+            { "type": "let*"
+            , "bindings":
+              [ ["provider", "debug-srcs"]
+              , ["transition", {"type": "var", "name": "deps-transition"}]
+              , ["default", {"type": "empty_map"}]
+              ]
+            , "body": [{"type": "CALL_EXPRESSION", "name": "provider_list"}]
+            }
+          }
+        }
+      }
+    }
+  }
 , "compile-deps":
   { "doc": ["Collect compile dependencies (headers) from given target_fields"]
   , "vars": ["deps-fieldnames", "deps-transition"]
@@ -1025,6 +1059,7 @@
     , "ADD_CXXFLAGS"
     , "AR"
     , "ENV"
+    , "DEBUG"
     , "name"
     , "pure C"
     , "srcs"
@@ -1047,6 +1082,7 @@
     , "cflags-files-deps": "cflags-files-deps"
     , "ldflags-files-deps": "ldflags-files-deps"
     , "lib artifact": "lib artifact"
+    , "debug-srcs": "debug-srcs"
     }
   , "expression":
     { "type": "let*"
@@ -1085,6 +1121,19 @@
       , [ "ldflags-files"
         , {"type": "CALL_EXPRESSION", "name": "ldflags-files-deps"}
         ]
+      , [ "debug-srcs"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "DEBUG"}
+          , "then":
+            { "type": "map_union"
+            , "$1":
+              [ {"type": "CALL_EXPRESSION", "name": "debug-srcs"}
+              , {"type": "var", "name": "srcs"}
+              ]
+            }
+          , "else": {"type": "empty_map"}
+          }
+        ]
       , ["deps-fieldnames", {"type": "var", "name": "public-fieldnames"}]
       , ["compile-deps", {"type": "CALL_EXPRESSION", "name": "compile-deps"}]
       , [ "compile-args"
@@ -1123,6 +1172,7 @@
               , "link-deps"
               , "link-args"
               , "package"
+              , "debug-srcs"
               ]
             }
           , { "type": "var"
@@ -1304,6 +1354,7 @@
     , "ADD_CFLAGS"
     , "ADD_CXXFLAGS"
     , "ENV"
+    , "DEBUG"
     , "name"
     , "pure C"
     , "srcs"
@@ -1321,6 +1372,7 @@
     , "cflags-files-deps": "cflags-files-deps"
     , "ldflags-files-deps": "ldflags-files-deps"
     , "binary": "bin artifact"
+    , "debug-srcs": "debug-srcs"
     }
   , "expression":
     { "type": "let*"
@@ -1354,11 +1406,24 @@
         , {"type": "CALL_EXPRESSION", "name": "ldflags-files-deps"}
         ]
       , ["package", {"type": "singleton_map", "key": "to_bin", "value": true}]
+      , [ "debug-srcs"
+        , { "type": "if"
+          , "cond": {"type": "var", "name": "DEBUG"}
+          , "then":
+            { "type": "map_union"
+            , "$1":
+              [ {"type": "CALL_EXPRESSION", "name": "debug-srcs"}
+              , {"type": "var", "name": "srcs"}
+              ]
+            }
+          , "else": {"type": "empty_map"}
+          }
+        ]
       ]
     , "body":
       { "type": "RESULT"
       , "artifacts": {"type": "CALL_EXPRESSION", "name": "binary"}
-      , "provides": {"type": "env", "vars": ["package"]}
+      , "provides": {"type": "env", "vars": ["package", "debug-srcs"]}
       }
     }
   }
@@ -1400,6 +1465,13 @@
                       ]
                     }
                   ]
+                , [ "debug-srcs"
+                  , { "type": "DEP_PROVIDES"
+                    , "dep": {"type": "var", "name": "target"}
+                    , "provider": "debug-srcs"
+                    , "default": {"type": "empty_map"}
+                    }
+                  ]
                 ]
               , "body":
                 { "type": "if"
@@ -1554,6 +1626,10 @@
                         , "subdir": {"type": "var", "name": "pc-install-dir"}
                         , "$1": {"type": "var", "name": "pkg-config"}
                         }
+                      , { "type": "to_subdir"
+                        , "subdir": "debug-src"
+                        , "$1": {"type": "var", "name": "debug-srcs"}
+                        }
                       ]
                     }
                   }
diff --git a/CC/RULES b/CC/RULES
index a5202cf..a2ced03 100644
--- a/CC/RULES
+++ b/CC/RULES
@@ -350,6 +350,7 @@
     , "ADD_CXXFLAGS"
     , "AR"
     , "ENV"
+    , "DEBUG"
     ]
   , "implicit": {"defaults": ["defaults"]}
   , "field_doc":
@@ -443,6 +444,7 @@
       , "If None, the respective value from [\"CC\", \"defaults\"] will be taken."
       ]
     , "ENV": ["The environment for any action generated."]
+    , "DEBUG": ["Compute the debug-stage, needed for local debugging."]
     }
   , "artifacts_doc":
     ["The actual library (libname.a) staged in the specified directory"]
@@ -460,6 +462,7 @@
       [ "List of strings that have to be added to the command line for linking actions"
       , "in targets depending on this library"
       ]
+    , "debug-srcs": ["Map of all dependencies' sources needed for debugging."]
     }
   , "anonymous":
     { "proto-deps":
@@ -569,7 +572,15 @@
     , "private-ldflags"
     ]
   , "config_vars":
-    ["CC", "CXX", "CFLAGS", "CXXFLAGS", "ADD_CFLAGS", "ADD_CXXFLAGS", "ENV"]
+    [ "CC"
+    , "CXX"
+    , "CFLAGS"
+    , "CXXFLAGS"
+    , "ADD_CFLAGS"
+    , "ADD_CXXFLAGS"
+    , "ENV"
+    , "DEBUG"
+    ]
   , "implicit": {"defaults": ["defaults"]}
   , "field_doc":
     { "name": ["The name of the binary"]
@@ -626,9 +637,12 @@
       , "taken from the [\"CC\", \"defaults\"] target"
       ]
     , "ENV": ["The environment for any action generated."]
+    , "DEBUG": ["Compute the debug-stage, needed for local debugging."]
     }
   , "artifacts_doc": ["The final binary, staged to the given directory"]
   , "runfiles_doc": ["None"]
+  , "provides_doc":
+    {"debug-srcs": ["Map of all dependencies' sources needed for debugging."]}
   , "anonymous":
     { "private-proto-deps":
       { "target": "private-proto"
@@ -704,6 +718,8 @@
     , "the target, artifacts and dependencies will be installed to"
     , "subdirectories \"bin\", \"include\", and \"lib\". For library targets,"
     , "a pkg-config file is generated and provided in \"lib/pkgconfig\"."
+    , "In debug mode, sources needed for local debugging will be installed to"
+    , "subdirectory \"debug-src\"."
     ]
   , "config_vars": ["PREFIX"]
   , "target_fields": ["targets"]