File 0190-beam_ssa_opt-Don-t-optimize-constants-larg... of Package erlang

Overview Repositories Revisions Requests Users Attributes Meta

File 0190-beam_ssa_opt-Don-t-optimize-constants-larger-than-1-.patch of Package erlang (Revision b1ddc78860c1f178c6361caad002e77d)

Currently displaying revision b1ddc78860c1f178c6361caad002e77d , Show latest

From d8a23287b45b74e7c01dd9bd358d0a2fec3ef2ce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20H=C3=B6gberg?= <john@erlang.org>
Date: Mon, 9 Jan 2023 10:31:35 +0100
Subject: [PATCH] beam_ssa_opt: Don't optimize constants larger than 1<<24 bits

---
 lib/compiler/src/beam_ssa_opt.erl        | 16 +++++++++-------
 lib/compiler/test/bs_construct_SUITE.erl |  5 +++++
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/lib/compiler/src/beam_ssa_opt.erl b/lib/compiler/src/beam_ssa_opt.erl
index fecb5bebd5..435c6773f3 100644
--- a/lib/compiler/src/beam_ssa_opt.erl
+++ b/lib/compiler/src/beam_ssa_opt.erl
@@ -2100,18 +2100,20 @@ opt_create_bin_arg(Type, Unit, Flags, #b_literal{val=Val}, #b_literal{val=Size})
   when is_integer(Size), is_integer(Unit) ->
     EffectiveSize = Size * Unit,
     if
-        EffectiveSize > 0 ->
+        EffectiveSize > (1 bsl 24) ->
+            %% Don't bother converting really huge segments as they might fail
+            %% with a `system_limit` exception in runtime. Keeping them as-is
+            %% ensures that the extended error information will be accurate.
+            %%
+            %% We'll also reduce the risk of crashing with an unhelpful "out of
+            %% memory" error message during compilation.
+            not_possible;
+        EffectiveSize > 0, EffectiveSize =< (1 bsl 24) ->
             case {Type,opt_create_bin_endian(Flags)} of
                 {integer,big} when is_integer(Val) ->
                     if
                         EffectiveSize < 64 ->
                             [<<Val:EffectiveSize>>];
-                        EffectiveSize > 1 bsl 24 ->
-                            %% The binary construction could fail with a
-                            %% system_limit. Don't optimize to ensure that
-                            %% the extended error information will be
-                            %% accurate.
-                            not_possible;
                         true ->
                             opt_bs_put_split_int(Val, EffectiveSize)
                     end;
diff --git a/lib/compiler/test/bs_construct_SUITE.erl b/lib/compiler/test/bs_construct_SUITE.erl
index cecc3660d4..93cee3c189 100644
--- a/lib/compiler/test/bs_construct_SUITE.erl
+++ b/lib/compiler/test/bs_construct_SUITE.erl
@@ -522,6 +522,11 @@ nasty_literals(Config) when is_list(Config) ->
     I = 16#7777FFFF7777FFFF7777FFFF7777FFFF7777FFFF7777FFFF,
     id(<<I:260>>),
 
+    %% GH-6643: Excessively large literals could cause the compiler to run out
+    %% of memory.
+    catch id(<<0:16777216/big-integer-unit:1>>),
+    catch id(<<0:(16777216*2)/big-integer-unit:1>>),
+
     ok.
 
 -define(COF(Int0),
-- 
2.35.3

Places

File 0190-beam_ssa_opt-Don-t-optimize-constants-larger-than-1-.patch of Package erlang (Revision b1ddc78860c1f178c6361caad002e77d)

Places