From 500df014253116ea810332518d3a2868024e3ad3 Mon Sep 17 00:00:00 2001
From: Torsten <torsten@rubydesign.fi>
Date: Wed, 18 Mar 2020 13:10:09 +0200
Subject: [PATCH] rename allocator to standard_allocator

planning to have platform dish it out
---
 lib/risc.rb                          |  2 +-
 lib/risc/allocator.rb                | 64 --------------------------
 lib/risc/callable_compiler.rb        |  1 -
 lib/risc/register_value.rb           |  8 ----
 lib/risc/standard_allocator.rb       | 68 ++++++++++++++++++++++++++++
 test/risc/test_allocator.rb          | 41 -----------------
 test/risc/test_standard_allocator.rb | 45 ++++++++++++++++++
 7 files changed, 114 insertions(+), 115 deletions(-)
 delete mode 100644 lib/risc/allocator.rb
 create mode 100644 lib/risc/standard_allocator.rb
 delete mode 100644 test/risc/test_allocator.rb
 create mode 100644 test/risc/test_standard_allocator.rb

diff --git a/lib/risc.rb b/lib/risc.rb
index 334c2493..e9810ed8 100644
--- a/lib/risc.rb
+++ b/lib/risc.rb
@@ -29,7 +29,7 @@ require_relative "risc/linker"
 require_relative "risc/callable_compiler"
 require_relative "risc/method_compiler"
 require_relative "risc/block_compiler"
-require_relative "risc/allocator"
+require_relative "risc/standard_allocator"
 require_relative "risc/assembler"
 require_relative "risc/risc_collection"
 
diff --git a/lib/risc/allocator.rb b/lib/risc/allocator.rb
deleted file mode 100644
index 5a7e5302..00000000
--- a/lib/risc/allocator.rb
+++ /dev/null
@@ -1,64 +0,0 @@
-module Risc
-  # just moved compilers register related stuff here
-  #
-  # Allocator keeps a list of registers and passes them out
-  # upon request. they must be returned in order
-  class Allocator
-
-    def initialize( compiler , platform)
-      @compiler = compiler
-      @platform = platform
-      @regs = []
-      reset_regs
-    end
-    attr_reader :regs , :compiler , :platform
-
-    def regs_empty?
-      @regs.empty?
-    end
-    def add_reg(reg)
-      raise "not reg #{reg.class}" unless reg.is_a?(RegisterValue)
-      @regs << reg
-    end
-    def pop
-      @regs.pop
-    end
-    def clear_regs
-      @regs.clear
-    end
-
-    # require a (temporary) register. code must give this back with release_reg
-    # Second extra parameter may give extra info about the value, see RegisterValue
-    def use_reg( type , extra = {} )
-      raise "Not type #{type.inspect}:#{type.class}" unless type.is_a?(Symbol) or type.is_a?(Parfait::Type)
-      if @regs.empty?
-        reg = Risc.tmp_reg(type , extra)
-      else
-        reg = @regs.last.next_reg_use(type , extra)
-      end
-      @regs << reg
-      return reg
-    end
-
-    def copy( reg , source )
-      copied = use_reg reg.type
-      add_code Register.transfer( source , reg , copied )
-      copied
-    end
-
-    # releasing a register (accuired by use_reg) makes it available for use again
-    # thus avoiding possibly using too many registers
-    def release_reg( reg )
-      last = @regs.pop
-      raise "released register in wrong order, expect #{last} but was #{reg}" if reg != last
-    end
-
-    # reset the registers to be used. Start at r4 for next usage.
-    # Every statement starts with this, meaning each statement may use all registers, but none
-    # get saved. Statements have affect on objects.
-    def reset_regs
-      @regs.clear
-    end
-
-  end
-end
diff --git a/lib/risc/callable_compiler.rb b/lib/risc/callable_compiler.rb
index f6a4423d..551172bc 100644
--- a/lib/risc/callable_compiler.rb
+++ b/lib/risc/callable_compiler.rb
@@ -155,4 +155,3 @@ module Risc
     end
   end
 end
-require_relative "allocator"
diff --git a/lib/risc/register_value.rb b/lib/risc/register_value.rb
index 8b5800b5..e51a4813 100644
--- a/lib/risc/register_value.rb
+++ b/lib/risc/register_value.rb
@@ -130,14 +130,6 @@ module Risc
       symbol == other.symbol
     end
 
-    #helper method to calculate with register symbols
-    def next_reg_use( type , extra = {} )
-      int = @symbol[1,3].to_i
-      raise "No more registers #{self}" if int > 11
-      sym = "r#{int + 1}".to_sym
-      RegisterValue.new( sym , type, extra)
-    end
-
     def rxf_reference_name
       @symbol
     end
diff --git a/lib/risc/standard_allocator.rb b/lib/risc/standard_allocator.rb
new file mode 100644
index 00000000..156508f2
--- /dev/null
+++ b/lib/risc/standard_allocator.rb
@@ -0,0 +1,68 @@
+module Risc
+  #
+  # StandardAllocator keeps a list of registers whole names it accuires from the
+  # Plaform.
+  #
+  # It allocates registers by going throught the instructions and dishing
+  # out sequential registers.
+  # Before doing that it determines live ranges, so registers can be returned
+  # when not used anymore, and thus reused.
+  class StandardAllocator
+
+    def initialize( compiler , platform)
+      @compiler = compiler
+      @platform = platform
+      @used_regs = {}
+      reset_used_regs
+    end
+    attr_reader :used_regs , :compiler , :platform
+
+    def used_regs_empty?
+      @used_regs.empty?
+    end
+
+    def use_reg(reg)
+      raise "not reg #{reg.class}" unless reg.is_a?(RegisterValue)
+      @used_regs[reg.symbol] = reg
+    end
+
+    #
+    def release_reg(reg)
+      @used_regs.pop
+    end
+
+    def clear_used_regs
+      @used_regs.clear
+    end
+
+    #helper method to calculate with register symbols
+    def next_reg_use( type , extra = {} )
+      int = @symbol[1,3].to_i
+      raise "No more registers #{self}" if int > 11
+      sym = "r#{int + 1}".to_sym
+      RegisterValue.new( sym , type, extra)
+    end
+
+    def copy( reg , source )
+      copied = use_reg reg.type
+      add_code Register.transfer( source , reg , copied )
+      copied
+    end
+
+    # releasing a register (accuired by use_reg) makes it available for use again
+    # thus avoiding possibly using too many registers
+    def release_reg( reg )
+      reg = reg.symbol if reg.is_a?(RegisterValue)
+      raise "not symbol #{reg}:#{reg.class}" unless reg.is_a?(Symbol)
+      @used_regs.delete(reg)
+    end
+
+    # reset the registers to be used. Start at r4 for next usage.
+    # Every statement starts with this, meaning each statement may use all registers, but none
+    # get saved. Statements have affect on objects.
+    def reset_used_regs
+      @used_regs.clear
+    end
+
+  end
+end
diff --git a/test/risc/test_allocator.rb b/test/risc/test_allocator.rb
deleted file mode 100644
index 10cbc912..00000000
--- a/test/risc/test_allocator.rb
+++ /dev/null
@@ -1,41 +0,0 @@
-require_relative "../helper"
-
-module Risc
-  class TestAllocator < MiniTest::Test
-
-    def setup
-      Parfait.boot!(Parfait.default_test_options)
-      @allocator = Allocator.new(Risc.test_compiler , Platform.for(:arm))
-    end
-    def tmp_reg
-      Risc.tmp_reg(:Type)
-    end
-    def test_regs
-      assert_equal Array , @allocator.regs.class
-    end
-    def test_empty
-      assert @allocator.regs_empty?
-    end
-    def test_compiler
-      assert_equal CallableCompiler , @allocator.compiler.class
-      assert_equal :fake_name , @allocator.compiler.callable.name
-    end
-    def test_platform
-      assert_equal Arm::ArmPlatform , @allocator.platform.class
-    end
-    def test_add_ok
-      assert_equal Array, @allocator.add_reg(tmp_reg).class
-    end
-    def test_add_fail
-      assert_raises{ @allocator.add_reg(1)}
-    end
-    def test_pop
-      @allocator.add_reg(tmp_reg)
-      assert_equal RegisterValue , @allocator.pop.class
-    end
-    def test_clear
-      @allocator.clear_regs
-      assert @allocator.regs_empty?
-    end
-  end
-end
diff --git a/test/risc/test_standard_allocator.rb b/test/risc/test_standard_allocator.rb
new file mode 100644
index 00000000..abcf0861
--- /dev/null
+++ b/test/risc/test_standard_allocator.rb
@@ -0,0 +1,45 @@
+require_relative "../helper"
+
+module Risc
+  class TestStandardAllocator < MiniTest::Test
+
+    def setup
+      Parfait.boot!(Parfait.default_test_options)
+      @allocator = StandardAllocator.new(Risc.test_compiler , Platform.for(:arm))
+    end
+    def tmp_reg
+      Risc.tmp_reg(:Type)
+    end
+    def test_regs
+      assert_equal Hash , @allocator.used_regs.class
+    end
+    def test_empty
+      assert @allocator.used_regs_empty?
+    end
+    def test_compiler
+      assert_equal CallableCompiler , @allocator.compiler.class
+      assert_equal :fake_name , @allocator.compiler.callable.name
+    end
+    def test_platform
+      assert_equal Arm::ArmPlatform , @allocator.platform.class
+    end
+    def test_add_ok
+      assert_equal RegisterValue, @allocator.use_reg(tmp_reg).class
+    end
+    def test_add_fail
+      assert_raises{ @allocator.use_reg(1)}
+    end
+    def test_release_reg
+      @allocator.use_reg(tmp_reg)
+      assert_equal RegisterValue , @allocator.release_reg(tmp_reg).class
+    end
+    def test_remove_symbol
+      @allocator.use_reg(tmp_reg)
+      assert_equal RegisterValue , @allocator.release_reg(tmp_reg.symbol).class
+    end
+    def test_clear
+      @allocator.clear_used_regs
+      assert @allocator.used_regs_empty?
+    end
+  end
+end