From 8006635636f29cdf65e5c1ea6a092c44c9b05f36 Mon Sep 17 00:00:00 2001
From: Akos Kiss <akiss@inf.u-szeged.hu>
Date: Thu, 12 Nov 2015 12:24:02 +0100
Subject: [PATCH] Pass -Wno-error to linker in case of LTO builds

When linking a release-built command line shell on Linux against
default glibc with LTO enabled, a long-open gcc bug causes spurious
warning to be emitted around a call to fread. The `-Werror` flag
turns this into an error and the build process fails.
Unfortunately, there is no way to selectively disable the warning
with pragmas or `-Wno-error=xxx` flags.

Thus, this patch introduces some helper macros and lists all
warnings explicitly with `-Werror=xxx` instead of covering all
warnings with the `-Werror` flag. This way, warnings enabled by
command line flags do cause errors, but those raised by warning
attributes (which cannot be suppressed by any `-Wno-error=xxx`
flags) don't.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu
---
 CMakeLists.txt | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 39203a85b6..f5ad2cbfb7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -240,15 +240,31 @@ project (Jerry CXX C ASM)
   set(COMPILE_FLAGS_JERRY "${COMPILE_FLAGS_JERRY} -g -gdwarf-4")
 
  # Warnings
-  set(COMPILE_FLAGS_JERRY "${COMPILE_FLAGS_JERRY} -Wall -Wextra -pedantic")
-  set(COMPILE_FLAGS_JERRY "${COMPILE_FLAGS_JERRY} -Wformat-nonliteral -Winit-self -Wno-stack-protector")
-  set(COMPILE_FLAGS_JERRY "${COMPILE_FLAGS_JERRY} -Wconversion -Wsign-conversion -Wformat-security")
-  set(COMPILE_FLAGS_JERRY "${COMPILE_FLAGS_JERRY} -Wmissing-declarations -Wno-attributes")
-  set(COMPILE_FLAGS_JERRY "${COMPILE_FLAGS_JERRY} -Wfatal-errors")
+  macro(append variable value)
+    set(${variable} "${${variable}} ${value}")
+  endmacro()
+
+  macro(add_jerry_compile_flags)
+    foreach(_flag ${ARGV})
+      append(COMPILE_FLAGS_JERRY ${_flag})
+    endforeach()
+  endmacro()
+
+  macro(add_jerry_compile_warnings)
+    foreach(_warning ${ARGV})
+      add_jerry_compile_flags(-W${_warning})
+      if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX)
+        add_jerry_compile_flags(-Werror=${_warning})
+      endif()
+    endforeach()
+  endmacro()
+
+  add_jerry_compile_warnings(all extra format-nonliteral init-self conversion sign-conversion format-security missing-declarations)
+  add_jerry_compile_flags(-pedantic -Wno-stack-protector -Wno-attributes -Wfatal-errors)
   if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX)
-    set(COMPILE_FLAGS_JERRY "${COMPILE_FLAGS_JERRY} -Werror -Wlogical-op")
+    add_jerry_compile_warnings(logical-op)
   else()
-    set(COMPILE_FLAGS_JERRY "${COMPILE_FLAGS_JERRY} -Wno-nested-anon-types")
+    add_jerry_compile_flags(-Wno-nested-anon-types)
   endif()
 
  # Static build