From ff46129c4e0ce25db9b579cec94534d81e909c98 Mon Sep 17 00:00:00 2001
From: Karol Stasiak <karol.m.stasiak@gmail.com>
Date: Tue, 22 Oct 2019 01:39:11 +0200
Subject: [PATCH] #11 Fix allocation of variables in functions with trampolines

---
 src/main/scala/millfork/env/Environment.scala |   5 +
 src/main/scala/millfork/node/CallGraph.scala  |   6 +
 .../scala/millfork/test/Issue11Test.scala     | 108 ++++++++++++++++++
 3 files changed, 119 insertions(+)
 create mode 100644 src/test/scala/millfork/test/Issue11Test.scala

diff --git a/src/main/scala/millfork/env/Environment.scala b/src/main/scala/millfork/env/Environment.scala
index f59ba0e1..33706974 100644
--- a/src/main/scala/millfork/env/Environment.scala
+++ b/src/main/scala/millfork/env/Environment.scala
@@ -119,6 +119,10 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
     if (forZpOnly && !options.platform.hasZeroPage) {
       return
     }
+    if (nf.exists(_.name.endsWith(".trampoline"))) {
+      return
+    }
+    if (log.traceEnabled) log.trace("Allocating variables in " + nf.map(f => "function " + f.name).getOrElse("global scope"))
     val b = get[Type]("byte")
     val p = get[Type]("pointer")
     val params = nf.fold(List[String]()) { f =>
@@ -146,6 +150,7 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
     } else 3
     val toAdd = things.values.flatMap {
       case m: UninitializedMemory if passForAlloc(m.alloc) == pass && nf.isDefined == isLocalVariableName(m.name) && !m.name.endsWith(".addr") && maybeGet[Thing](m.name + ".array").isEmpty =>
+        if (log.traceEnabled) log.trace("Allocating " + m.name)
         val vertex = if (options.flag(CompilationFlag.VariableOverlap)) {
           nf.fold[VariableVertex](GlobalVertex) { f =>
             if (m.alloc == VariableAllocationMethod.Static) {
diff --git a/src/main/scala/millfork/node/CallGraph.scala b/src/main/scala/millfork/node/CallGraph.scala
index ad137dd9..24823fd1 100644
--- a/src/main/scala/millfork/node/CallGraph.scala
+++ b/src/main/scala/millfork/node/CallGraph.scala
@@ -182,6 +182,12 @@ class StandardCallGraph(program: Program, log: Logger) extends CallGraph(program
     if (multiaccessibleFunctions(a.function) || multiaccessibleFunctions(b.function)) {
       return false
     }
+    if (a.function + ".trampoline" == b.function) {
+      return false
+    }
+    if (a.function == b.function + ".trampoline") {
+      return false
+    }
     if (callEdges(a.function -> b.function) || callEdges(b.function -> a.function)) {
       return false
     }
diff --git a/src/test/scala/millfork/test/Issue11Test.scala b/src/test/scala/millfork/test/Issue11Test.scala
new file mode 100644
index 00000000..1e1a9102
--- /dev/null
+++ b/src/test/scala/millfork/test/Issue11Test.scala
@@ -0,0 +1,108 @@
+package millfork.test
+
+import millfork.Cpu
+import millfork.test.emu.{EmuCrossPlatformBenchmarkRun, EmuUnoptimizedCmosRun}
+import org.scalatest.{FunSuite, Matchers}
+
+/**
+  * @author Karol Stasiak
+  */
+class Issue11Test extends FunSuite with Matchers {
+
+  test("Test issue 11") {
+    val src =
+      """
+        |import c64_basic
+        |import stdio
+        |
+        |struct Box {
+        |    byte x,
+        |    byte y,
+        |    byte width,
+        |    byte height
+        |}
+        |
+        |struct Phys_Obj {
+        |    Box pos,
+        |    byte xfrac,
+        |    byte yfrac,
+        |    sbyte xvel,
+        |    sbyte yvel,
+        |    byte xaccel,
+        |    byte yaccel,
+        |    byte xspeed,
+        |    bool on_ground,
+        |    bool jumping,
+        |    bool can_jump
+        |}
+        |
+        |Phys_Obj player1
+        |byte output @$c000
+        |
+        |inline pointer get_metatile_column(word metatiles_column) {
+        |    //This is the function where the original player pointer
+        |    //gets corrupted.
+        |    return pointer(metatiles_column)
+        |}
+        |
+        |byte get_tile(byte column, byte row) {
+        |    byte tile
+        |    pointer metatiles_column
+        |
+        |    metatiles_column = get_metatile_column($0000)
+        |    tile = $00
+        |    return tile
+        |}
+        |
+        |void check_background_collis(byte screenx, byte screeny, byte spritewidth, byte spriteheight) {
+        |    byte new_column1
+        |    byte new_column2
+        |    byte new_row1
+        |    byte new_row2
+        |    byte i
+        |    byte limit
+        |    byte current_tile
+        |
+        |    current_tile = get_tile(0,0)
+        |}
+        |
+        |void check_player_collis_and_update_player_loc(pointer.Phys_Obj player) {
+        |    sbyte temp_vel
+        |    byte old_playerx
+        |    byte old_playerx_frac
+        |    byte old_playery
+        |    byte old_playery_frac
+        |
+        |    old_playerx = player1.pos.x
+        |    old_playery = player1.pos.y
+        |    old_playerx_frac = player1.xfrac
+        |    old_playery_frac = player1.yfrac
+        |
+        |    check_background_collis(player1.pos.x, player1.pos.y, player1.pos.width, player1.pos.height)
+        |}
+        |
+        |inline void game_logic(pointer.Phys_Obj player) {
+        |    player->pos.x = 15
+        |
+        |    //comment out this function call and the player
+        |    //pointer should still point to the correct location
+        |    check_player_collis_and_update_player_loc(player)
+        |    //after the function call, player points to garbage
+        |
+        |    //expected val: 15
+        |    //if player no longer points to player1: garbage
+        |    output = player->pos.x
+        |}
+        |
+        |void main() {
+        |    pointer.Phys_Obj player
+        |    player = pointer.Phys_Obj(player1.addr)
+        |    game_logic(player)
+        |}
+        |""".stripMargin
+
+    EmuCrossPlatformBenchmarkRun(Cpu.Mos)(src) { m =>
+      m.readByte(0xc000) should equal(15)
+    }
+  }
+}