From 03afaae12811632cf975586728826af14a634ad1 Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Fri, 22 Jan 2016 20:12:40 +0100
Subject: erts: Beautify some code with container_of macro

---
 erts/emulator/beam/erl_bif_trace.c | 11 ++++-------
 erts/emulator/beam/sys.h           |  3 +++
 2 files changed, 7 insertions(+), 7 deletions(-)

(limited to 'erts')

diff --git a/erts/emulator/beam/erl_bif_trace.c b/erts/emulator/beam/erl_bif_trace.c
index ff2018aa27..09c82ad206 100644
--- a/erts/emulator/beam/erl_bif_trace.c
+++ b/erts/emulator/beam/erl_bif_trace.c
@@ -1307,7 +1307,7 @@ erts_set_trace_pattern(Process*p, Eterm* mfa, int specified,
 
     for (i = 0; i < n; i++) {
 	BeamInstr* pc = fp[i].pc;
-	Export* ep = (Export *)(((char *)(pc-3)) - offsetof(Export, code));
+	Export* ep = ErtsContainerStruct(pc, Export, code[3]);
 
 	if (on && !flags.breakpoint) {
 	    /* Turn on global call tracing */
@@ -1556,11 +1556,10 @@ install_exp_breakpoints(BpFunctions* f)
     BpFunction* fp = f->matching;
     Uint ne = f->matched;
     Uint i;
-    Uint offset = offsetof(Export, code) + 3*sizeof(BeamInstr);
 
     for (i = 0; i < ne; i++) {
 	BeamInstr* pc = fp[i].pc;
-	Export* ep = (Export *) (((char *)pc)-offset);
+	Export* ep = ErtsContainerStruct(pc, Export, code[3]);
 
 	ep->addressv[code_ix] = pc;
     }
@@ -1573,11 +1572,10 @@ uninstall_exp_breakpoints(BpFunctions* f)
     BpFunction* fp = f->matching;
     Uint ne = f->matched;
     Uint i;
-    Uint offset = offsetof(Export, code) + 3*sizeof(BeamInstr);
 
     for (i = 0; i < ne; i++) {
 	BeamInstr* pc = fp[i].pc;
-	Export* ep = (Export *) (((char *)pc)-offset);
+	Export* ep = ErtsContainerStruct(pc, Export, code[3]);
 
 	if (ep->addressv[code_ix] != pc) {
 	    continue;
@@ -1594,11 +1592,10 @@ clean_export_entries(BpFunctions* f)
     BpFunction* fp = f->matching;
     Uint ne = f->matched;
     Uint i;
-    Uint offset = offsetof(Export, code) + 3*sizeof(BeamInstr);
 
     for (i = 0; i < ne; i++) {
 	BeamInstr* pc = fp[i].pc;
-	Export* ep = (Export *) (((char *)pc)-offset);
+	Export* ep = ErtsContainerStruct(pc, Export, code[3]);
 
 	if (ep->addressv[code_ix] == pc) {
 	    continue;
diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
index 748fba15c7..dda3ba565c 100644
--- a/erts/emulator/beam/sys.h
+++ b/erts/emulator/beam/sys.h
@@ -92,6 +92,9 @@
 #define ErtsInArea(ptr,start,nbytes) \
     ((UWord)((char*)(ptr) - (char*)(start)) < (nbytes))
 
+#define ErtsContainerStruct(ptr, type, member) \
+  (type *)((char *)(1 ? (ptr) : &((type *)0)->member) - offsetof(type, member))
+
 #if defined (__WIN32__)
 #  include "erl_win_sys.h"
 #else
-- 
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