From 6b60f721c4be97e0a79e1b16028a5d180eb0ba1e Mon Sep 17 00:00:00 2001
From: Luke Lau <luke_lau@icloud.com>
Date: Tue, 30 Jul 2019 23:26:41 +0100
Subject: [PATCH] Make base pointer to point to the previous frames base
 pointer

Backtrace still looks kinda funny in lldb
---
 codegen.scm | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/codegen.scm b/codegen.scm
index 941dc15..52df26e 100644
--- a/codegen.scm
+++ b/codegen.scm
@@ -167,16 +167,16 @@
     (emit "## storing captives")
 					; store the captured vars
     (for-each
-     (lambda (var-name new-offset)
-       (let ([orig-offset (cdr (assoc var-name env))])
+     (lambda (var-name heap-offset)
+       (let ([stack-offset (cdr (assoc var-name env))])
 	 (emit "### captive ~a" var-name)
-	 (if (eqv? orig-offset 'self-captive)
+	 (if (eqv? stack-offset 'self-captive)
 					; captive refers to this closure:
 					; move heap addr of this closure to stack! 
-	     (emit "movq %rax, ~a(%rax)" new-offset)
+	     (emit "movq %rax, ~a(%rax)" heap-offset)
 	     (begin
-	       (emit "movq ~a(%rbp), %rbx" orig-offset)
-	       (emit "movq %rbx, ~a(%rax)" new-offset)))))
+	       (emit "movq ~a(%rbp), %rbx" stack-offset)
+	       (emit "movq %rbx, ~a(%rax)" heap-offset)))))
      captured
      heap-offsets)))
 
@@ -240,7 +240,7 @@
 	 (params (append captives args))
 
 	 (stack-offsets (map (lambda (i)
-			       (* (- wordsize) i))
+			       (* (- wordsize) (+ 1 i)))
 			     (range 0 (length params))))
 
 	 (env (map cons params stack-offsets)))
@@ -259,7 +259,6 @@
     (emit "push %rbp") ; preserve caller's base pointer
     
     (emit "movq %rsp, %rbp") ; set up our own base pointer
-    (emit "subq $8, %rbp")   
 
 					; load the captured vars onto the stack
     (for-each
@@ -267,7 +266,7 @@
        (begin
 	 (emit "# loading captive ~a" (list-ref captives i))
 	 (emit "movq ~a(~a), %rbx" (* wordsize i) (param-register 0))
-	 (emit "movq %rbx, ~a(%rbp)" (* (- wordsize) i))))
+	 (emit "movq %rbx, ~a(%rbp)" (* (- wordsize) (+ 1 i)))))
      (range 0 (length captives)))
 
 					; load the args onto the stack
@@ -277,7 +276,7 @@
 	 (emit "movq ~a, %rbx" (param-register (+ 1 i)))
 	 (emit "movq %rbx, ~a(%rbp)"
 	       (* (- wordsize)
-		  (+ (length captives) i)))))
+		  (+ 1 (length captives) i)))))
      (range 0 (length args)))
     
     (codegen-expr body (* (- wordsize) (+ 1 (length params))) env)
@@ -541,7 +540,8 @@
     (initialize-heap)
 
     (emit "movq %rsp, %rbp")            ; set up the base pointer
-    (codegen-expr xform-prog 0 '())
+    
+    (codegen-expr xform-prog wordsize '())
 
 					; exit syscall
     (emit "mov %rax, %rdi")
-- 
2.30.2