From 4efda21007aed3f91e9360aaa1cea93975abd994 Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Sun, 1 Dec 2024 11:17:14 +0100
Subject: [PATCH] Add array assignment to the IR

---
 TODO                                      |  6 ----
 lib/Language/Elna/Backend/Allocator.hs    |  4 +++
 lib/Language/Elna/Backend/Intermediate.hs |  4 +--
 lib/Language/Elna/RiscV/CodeGenerator.hs  | 36 +++++++++++++++++++++++
 4 files changed, 42 insertions(+), 8 deletions(-)

diff --git a/TODO b/TODO
index 1fa05f5..964de44 100644
--- a/TODO
+++ b/TODO
@@ -1,9 +1,3 @@
-# Intermediate code generation
-
-- To access named parameters inside a procedure, IR should be able to reference
-  them. During the generation the needed information (e.g. offsets or registers)
-  can be extracted from the symbol table and saved in the operands.
-
 # ELF generation
 
 - Don't ignore relocations where the symbol is not defined in the symbol table.
diff --git a/lib/Language/Elna/Backend/Allocator.hs b/lib/Language/Elna/Backend/Allocator.hs
index f0f285b..acdf3e5 100644
--- a/lib/Language/Elna/Backend/Allocator.hs
+++ b/lib/Language/Elna/Backend/Allocator.hs
@@ -135,6 +135,10 @@ quadruple = \case
     AssignQuadruple operand1 variable -> do
         operand1' <- operand operand1
         AssignQuadruple operand1' <$> storeVariable variable
+    ArrayAssignQuadruple operand1 operand2 variable -> do
+        operand1' <- operand operand1
+        operand2' <- operand operand2
+        ArrayAssignQuadruple operand1' operand2' <$> storeVariable variable
 
 operand :: Operand Variable -> Allocator r (Operand (Store r))
 operand (IntOperand x) = pure $ IntOperand x
diff --git a/lib/Language/Elna/Backend/Intermediate.hs b/lib/Language/Elna/Backend/Intermediate.hs
index 331d044..dcf0ede 100644
--- a/lib/Language/Elna/Backend/Intermediate.hs
+++ b/lib/Language/Elna/Backend/Intermediate.hs
@@ -50,8 +50,8 @@ data Quadruple v
     | DivisionQuadruple (Operand v) (Operand v) v
     | GoToQuadruple Label
     | AssignQuadruple (Operand v) v
-    {-| ArrayQuadruple Variable Operand Variable
-    | ArrayAssignQuadruple Operand Operand Variable -}
+    {-| ArrayQuadruple Variable Operand Variable -}
+    | ArrayAssignQuadruple (Operand v) (Operand v) v
     | LessOrEqualQuadruple (Operand v) (Operand v) Label
     | GreaterOrEqualQuadruple (Operand v) (Operand v) Label
     | GreaterQuadruple (Operand v) (Operand v) Label
diff --git a/lib/Language/Elna/RiscV/CodeGenerator.hs b/lib/Language/Elna/RiscV/CodeGenerator.hs
index a0ad5f9..6e7a8cd 100644
--- a/lib/Language/Elna/RiscV/CodeGenerator.hs
+++ b/lib/Language/Elna/RiscV/CodeGenerator.hs
@@ -259,6 +259,42 @@ quadruple _ (AssignQuadruple operand1 store)
                 $ RiscV.BaseInstruction RiscV.OpImm
                 $ RiscV.I storeRegister RiscV.ADDI operandRegister1 0
          in pure $ statements1 <> Vector.cons instruction storeStatements 
+quadruple _ (ArrayAssignQuadruple assigneeOperand indexOperand store)
+    | IntOperand immediateAssigneeOperand <- assigneeOperand =
+        let (storeRegister, storeStatements) = storeWithOffset store indexOperand
+         in pure $ lui immediateAssigneeOperand storeRegister <> storeStatements
+    | VariableOperand variableAssigneeOperand <- assigneeOperand =
+        let (assigneeOperandRegister, assigneeStatements) = loadFromStore variableAssigneeOperand
+            (storeRegister, storeStatements) = storeWithOffset store indexOperand
+            instruction = Instruction
+                $ RiscV.BaseInstruction RiscV.OpImm
+                $ RiscV.I storeRegister RiscV.ADDI assigneeOperandRegister 0
+         in pure $ assigneeStatements <> Vector.cons instruction storeStatements 
+  where
+    storeWithOffset :: RiscVStore -> Operand RiscVStore -> (RiscV.XRegister, Vector Statement)
+    storeWithOffset (RegisterStore register) _ = (register, mempty)
+    storeWithOffset (StackStore offset register) (IntOperand indexOffset) =
+        let storeInstruction = Instruction
+                $ RiscV.BaseInstruction RiscV.Store
+                $ RiscV.S (fromIntegral $ offset + indexOffset) RiscV.SW RiscV.S0 register
+        in (register, Vector.singleton storeInstruction)
+    storeWithOffset (StackStore offset register) (VariableOperand indexOffset) =
+        let baseRegisterInstruction = Instruction
+                $ RiscV.BaseInstruction RiscV.OpImm
+                $ RiscV.I immediateRegister RiscV.ADDI RiscV.S0 0
+            (indexRegister, indexStatements) = loadFromStore indexOffset
+            registerWithOffset = Instruction
+                $ RiscV.BaseInstruction RiscV.OpImm
+                $ RiscV.I immediateRegister RiscV.ADDI indexRegister 0
+            storeInstruction = Instruction
+                $ RiscV.BaseInstruction RiscV.Store
+                $ RiscV.S (fromIntegral offset) RiscV.SW immediateRegister register
+            statements = Vector.fromList
+                [ baseRegisterInstruction
+                , registerWithOffset
+                , storeInstruction
+                ]
+        in (register, indexStatements <> statements)
 
 unconditionalJal :: Label -> Statement
 unconditionalJal (Label goToLabel) = Instruction