From 27ec25fee753da60d36ce560ce34b9cef7dc8df7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Tue, 24 May 2016 12:36:17 +0200
Subject: beam_expect: Correctly handle blocks with multiple allocs

A negative allocation could be calculated if a block had multiple
allocations. Make sure to process the block in the right order
so that the correct allocation is processed. Also add an assertion.

This bug was often not noticed because beam_type usually silently
recalculates the allocation amount in test_heap/2 instructions.
---
 lib/compiler/src/beam_except.erl        |  8 +++++---
 lib/compiler/test/beam_except_SUITE.erl | 26 +++++++++++++++++++++++---
 2 files changed, 28 insertions(+), 6 deletions(-)

(limited to 'lib/compiler')

diff --git a/lib/compiler/src/beam_except.erl b/lib/compiler/src/beam_except.erl
index cb3a6b79de..4a181c1923 100644
--- a/lib/compiler/src/beam_except.erl
+++ b/lib/compiler/src/beam_except.erl
@@ -133,10 +133,12 @@ translate_exception(_, _, _, _) -> no.
 fix_block(Is, 0) ->
     reverse(Is);
 fix_block(Is, Words) ->
-    fix_block_1(reverse(Is), Words).
+    reverse(fix_block_1(Is, Words)).
 
-fix_block_1([{set,[],[],{alloc,Live,{F1,F2,Needed,F3}}}|Is], Words) ->
-    [{set,[],[],{alloc,Live,{F1,F2,Needed-Words,F3}}}|Is];
+fix_block_1([{set,[],[],{alloc,Live,{F1,F2,Needed0,F3}}}|Is], Words) ->
+    Needed = Needed0 - Words,
+    true = Needed >= 0,				%Assertion.
+    [{set,[],[],{alloc,Live,{F1,F2,Needed,F3}}}|Is];
 fix_block_1([I|Is], Words) ->
     [I|fix_block_1(Is, Words)].
 
diff --git a/lib/compiler/test/beam_except_SUITE.erl b/lib/compiler/test/beam_except_SUITE.erl
index 8746e62fb9..47367d6eab 100644
--- a/lib/compiler/test/beam_except_SUITE.erl
+++ b/lib/compiler/test/beam_except_SUITE.erl
@@ -21,15 +21,18 @@
 
 -export([all/0, suite/0,groups/0,init_per_suite/1, end_per_suite/1,
 	 init_per_group/2,end_per_group/2,
-	 coverage/1]).
+	 multiple_allocs/1,coverage/1]).
 
 suite() -> [{ct_hooks,[ts_install_cth]}].
 
 all() ->
-    [coverage].
+    test_lib:recompile(?MODULE),
+    [{group,p}].
 
 groups() ->
-    [].
+    [{p,[parallel],
+      [multiple_allocs,
+       coverage]}].
 
 init_per_suite(Config) ->
     Config.
@@ -43,6 +46,23 @@ init_per_group(_GroupName, Config) ->
 end_per_group(_GroupName, Config) ->
     Config.
 
+multiple_allocs(_Config) ->
+    {'EXIT',{{badmatch,#{true:=[p]}},_}} =
+	 (catch could(pda, 0.0, {false,true}, {p})),
+    {'EXIT',{function_clause,_}} = (catch place(lee)),
+    {'EXIT',{{badmatch,wanted},_}} = (catch conditions()),
+
+    ok.
+
+could(Coupons = pda, Favorite = _pleasure = 0.0, {_, true}, {Presents}) ->
+  (0 = true) = #{true => [Presents]}.
+
+place(lee) ->
+    (pregnancy = presentations) = [hours | [purchase || _ <- 0]] + wine.
+
+conditions() ->
+    (talking = going) = storage + [large = wanted].
+
 coverage(_) ->
     File = {file,"fake.erl"},
     ok = fc(a),
-- 
cgit v1.2.3