From f1e953d0cf7f5669a55b1337a87e646c1262d139 Mon Sep 17 00:00:00 2001
From: "Kartik K. Agaram" <vc@akkartik.com>
Date: Wed, 22 Apr 2015 22:34:34 -0700
Subject: 1146 - yet another out-of-bounds access

There's a test in this commit, but it doesn't actually fail, because by
some accident the memory at index 2 of recipe 'f' has data at the
is_label offset and breaks out of the loop. Graah. How did I ever
misplace that "Reading One Instruction" waypoint? I could swear I was
concerned about this possibility when I implemented calls.

Today has been tough on my confidence. STL helps avoid memory leaks but
doesn't help with buffer overflows nearly as much as I thought.

Oh brilliant, valgrind caught the problem! And there weren't any others.
I feel much better.
---
 cpp/035call | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

(limited to 'cpp/035call')

diff --git a/cpp/035call b/cpp/035call
index efb4a2a7..d5867f80 100644
--- a/cpp/035call
+++ b/cpp/035call
@@ -9,6 +9,24 @@ recipe f [
 ]
 +mem: storing 4 in location 3
 
+:(scenario "return_on_fallthrough")
+recipe main [
+  f
+  1:integer <- copy 34:literal
+  2:integer <- copy 34:literal
+  3:integer <- copy 34:literal
+]
+recipe f [
+  4:integer <- copy 34:literal
+  5:integer <- copy 34:literal
+]
++run: instruction main/0
++run: instruction f/0
++run: instruction f/1
++run: instruction main/1
++run: instruction main/2
++run: instruction main/3
+
 :(before "struct routine {")
 // Everytime a recipe runs another, we interrupt it and start running the new
 // recipe. When that finishes, we continue this one where we left off.
@@ -65,15 +83,18 @@ inline bool done(routine& rr) {
   return rr.calls.empty();
 }
 
-:(before "Running one instruction")
+:(before "Running One Instruction")
 // when we reach the end of one call, we may reach the end of the one below
 // it, and the one below that, and so on
+//? trace("foo") << "0: " << pc << " " << &pc; //? 1
 while (running_at(rr) >= steps(rr).size()) {
+//?   trace("foo") << "pop"; //? 1
   rr.calls.pop();
   if (rr.calls.empty()) return;
   // todo: no results returned warning
   ++running_at(rr);
 }
+//? trace("foo") << "1: " << pc << " " << &pc; //? 1
 
 :(before "End Includes")
 #include <stack>
-- 
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