diff --git a/build_tests/build_tests.rb b/build_tests/build_tests.rb
index eaa34c5..1961105 100644
--- a/build_tests/build_tests.rb
+++ b/build_tests/build_tests.rb
@@ -726,7 +726,7 @@ test 'supports build hooks to override the entire vars hash' do
   result = run_rscons(args: %w[-f build_hooks_override_vars.rb])
   expect_eq(result.stderr, "")
   verify_lines(lines(result.stdout), [
-    %r{gcc -c -o one.o -MMD -MF build/o/one.o.mf -Isrc -Isrc/one -Isrc/two -O1 src/two/two.c},
+    %r{gcc -c -o one.o -MMD -MF build/o/one.o.mf -Isrc -Isrc/one -Isrc/two -O1 src/one/one.c},
     %r{gcc -c -o two.o -MMD -MF build/o/two.o.mf -Isrc -Isrc/one -Isrc/two -O2 src/two/two.c},
   ])
   expect_truthy(File.exist?('one.o'))
@@ -3557,4 +3557,12 @@ test "supports a Barrier builder to order builds" do
   expect_match(slines[2], /B:one/)
 end
 
+test "maps relative paths to absolute paths for dependency resolution" do
+  test_dir "simple"
+  result = run_rscons(args: %w[-f abs_rel_paths.rb])
+  expect_eq(result.stderr, "")
+  expect_eq(result.status, 0)
+  expect_match(result.stdout, /three.*two.*one/m)
+end
+
 run_tests
diff --git a/build_tests/simple/abs_rel_paths.rb b/build_tests/simple/abs_rel_paths.rb
new file mode 100644
index 0000000..fd1c721
--- /dev/null
+++ b/build_tests/simple/abs_rel_paths.rb
@@ -0,0 +1,14 @@
+class B < Builder
+  def run(*args)
+    puts @target
+    true
+  end
+end
+
+env do |env|
+  env.add_builder(B)
+  env.B("one", File.expand_path("two"))
+  env.B("two")
+  env.B("three")
+  env.depends("two", File.expand_path("three"))
+end
diff --git a/build_tests/typical/build_hooks_override_vars.rb b/build_tests/typical/build_hooks_override_vars.rb
index d6810c3..6b46ce2 100644
--- a/build_tests/typical/build_hooks_override_vars.rb
+++ b/build_tests/typical/build_hooks_override_vars.rb
@@ -3,7 +3,6 @@ env(echo: :command) do |env|
   env.add_build_hook do |builder|
     if builder.name == "Object" && builder.sources.first =~ %r{one\.c}
       builder.vars["CFLAGS"] << "-O1"
-      builder.sources = ['src/two/two.c']
     elsif builder.name == "Object" && builder.target =~ %r{two\.o}
       new_vars = builder.vars.clone
       new_vars["CFLAGS"] << "-O2"
diff --git a/lib/rscons/builder.rb b/lib/rscons/builder.rb
index fa844dd..6b66851 100644
--- a/lib/rscons/builder.rb
+++ b/lib/rscons/builder.rb
@@ -29,19 +29,27 @@ module Rscons
 
     # @return [String, Symbol]
     #   Target file name.
-    attr_accessor :target
+    attr_reader :target
 
-    # @return [Array<String>]
-    #   Source file name(s).
-    attr_accessor :sources
+    # @return [String, Symbol]
+    #   Absolute target file name.
+    attr_reader :abstarget
+
+    # @return [Array<String, Symbol>]
+    #   Source file names.
+    attr_reader :sources
+
+    # @return [Array<String, Symbol>]
+    #   Absolute source file names.
+    attr_reader :abssources
 
     # @return [Cache]
     #   Cache instance.
-    attr_accessor :cache
+    attr_reader :cache
 
     # @return [Environment]
     #   The {Environment} performing the build operation.
-    attr_accessor :env
+    attr_reader :env
 
     # @return [Hash, VarSet]
     #   Construction variables used to perform the build operation.
@@ -49,7 +57,7 @@ module Rscons
 
     # @return [Set<String>]
     #   Side effect file(s) produced when this builder runs.
-    attr_accessor :side_effects
+    attr_reader :side_effects
 
     # @return [Integer]
     #   Build step.
@@ -71,7 +79,11 @@ module Rscons
     #   Extra construction variables.
     def initialize(options)
       @target = options[:target]
-      @sources = options[:sources]
+      @abstarget = Util.absolute_path(@target)
+      @sources = Array(options[:sources])
+      @abssources = @sources.map do |source|
+        Util.absolute_path(source)
+      end
       @cache = options[:cache]
       @env = options[:env]
       @vars = options[:vars]
@@ -103,7 +115,7 @@ module Rscons
     # @return [void]
     def produces(*side_effects)
       side_effects.each do |side_effect|
-        side_effect_expanded = @env.expand(side_effect)
+        side_effect_expanded = Util.absolute_path(@env.expand(side_effect))
         @env.register_side_effect(side_effect_expanded)
         @side_effects << side_effect_expanded
       end
diff --git a/lib/rscons/builder_set.rb b/lib/rscons/builder_set.rb
index f0bae36..bec7449 100644
--- a/lib/rscons/builder_set.rb
+++ b/lib/rscons/builder_set.rb
@@ -27,8 +27,8 @@ module Rscons
       #   env.Directory("dest")
       #   env.Install("dest", "bin")
       #   env.Install("dest", "share")
-      self[builder.target] ||= []
-      self[builder.target] << builder
+      self[builder.abstarget] ||= []
+      self[builder.abstarget] << builder
     end
 
     # Return the number of remaining build steps.
@@ -54,7 +54,7 @@ module Rscons
     #   The next builder to run.
     def get_next_builder_to_run(targets_still_building)
       to_build = self.find do |target, builders|
-        deps = builders.first.sources + (@build_dependencies[target] || []).to_a
+        deps = builders.first.abssources + (@build_dependencies[target] || []).to_a
         # All dependencies must have been built for this target to be ready to
         # build.
         deps.all? do |dep|
@@ -79,7 +79,7 @@ module Rscons
       # not find a builder to run above, then there might be a circular
       # dependency introduced by the user.
       if (self.size > 0) and targets_still_building.empty?
-        raise "Could not find a runnable builder. Possible circular dependency for #{self.keys.first}"
+        raise "Could not find a runnable builder. Possible circular dependency for #{self.first[1].first.target}"
       end
     end
 
diff --git a/lib/rscons/environment.rb b/lib/rscons/environment.rb
index ebaaba6..538cb03 100644
--- a/lib/rscons/environment.rb
+++ b/lib/rscons/environment.rb
@@ -371,8 +371,8 @@ module Rscons
           @builder_sets << build_builder_set
         end
         @builder_sets.last << builder
-        @build_steps += 1
-        @build_targets[target] = builder
+        @build_steps += 1 unless builder.is_a?(Rscons::Builders::Barrier)
+        @build_targets[builder.abstarget] = builder
         builder
       else
         super
@@ -396,8 +396,10 @@ module Rscons
         end
         expand(ud)
       end
+      target = Util.absolute_path(target)
       @user_deps[target] ||= []
-      (@user_deps[target] + user_deps).each do |ud|
+      user_deps.map! {|ud| Util.absolute_path(ud)}
+      user_deps.each do |ud|
         unless Rscons.phony_target?(ud) || @user_deps[target].include?(ud)
           @user_deps[target] << ud
         end
@@ -432,13 +434,13 @@ module Rscons
       targets = Array(targets)
       prerequisites = Array(prerequisites)
       targets.each do |target|
-        target = expand(target)
+        target = Util.absolute_path(expand(target))
         @registered_build_dependencies[target] ||= Set.new
         prerequisites.each do |prerequisite|
           if prerequisite.is_a?(Builder)
             prerequisite = prerequisite.target
           end
-          prerequisite = expand(prerequisite)
+          prerequisite = Util.absolute_path(expand(prerequisite))
           @registered_build_dependencies[target] << prerequisite
         end
       end
@@ -454,9 +456,9 @@ module Rscons
     #
     # @return [void]
     def produces(target, *side_effects)
-      target = expand(target)
+      abstarget = Util.absolute_path(expand(target))
       @builder_sets.reverse.each do |builder_set|
-        if builders = builder_set[target]
+        if builders = builder_set[abstarget]
           builders.last.produces(*side_effects)
           return
         end
@@ -473,7 +475,7 @@ module Rscons
     # @param side_effect [String]
     #   Side effect fiel name.
     def register_side_effect(side_effect)
-      @side_effects << side_effect
+      @side_effects << Util.absolute_path(side_effect)
     end
 
     # Return the list of user dependencies for a given target.
@@ -484,6 +486,7 @@ module Rscons
     #   List of user-specified dependencies for the target, or nil if none were
     #   specified.
     def get_user_deps(target)
+      target = Util.absolute_path(target)
       @user_deps[target]
     end
 
@@ -507,10 +510,11 @@ module Rscons
     # @return [String]
     #   Output file name.
     def register_dependency_build(target, source, suffix, vars, builder_class)
+      target = Util.absolute_path(target)
       output_fname = get_build_fname(source, suffix, builder_class)
       self.__send__(builder_class.name, output_fname, source, vars)
       @registered_build_dependencies[target] ||= Set.new
-      @registered_build_dependencies[target] << output_fname
+      @registered_build_dependencies[target] << Util.absolute_path(output_fname)
       output_fname
     end
 
@@ -587,6 +591,7 @@ module Rscons
     # @return [Builder, nil]
     #   The {Builder} for target, or +nil+ if none found.
     def builder_for(target)
+      target = Util.absolute_path(target)
       @build_targets[target]
     end
 
@@ -730,7 +735,7 @@ module Rscons
       # If no builder was found to run yet and there are threads available, try
       # to get a runnable builder from the builder set.
       targets_still_building = @threads.reduce([]) do |result, (thread, obj)|
-        result << builder_for_thread(thread).target
+        result << builder_for_thread(thread).abstarget
       end
       if @builder_sets.size > 0
         if builder = @builder_sets[0].get_next_builder_to_run(targets_still_building)
diff --git a/lib/rscons/util.rb b/lib/rscons/util.rb
index 20c4434..8bacb73 100644
--- a/lib/rscons/util.rb
+++ b/lib/rscons/util.rb
@@ -18,15 +18,16 @@ module Rscons
 
       # Return the absolute path for a given target if not a phony target.
       #
-      # @param path [String, Symbol]
+      # @param path [String, Symbol, nil]
       #   Given target name.
       #
-      # @return Absolute path of given target.
+      # @return [String, Symbol, nil]
+      #   Absolute path of given target.
       def absolute_path(path)
-        if Rscons.phony_target?(path)
-          path
-        else
+        if path.is_a?(String)
           File.expand_path(path)
+        else
+          path
         end
       end
 
diff --git a/spec/rscons/environment_spec.rb b/spec/rscons/environment_spec.rb
index e6feb14..0aa7545 100644
--- a/spec/rscons/environment_spec.rb
+++ b/spec/rscons/environment_spec.rb
@@ -138,27 +138,6 @@ module Rscons
       end
     end
 
-    describe "#depends" do
-      it "records the given dependencies in @user_deps" do
-        env = Environment.new
-        env.depends("foo", "bar", "baz")
-        expect(env.instance_variable_get(:@user_deps)).to eq({"foo" => ["bar", "baz"]})
-      end
-      it "records user dependencies only once" do
-        env = Environment.new
-        env.instance_variable_set(:@user_deps, {"foo" => ["bar"]})
-        env.depends("foo", "bar", "baz")
-        expect(env.instance_variable_get(:@user_deps)).to eq({"foo" => ["bar", "baz"]})
-      end
-      it "expands arguments for construction variable references" do
-        env = Environment.new
-        env["foo"] = "foo.exe"
-        env["bar"] = "bar.c"
-        env.depends("${foo}", "${bar}", "a.h")
-        expect(env.instance_variable_get(:@user_deps)).to eq({"foo.exe" => ["bar.c", "a.h"]})
-      end
-    end
-
     describe "#shell" do
       it "executes the given shell command and returns the results" do
         env = Environment.new