also cache identify_package and locate_package during package loa…

…ding (#48247)

base/loading.jl

@@ -256,9 +256,12 @@ struct LoadingCache
     env_project_file::Dict{String, Union{Bool, String}}
     project_file_manifest_path::Dict{String, Union{Nothing, String}}
     require_parsed::Set{String}
+    identified_where::Dict{Tuple{PkgId, String}, Union{Nothing, Tuple{PkgId, Union{Nothing, String}}}}
+    identified::Dict{String, Union{Nothing, Tuple{PkgId, Union{Nothing, String}}}}
+    located::Dict{Tuple{PkgId, Union{String, Nothing}}, Union{String, Nothing}}
 end
 const LOADING_CACHE = Ref{Union{LoadingCache, Nothing}}(nothing)
-LoadingCache() = LoadingCache(load_path(), Dict(), Dict(), Dict(), Set())
+LoadingCache() = LoadingCache(load_path(), Dict(), Dict(), Dict(), Set(), Dict(), Dict(), Dict())
 
 
 struct TOMLCache
@@ -311,22 +314,49 @@ is also returned.
 """
 identify_package_env(where::Module, name::String) = identify_package_env(PkgId(where), name)
 function identify_package_env(where::PkgId, name::String)
-    where.name === name && return where, nothing
-    where.uuid === nothing && return identify_package_env(name) # ignore `where`
-    for env in load_path()
-        pkgid = manifest_deps_get(env, where, name)
-        pkgid === nothing && continue # not found--keep looking
-        pkgid.uuid === nothing || return pkgid, env # found in explicit environment--use it
-        return nothing # found in implicit environment--return "not found"
+    cache = LOADING_CACHE[]
+    if cache !== nothing
+        pkg_env = get(cache.identified_where, (where, name), nothing)
+        pkg_env === nothing || return pkg_env
+    end
+    pkg_env = nothing
+    if where.name === name
+        pkg_env = where, nothing
+    elseif where.uuid === nothing
+        pkg_env = identify_package_env(name) # ignore `where`
+    else
+        for env in load_path()
+            pkgid = manifest_deps_get(env, where, name)
+            pkgid === nothing && continue # not found--keep looking
+            if pkgid.uuid !== nothing
+                pkg_env = pkgid, env # found in explicit environment--use it
+            end
+            break # found in implicit environment--return "not found"
+        end
     end
-    return nothing
+    if cache !== nothing
+        cache.identified_where[(where, name)] = pkg_env
+    end
+    return pkg_env
 end
 function identify_package_env(name::String)
+    cache = LOADING_CACHE[]
+    if cache !== nothing
+        pkg_env = get(cache.identified, name, nothing)
+        pkg_env === nothing || return pkg_env
+    end
+    pkg_env = nothing
     for env in load_path()
-        uuid = project_deps_get(env, name)
-        uuid === nothing || return uuid, env # found--return it
+        pkg = project_deps_get(env, name)
+        if pkg !== nothing
+            pkg_env = pkg, env # found--return it
+            break
+        end
     end
-    return nothing
+    if cache !== nothing
+        cache.identified[name] = pkg_env
+    end
+    return pkg_env
 end
 
 _nothing_or_first(x) = x === nothing ? nothing : first(x)
@@ -376,6 +406,12 @@ julia> Base.locate_package(pkg)
 ```
 """
 function locate_package(pkg::PkgId, stopenv::Union{String, Nothing}=nothing)::Union{Nothing,String}
+    cache = LOADING_CACHE[]
+    if cache !== nothing
+        path = get(cache.located, (pkg, stopenv), nothing)
+        path === nothing || return path
+    end
+    path = nothing
     if pkg.uuid === nothing
         for env in load_path()
             # look for the toplevel pkg `pkg.name` in this entry
@@ -386,25 +422,39 @@ function locate_package(pkg::PkgId, stopenv::Union{String, Nothing}=nothing)::Un
                     # pkg.name is present in this directory or project file,
                     # return the path the entry point for the code, if it could be found
                     # otherwise, signal failure
-                    return implicit_manifest_uuid_path(env, pkg)
+                    path = implicit_manifest_uuid_path(env, pkg)
+                    @goto done
                 end
             end
-            stopenv == env && return nothing
+            stopenv == env && @goto done
         end
     else
         for env in load_path()
             path = manifest_uuid_path(env, pkg)
             # missing is used as a sentinel to stop looking further down in envs
-            path === missing && return nothing
-            path === nothing || return entry_path(path, pkg.name)
+            if path === missing
+                path = nothing
+                @goto done
+            end
+            if path !== nothing
+                path = entry_path(path, pkg.name)
+                @goto done
+            end
             stopenv == env && break
         end
         # Allow loading of stdlibs if the name/uuid are given
         # e.g. if they have been explicitly added to the project/manifest
-        path = manifest_uuid_path(Sys.STDLIB, pkg)
-        path isa String && return entry_path(path, pkg.name)
+        mbypath = manifest_uuid_path(Sys.STDLIB, pkg)
+        if mbypath isa String
+            path = entry_path(mbypath, pkg.name)
+            @goto done
+        end
     end
-    return nothing
+    @label done
+    if cache !== nothing
+        cache.located[(pkg, stopenv)] = path
+    end
+    return path
 end
 
 """