Merge pull request #3 from V0ldek/code-generation

Fixed redundant local saves.

ChangeLog.md

@@ -9,4 +9,8 @@
 - Added the intermediate representation language, Espresso, with its own lexer and parser.
 - Added IR generation.
 - Added Control Flow Graph and variable liveness analysis.
-- Added x86_64 assembler code generation for the core of the language.
+- Added x86_64 assembler code generation for the core of the language.
+
+## 0.9.1
+
+- Fixed an issue where locals were unnecessarily moved out of stack and back again at end of a basic block when they were not alived in the preceding block.

README.md

@@ -1,4 +1,4 @@
-# Latte v0.9
+# Latte v0.9.1
 
 Compiler of the [Latte programming language](https://www.mimuw.edu.pl/~ben/Zajecia/Mrj2020/Latte/description.html) written in Haskell.
 

package.yaml

@@ -1,5 +1,5 @@
 name:                Latte
-version:             0.9.0.0
+version:             0.9.1.0
 github:              "githubuser/Latte"
 license:             MIT
 author:              "Mateusz Gienieczko"

src/Compiler.hs

@@ -77,7 +77,7 @@ run opt = do
     genStep opt (espressoWithLivenessFile directory fileName) espressoWithLiveness
     printStringV v "Generating x86_64 assembly..."
     let assembly = generate cfgsWithLiveness
-    genOutput opt (unoptAssemblyFile directory fileName) assembly
+    genStep opt (unoptAssemblyFile directory fileName) assembly
     let optAssembly = unlines $ Peephole.optimise (lines assembly)
     genOutput opt (assemblyFile directory fileName) optAssembly
 

src/X86_64/CodeGen/Generator.hs

@@ -354,16 +354,21 @@ resetStack = do
     Emit.decrStack n
     setStack s'
 
+-- Set stack and descriptions to a state where all locals are saved on stack
+-- and nothing else is stored anywhere.
 endBlock :: GenM ()
 endBlock = do
-    locals <- gets (stackReservedSlots . stack)
+    s <- gets stack
+    let locals = stackReservedSlots s
     varSs <- gets vars
     let varSs' = Map.mapWithKey (\vi slot -> VarS {
                 varName = vi,
                 varType = varType $ varSs Map.! vi,
                 varLocs = [slotToLoc slot],
                 varAliases = [vi]}) locals
+        s'     = foldr (\vi x -> snd $ stackInsertReserved vi x) s (Map.keys locals)
     modify (\st -> st {allCode = bbCode st ++ allCode st,
                        bbCode = [],
                        regs = initialRegs,
+                       stack = s',
                        vars = varSs'})