From 0f0a44257874478eaacd60a6a9ad446bd7716ef5 Mon Sep 17 00:00:00 2001
From: Mattia Giambirtone <nocturn9x@nocturn9x.space>
Date: Wed, 25 May 2022 14:38:34 +0200
Subject: [PATCH] Fixed issues with stack frames when returning from functions

---
 src/backend/vm.nim        |  2 +-
 src/config.nim            |  2 +-
 src/frontend/compiler.nim |  4 +++-
 src/main.nim              | 26 ++++++++++++++++----------
 src/tests.pn              |  8 ++++----
 5 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/src/backend/vm.nim b/src/backend/vm.nim
index 9c043f3..85a73fc 100644
--- a/src/backend/vm.nim
+++ b/src/backend/vm.nim
@@ -239,7 +239,7 @@ proc dispatch*(self: PeonVM) =
                 # pushing it on the stack
                 let retVal = self.pop()
                 let frame = self.frames.pop()
-                for i in countdown(0, frame):
+                for i in countdown(frame, 1):
                     discard self.pop()
                 self.ip = int(self.pop().uInt)
                 self.push(retVal)
diff --git a/src/config.nim b/src/config.nim
index 1fda235..6014eb9 100644
--- a/src/config.nim
+++ b/src/config.nim
@@ -27,7 +27,7 @@ when len(PEON_COMMIT_HASH) != 40:
 const PEON_BRANCH* = "master"
 when len(PEON_BRANCH) > 255:
     {.fatal: "The git branch name's length must be less than or equal to 255 characters".}
-const DEBUG_TRACE_VM* = false # Traces VM execution
+const DEBUG_TRACE_VM* = true # Traces VM execution
 const DEBUG_TRACE_GC* = false # Traces the garbage collector (TODO)
 const DEBUG_TRACE_ALLOCATION* = false # Traces memory allocation/deallocation
 const DEBUG_TRACE_COMPILER* = false # Traces the compiler
diff --git a/src/frontend/compiler.nim b/src/frontend/compiler.nim
index a08a1e3..4f99823 100644
--- a/src/frontend/compiler.nim
+++ b/src/frontend/compiler.nim
@@ -940,12 +940,14 @@ proc identifier(self: Compiler, node: IdentExpr) =
     else:
         self.detectClosureVariable(s.name)
         let t = self.getStackPos(node)
-        let index = t.pos
+        var index = t.pos
         # We don't check if index is -1 because if it
         # were, self.resolve() would have returned nil
         if not t.closedOver:
             # Static name resolution, loads value at index in the stack. Very fast. Much wow.
             self.emitByte(LoadVar)
+            if self.scopeDepth > 0:
+                inc(index)  # Skip the return address!
             self.emitBytes((index - self.frames[self.scopeDepth]).toTriple())
         else:
             if self.closedOver.len() == 0:
diff --git a/src/main.nim b/src/main.nim
index 916c074..86ac54a 100644
--- a/src/main.nim
+++ b/src/main.nim
@@ -3,6 +3,8 @@ import strformat
 import strutils
 import terminal
 import parseopt
+import nimSHA2
+import times
 import os
 
 # Thanks art <3
@@ -20,6 +22,7 @@ import frontend/parser as p
 import frontend/compiler as c
 import backend/vm as v
 import util/serializer as s
+import util/debugger
 import config
 
 # Forward declarations
@@ -29,17 +32,10 @@ proc getLineEditor: LineEditor
 # Handy dandy compile-time constants
 const debugLexer = false
 const debugParser = false
-const debugCompiler = true
-const debugSerializer = true
+const debugCompiler = false
+const debugSerializer = false
 const debugRuntime = false
-
-when debugSerializer:
-    import nimSHA2
-    import times
-
-when debugCompiler:
-    import util/debugger
-
+    
 
 proc repl =
     styledEcho fgMagenta, "Welcome into the peon REPL!"
@@ -123,6 +119,11 @@ proc repl =
                     styledEcho fgGreen, "OK"
                 else:
                     styledEcho fgRed, "Corrupted"
+                stdout.styledWrite(fgBlue, "\t- CFI segment: ")
+                if serialized.chunk.cfi == compiled.cfi:
+                    styledEcho fgGreen, "OK"
+                else:
+                    styledEcho fgRed, "Corrupted"
             when debugRuntime:
                 styledEcho fgCyan, "\n\nExecution step: "
             vm.run(serialized.chunk)
@@ -240,6 +241,11 @@ proc runFile(f: string) =
                 styledEcho fgGreen, "OK"
             else:
                 styledEcho fgRed, "Corrupted"
+            stdout.styledWrite(fgBlue, "\t- CFI segment: ")
+            if serialized.chunk.cfi == compiled.cfi:
+                styledEcho fgGreen, "OK"
+            else:
+                styledEcho fgRed, "Corrupted"
         when debugRuntime:
             styledEcho fgCyan, "\n\nExecution step: "
         vm.run(serialized.chunk)
diff --git a/src/tests.pn b/src/tests.pn
index a422187..0631a8f 100644
--- a/src/tests.pn
+++ b/src/tests.pn
@@ -6,11 +6,11 @@ operator `+`(a: int32): int32 {
     return a;
 }
 
-fn `+`(a, b: int): int {
-    return a + b;
+fn `+`(a, b: int): int32 {
+    return 0'i32;  # Just to test error messages
 }
 
-var `+`: int = 1;  # hehehehe
+var `+`: int = 1;  # Can't call a value!
 
 +1;  # Works: defined for int64
-# +1'u8; # Nope!
++1'u8; # No implementation for uint8, error!