From 4b05be4265c0ffacfce26d7db7644ffbf9037696 Mon Sep 17 00:00:00 2001
From: Jose Dapena Paz <jose.dapena@lge.com>
Date: Tue, 26 Jun 2018 11:47:15 +0200
Subject: [PATCH] linux: fix ARM snapshot context traits build.
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On GCC with libstdc++, ContextTraits fail to build because of the missing
declaration of offsetof (should include cstddef) and for aliasing a type
with the same name overriding previous declaration.

Change-Id: Ic497238122bcb430f14f9234644c483a8e27e3b6
Reviewed-on: https://chromium-review.googlesource.com/1114606
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: José Dapena Paz <jose.dapena@lge.com>
---
 snapshot/linux/exception_snapshot_linux.cc | 4 ++--
 snapshot/linux/signal_context.h            | 9 +++++----
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/snapshot/linux/exception_snapshot_linux.cc b/snapshot/linux/exception_snapshot_linux.cc
index 6e2a9275..c57e072e 100644
--- a/snapshot/linux/exception_snapshot_linux.cc
+++ b/snapshot/linux/exception_snapshot_linux.cc
@@ -130,7 +130,7 @@ bool ExceptionSnapshotLinux::ReadContext<ContextTraits32>(
 
   LinuxVMAddress gprs_address =
       context_address + offsetof(UContext<ContextTraits32>, mcontext32) +
-      offsetof(MContext32, gprs);
+      offsetof(ContextTraits32::MContext32, gprs);
 
   SignalThreadContext32 thread_context;
   if (!memory->Read(gprs_address, sizeof(thread_context), &thread_context)) {
@@ -207,7 +207,7 @@ bool ExceptionSnapshotLinux::ReadContext<ContextTraits64>(
 
   LinuxVMAddress gprs_address =
       context_address + offsetof(UContext<ContextTraits64>, mcontext64) +
-      offsetof(MContext64, gprs);
+      offsetof(ContextTraits64::MContext64, gprs);
 
   ThreadContext::t64_t thread_context;
   if (!memory->Read(gprs_address, sizeof(thread_context), &thread_context)) {
diff --git a/snapshot/linux/signal_context.h b/snapshot/linux/signal_context.h
index f9d2cb9d..98844151 100644
--- a/snapshot/linux/signal_context.h
+++ b/snapshot/linux/signal_context.h
@@ -19,6 +19,7 @@
 #include <stdint.h>
 #include <sys/types.h>
 
+#include <cstddef>
 #include <type_traits>
 
 #include "build/build_config.h"
@@ -244,7 +245,7 @@ struct SignalThreadContext32 {
 
 using SignalThreadContext64 = ThreadContext::t64_t;
 
-struct MContext32 {
+struct MContext32Data {
   uint32_t trap_no;
   uint32_t error_code;
   uint32_t oldmask;
@@ -252,19 +253,19 @@ struct MContext32 {
   uint32_t fault_address;
 };
 
-struct MContext64 {
+struct MContext64Data {
   uint64_t fault_address;
   SignalThreadContext64 gprs;
 };
 
 struct ContextTraits32 : public Traits32 {
-  using MContext32 = MContext32;
+  using MContext32 = MContext32Data;
   using MContext64 = Nothing;
 };
 
 struct ContextTraits64 : public Traits64 {
   using MContext32 = Nothing;
-  using MContext64 = MContext64;
+  using MContext64 = MContext64Data;
 };
 
 template <typename Traits>