From cac4c1eb1e509bbee274a1ea0dc2b309d6403a92 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Mon, 16 Sep 2024 21:49:20 +0200
Subject: [PATCH] improve callgraph unused subroutine check for routines called
 from inline asm

---
 compilerAst/src/prog8/compiler/CallGraph.kt | 21 ++++++++++++----
 docs/source/todo.rst                        |  4 ---
 examples/cx16/kefrenbars.p8                 |  8 ++++--
 examples/test.p8                            | 28 +++++++++++++--------
 4 files changed, 40 insertions(+), 21 deletions(-)

diff --git a/compilerAst/src/prog8/compiler/CallGraph.kt b/compilerAst/src/prog8/compiler/CallGraph.kt
index 28218be75..8b5ec582d 100644
--- a/compilerAst/src/prog8/compiler/CallGraph.kt
+++ b/compilerAst/src/prog8/compiler/CallGraph.kt
@@ -160,11 +160,22 @@ class CallGraph(private val program: Program) : IAstVisitor {
     fun unused(module: Module) = module !in usedModules
 
     fun unused(sub: Subroutine): Boolean {
-        return sub !in usedSubroutines && !nameInAssemblyCode(sub.name, listOf("p8s_", ""))
+        if(sub in usedSubroutines)
+            return false
+        val asm = nameInAssemblyCode(sub.name, listOf("p8s_", ""))
+        if(asm!=null) {
+            // check that the asm block that calls us, is inside a subroutine that is unused or not
+            val containingSub = asm.definingSubroutine
+            return if(containingSub != null && containingSub !== sub)
+                unused(containingSub)
+            else
+                false
+        }
+        return true
     }
 
     fun unused(block: Block): Boolean {
-        return block !in usedBlocks && !nameInAssemblyCode(block.name, listOf("p8b_", ""))
+        return block !in usedBlocks && nameInAssemblyCode(block.name, listOf("p8b_", ""))==null
     }
 
     fun unused(decl: VarDecl): Boolean {
@@ -187,13 +198,13 @@ class CallGraph(private val program: Program) : IAstVisitor {
     }
 
     private val prefixes = listOf("p8b_", "p8v_", "p8s_", "p8c_", "p8l_", "p8_", "")
-    private fun nameInAssemblyCode(name: String, knownAsmPrefixes: List<String> = emptyList()): Boolean {
+    private fun nameInAssemblyCode(name: String, knownAsmPrefixes: List<String> = emptyList()): InlineAssembly? {
         if(knownAsmPrefixes.isNotEmpty())
-            return allAssemblyNodes.any {
+            return allAssemblyNodes.firstOrNull {
                 knownAsmPrefixes.any { prefix -> prefix+name in it.names }
             }
 
-        return allAssemblyNodes.any {
+        return allAssemblyNodes.firstOrNull {
             prefixes.any { prefix -> prefix+name in it.names }
         }
     }
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index ce1024254..fb5d3198b 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -1,10 +1,6 @@
 TODO
 ====
 
-callgraph issue? : if a sub contains another sub and it calls that, the outer sub is never removed even if it doesn't get called?
-(diskio, when read4hex is placed back inside internal_f_tell() )
-
-
 Improve register load order in subroutine call args assignments:
 in certain situations, the "wrong" order of evaluation of function call arguments is done which results
 in overwriting registers that already got their value, which requires a lot of stack juggling (especially on plain 6502 cpu!)
diff --git a/examples/cx16/kefrenbars.p8 b/examples/cx16/kefrenbars.p8
index 903005ffd..26bee4a3e 100644
--- a/examples/cx16/kefrenbars.p8
+++ b/examples/cx16/kefrenbars.p8
@@ -35,7 +35,7 @@ main {
 
 
 irq {
-    const ubyte BAR_Y_OFFSET = 6
+    const ubyte BAR_Y_OFFSET = 5
     uword next_irq_line = 0
     ubyte anim1 = 0
     ubyte av1 = 0
@@ -47,7 +47,7 @@ irq {
         next_irq_line += BAR_Y_OFFSET
         anim1 += 7
         anim2 += 4
-        if next_irq_line > 480-BAR_Y_OFFSET {
+        if next_irq_line > 480 {
             av1++
             av2 += 2
             anim1 = av1
@@ -55,6 +55,10 @@ irq {
             next_irq_line = 0
             ; erase the bars
             gfx2.horizontal_line(0, 0, 320, 3)
+;            gfx2.position(0, 0)
+;            repeat 10 {
+;                gfx2.next_pixels(pixels, len(pixels))
+;            }
         } else {
             ; add new bar on top
             gfx2.position(math.sin8u(anim1)/2 + math.cos8u(anim2)/2 + $0010, 0)
diff --git a/examples/test.p8 b/examples/test.p8
index aeb1f29ce..57a1f5728 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -1,19 +1,27 @@
-%import monogfx
 %option no_sysinit
 %zeropage basicsafe
 
 main {
     sub start() {
-        monogfx.hires()
-        monogfx.circle(320, 240, 200, true)
-        sys.wait(60)
-        monogfx.drawmode(monogfx.MODE_STIPPLE)
-        monogfx.disc(320, 240, 200, true)
-        sys.wait(60)
-        monogfx.drawmode(monogfx.MODE_NORMAL)
-        monogfx.safe_disc(320, 240, 200, true)
+        ; nothing!
+    }
+}
 
-        repeat {
+
+derp {
+    asmsub f_tell() -> uword @R0, uword @R1, uword @R2, uword @R3 {
+        %asm {{
+            jmp  p8s_internal_f_tell
+        }}
+    }
+
+    sub internal_f_tell() {
+        cx16.r1 = read4hex()
+
+        sub read4hex() -> uword {
+            str @shared hex = "0000000000000000000000000000000000000000000"
+            cx16.r0++
+            return cx16.r0
         }
     }
 }