File 1222-jit-Cancel-out-S_RESERVED-before-calling-G... of Package erlang

Overview Repositories Revisions Requests Users Attributes Meta

File 1222-jit-Cancel-out-S_RESERVED-before-calling-GC.patch of Package erlang (Revision afcf17dce72e3ad97ec30c595b0394c3)

Currently displaying revision afcf17dce72e3ad97ec30c595b0394c3 , Show latest

From a641723a1423510accb4483620eaeaa7a0a6c3df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?John=20H=C3=B6gberg?= <john@erlang.org>
Date: Fri, 3 Dec 2021 10:32:51 +0100
Subject: [PATCH 2/4] jit: Cancel out S_RESERVED before calling GC

S_RESERVED got added twice whenever the GC was called from the
garbage collection fragment, as it was folded into "words needed"
and then added again when the GC accounted for S_RESERVED
internally.
---
 erts/emulator/beam/jit/arm/beam_asm_global.cpp | 13 ++++++++-----
 erts/emulator/beam/jit/x86/beam_asm_global.cpp | 10 +++++++---
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/erts/emulator/beam/jit/arm/beam_asm_global.cpp b/erts/emulator/beam/jit/arm/beam_asm_global.cpp
index bcecc584ff..4ecd0e9841 100644
--- a/erts/emulator/beam/jit/arm/beam_asm_global.cpp
+++ b/erts/emulator/beam/jit/arm/beam_asm_global.cpp
@@ -102,16 +102,19 @@ BeamGlobalAssembler::BeamGlobalAssembler(JitAllocator *allocator)
     }
 }
 
-/*
- * ARG3 = (HTOP + bytes needed)
- * ARG4 = Live registers
- */
+/* ARG3 = (HTOP + S_RESERVED + bytes needed) !!
+ * ARG4 = Live registers */
 void BeamGlobalAssembler::emit_garbage_collect() {
     emit_enter_runtime_frame();
 
-    /* Convert ARG3 to words needed and move it to the correct argument slot. */
+    /* Convert ARG3 to words needed and move it to the correct argument slot.
+     *
+     * Note that we cancel out the S_RESERVED that we added in the GC check, as
+     * the GC routines handle that separately and we don't want it to be added
+     * twice. */
     a.sub(ARG2, ARG3, HTOP);
     a.lsr(ARG2, ARG2, imm(3));
+    a.sub(ARG2, ARG2, imm(S_RESERVED));
 
     /* Save our return address in c_p->i so we can tell where we crashed if we
      * did so during GC. */
diff --git a/erts/emulator/beam/jit/x86/beam_asm_global.cpp b/erts/emulator/beam/jit/x86/beam_asm_global.cpp
index 00fffcc56c..6b65c9cd88 100644
--- a/erts/emulator/beam/jit/x86/beam_asm_global.cpp
+++ b/erts/emulator/beam/jit/x86/beam_asm_global.cpp
@@ -105,15 +105,19 @@ BeamGlobalAssembler::BeamGlobalAssembler(JitAllocator *allocator)
     }
 }
 
-/* ARG3 = (HTOP + bytes needed) !!
+/* ARG3 = (HTOP + S_RESERVED + bytes needed) !!
  * ARG4 = Live registers */
 void BeamGlobalAssembler::emit_garbage_collect() {
     emit_enter_frame();
 
-    /* Convert ARG3 to words needed and move it to the correct argument slot */
+    /* Convert ARG3 to words needed and move it to the correct argument slot.
+     *
+     * Note that we cancel out the S_RESERVED that we added in the GC check, as
+     * the GC routines handle that separately and we don't want it to be added
+     * twice. */
     a.sub(ARG3, HTOP);
     a.shr(ARG3, imm(3));
-    a.mov(ARG2, ARG3);
+    a.lea(ARG2, x86::qword_ptr(ARG3, -S_RESERVED));
 
     /* Save our return address in c_p->i so we can tell where we crashed if we
      * do so during GC. */
-- 
2.31.1

Places

File 1222-jit-Cancel-out-S_RESERVED-before-calling-GC.patch of Package erlang (Revision afcf17dce72e3ad97ec30c595b0394c3)

Places