Merge pull request #491 from savi-lang/add/prefer-static-link

Add `:prefer static` option for `:ffi_link_lib`.

Author: jemc

core/declarators/declarators.savi

@@ -356,16 +356,6 @@
     :optional
   :body optional
 
-:: Declare a link-time dependency on a particular dynamic library, by name.
-::
-:: This influences the linker arguments that the Savi compiler will use in the
-:: linker invocation when building the binary executable for the program.
-::
-:: For example, declaring `:ffi_link_lib foo` will pass `-lfoo` to the linker.
-:declarator ffi_link_lib
-  :intrinsic
-  :term name Name
-
 :: Declare a link-time dependency on some files written in C code,
 :: which will be compiled and statically linked in the Savi program.
 ::
@@ -389,6 +379,29 @@
   :intrinsic
   :term filenames NameList
 
+:: Declare a link-time dependency on a particular dynamic library, by name.
+::
+:: This influences the linker arguments that the Savi compiler will use in the
+:: linker invocation when building the binary executable for the program.
+::
+:: For example, declaring `:ffi_link_lib foo` will pass `-lfoo` to the linker.
+:declarator ffi_link_lib
+  :intrinsic
+  :term name Name
+  :begins ffi_link_lib
+
+:: Declare that the compiler should prefer to link the above library statically.
+::
+:: This influences the linker arguments that the Savi compiler will use in the
+:: linker invocation when building the binary executable for the program.
+::
+:: If a static version of the library is found, it will be used.
+:: Otherwise, the compiler will fall back to specifying dynamic linking for it.
+:declarator prefer
+  :intrinsic
+  :context ffi_link_lib
+  :term static enum (static)
+
 :: Declare a binding to an unsafe foreign function (FFI), such as a C function.
 ::
 :: It is common to define such bindings on a dedicated private module, which is

src/savi/compiler/binary.cr

@@ -62,6 +62,7 @@ class Savi::Compiler::Binary
 
   # Link a MachO executable for a MacOSX target.
   def link_for_macosx(ctx, target, obj_path, bin_path)
+    lib_paths = [] of String
     link_args = %w{ld64.lld -execute}
 
     # Specify the target architecture.
@@ -72,11 +73,13 @@ class Savi::Compiler::Binary
 
     # Set up explicitly requested library paths.
     each_explicit_lib_path(ctx) { |lib_path|
+      lib_paths << lib_path
       link_args << "-L#{lib_path}"
     }
 
     # Set up the main library paths.
     each_sysroot_lib_path(ctx, target) { |lib_path|
+      lib_paths << lib_path
       link_args << "-L#{lib_path}"
     }
 
@@ -93,7 +96,7 @@ class Savi::Compiler::Binary
     link_args << "-lc++" if ctx.link_cpp_files.any?
 
     # Link any additional libraries indicated by user code.
-    ctx.link_libraries.each { |name| link_args << "-l#{name}" }
+    ctx.link_libraries.each { |name, kind| add_unix_lib(link_args, lib_paths, name, kind) }
 
     # Finally, specify the input object file and the output filename.
     link_args << obj_path
@@ -126,7 +129,7 @@ class Savi::Compiler::Binary
     add_windows_lib(link_args, lib_paths, "WS2_32")  # used by runtime lang/socket.c
 
     # Link any additional libraries indicated by user code.
-    ctx.link_libraries.each { |name| add_windows_lib(link_args, lib_paths, name) }
+    ctx.link_libraries.each { |name, kind| add_windows_lib(link_args, lib_paths, name) }
 
     # Finally, specify the input object file and the output filename.
     link_args << obj_path
@@ -136,20 +139,6 @@ class Savi::Compiler::Binary
     invoke_linker("coff", link_args)
   end
 
-  private def add_windows_lib(link_args, lib_paths, name)
-    if lib_paths.any? { |lib_path|
-      File.exists?(File.join(lib_path, "#{name}.Lib"))
-    }
-      link_args << "-defaultlib:#{name}.Lib"
-    elsif lib_paths.any? { |lib_path|
-      File.exists?(File.join(lib_path, "#{name}.lib"))
-    }
-      link_args << "-defaultlib:#{name}.lib"
-    else
-      link_args << "-defaultlib:#{name.downcase}.lib"
-    end
-  end
-
   # Link an ELF executable for a Linux or FreeBSD target.
   def link_for_linux_or_bsd(ctx, target, obj_path, bin_path)
     link_args = %w{ld.lld}
@@ -172,13 +161,9 @@ class Savi::Compiler::Binary
     # Specify the dynamic linker library, based on the target platform.
     link_args << "-dynamic-linker" << dynamic_linker_for_linux_or_bsd(target)
 
-    # Set up explicitly requested library paths.
-    each_explicit_lib_path(ctx) { |lib_path|
-      link_args << "-L#{lib_path}"
-    }
-
-    # Get the list of lib search paths within the sysroot.
+    # Get the list of lib search paths.
     lib_paths = [] of String
+    each_explicit_lib_path(ctx) { |lib_path| lib_paths << lib_path }
     each_sysroot_lib_path(ctx, target) { |path| lib_paths << path }
     lib_paths.each { |lib_path| link_args << "-L#{lib_path}" }
 
@@ -214,7 +199,7 @@ class Savi::Compiler::Binary
     end
 
     # Link any additional libraries indicated by user code.
-    ctx.link_libraries.each { |name| link_args << "-l#{name}" }
+    ctx.link_libraries.each { |name, kind| add_unix_lib(link_args, lib_paths, name, kind) }
 
     # Finally, specify the input object file and the output filename.
     link_args << obj_path
@@ -224,6 +209,32 @@ class Savi::Compiler::Binary
     invoke_linker("elf", link_args)
   end
 
+  private def add_unix_lib(link_args, lib_paths, name, kind)
+    if kind == :prefer_static
+      found_lib = maybe_find_in_paths(lib_paths, "lib#{name}.a")
+      if found_lib
+        link_args << found_lib
+        return
+      end
+    end
+
+    link_args << "-l#{name}"
+  end
+
+  private def add_windows_lib(link_args, lib_paths, name)
+    if lib_paths.any? { |lib_path|
+      File.exists?(File.join(lib_path, "#{name}.Lib"))
+    }
+      link_args << "-defaultlib:#{name}.Lib"
+    elsif lib_paths.any? { |lib_path|
+      File.exists?(File.join(lib_path, "#{name}.lib"))
+    }
+      link_args << "-defaultlib:#{name}.lib"
+    else
+      link_args << "-defaultlib:#{name.downcase}.lib"
+    end
+  end
+
   # Get the path to the dynamic linker library for a Linux or FreeBSD target.
   def dynamic_linker_for_linux_or_bsd(target) : String
     if target.linux?
@@ -363,12 +374,16 @@ class Savi::Compiler::Binary
   # Given a prioritized list of search paths and a file name, find the file.
   # Raises an error if the file couldn't be found in any of the paths
   def find_in_paths(paths, file_name) : String
+    result = maybe_find_in_paths(paths, file_name)
+    raise "failed to find #{file_name}" if !result
+    result
+  end
+  def maybe_find_in_paths(paths, file_name) : String?
     paths.each { |path|
       file_path = File.join(path, file_name)
       return file_path if File.exists?(file_path)
     }
-
-    raise "failed to find #{file_name}"
+    nil
   end
 
   def invoke_linker(flavor, link_args)

src/savi/compiler/binary_object.cr

@@ -128,7 +128,9 @@ class Savi::Compiler::BinaryObject
     # so we can mark for linking those libraries that are associated to
     # specific functions that come from those libraries.
     ctx.link_libraries_by_foreign_function.each { |ffi_name, lib_name|
-      ctx.link_libraries.add(lib_name) if mod.functions[ffi_name]?
+      next unless mod.functions[ffi_name]?
+      next if ctx.link_libraries[lib_name]?
+      ctx.link_libraries[lib_name] = :dynamic
     }
 
     # Strip debug info from the module if requested.

src/savi/compiler/binary_verona.cr

@@ -39,7 +39,7 @@ class Savi::Compiler::BinaryVerona
       -lc -pthread -ldl -latomic
     }
 
-    ctx.link_libraries.each do |x|
+    ctx.link_libraries.each do |x, kind|
       link_args << "-l" + x
     end
 

src/savi/compiler/context.cr

@@ -45,7 +45,7 @@ class Savi::Compiler::Context
 
   getter link_c_files = Set(String).new
   getter link_cpp_files = Set(String).new
-  getter link_libraries = Set(String).new
+  getter link_libraries = Hash(String, Symbol).new
   getter link_libraries_by_foreign_function = Hash(String, String).new
 
   getter options : Compiler::Options

src/savi/program/declarator/intrinsic.cr

@@ -94,8 +94,9 @@ module Savi::Program::Intrinsic
           raise NotImplementedError.new(declarator.name.value)
         end
       when "ffi_link_lib"
-        name = terms["name"].as(AST::Identifier)
-        ctx.link_libraries.add(name.value)
+        name = terms["name"].as(AST::Identifier).value
+        ctx.link_libraries[name] = :dynamic
+        scope.current_ffi_link_lib = name
       when "ffi_link_c_files", "ffi_link_cpp_files"
         terms["filenames"].as(AST::Group).terms.each { |term|
           c_file_path =
@@ -118,6 +119,17 @@ module Savi::Program::Intrinsic
         raise NotImplementedError.new(declarator.pretty_inspect)
       end
 
+    # Declarations within an ffi_link_lib declaration.
+    when "ffi_link_lib"
+      case declarator.name.value
+      when "prefer"
+        if terms["static"]?
+          ctx.link_libraries[scope.current_ffi_link_lib] = :prefer_static
+        end
+      else
+        raise NotImplementedError.new(declarator.pretty_inspect)
+      end
+
     # Declarations within a declarator definition.
     when "declarator"
       case declarator.name.value

src/savi/program/declarator/scope.cr

@@ -19,6 +19,8 @@ class Savi::Program::Declarator::Scope
   setter current_declarator : Declarator?
   getter! current_declarator_term : Declarator::TermAcceptor
   setter current_declarator_term : Declarator::TermAcceptor?
+  getter! current_ffi_link_lib : String
+  setter current_ffi_link_lib : String?
   getter! current_type : Type
   setter current_type : Type?
   getter! current_function : Function