1 files changed, 32 insertions, 36 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt
index bb8a621d7..5b382264b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -45,34 +45,33 @@ function (die msg)
   message(FATAL_ERROR "${BoldRed}${msg}${ColourReset}")
 endfunction ()
 
-if ("${ARCH}" STREQUAL "" OR "${ARCH}" STREQUAL "native")
-  set(ARCH ${CMAKE_SYSTEM_PROCESSOR})
-  message(STATUS "Building natively on ${ARCH}")
+# ARCH defines the target architecture, either by an explicit identifier or
+# one of the following two keywords. By default, ARCH a value of 'native':
+# target arch = host arch, binary is not portable. When ARCH is set to the
+# string 'default', no -march arg is passed, which creates a binary that is
+# portable across processors in the same family as host processor.  In cases
+# when ARCH is not set to an explicit identifier, cmake's builtin is used
+# to identify the target architecture, to direct logic in this cmake script.
+# Since ARCH is a cached variable, it will not be set on first cmake invocation.
+if (NOT ARCH OR ARCH STREQUAL "" OR ARCH STREQUAL "native" OR ARCH STREQUAL "default")
+  set(ARCH_ID "${CMAKE_SYSTEM_PROCESSOR}")
+else()
+  set(ARCH_ID "${ARCH}")
 endif()
-
-if (NOT "${ARCH}" STREQUAL "")
-  string(SUBSTRING ${ARCH} 0 3 IS_ARM)
-  string(TOLOWER ${IS_ARM} IS_ARM)
-
-  if (${IS_ARM} STREQUAL "arm")
-    string(SUBSTRING ${ARCH} 0 5 ARM_TEST)
-    string(TOLOWER ${ARM_TEST} ARM_TEST)
-
-    if (${ARM_TEST} STREQUAL "armv6")
-      set(ARM6 1)
-    else()
-      set(ARM6 0)
-    endif()
-
-    if (${ARM_TEST} STREQUAL "armv7")
-      set(ARM7 1)
-    else()
-      set(ARM7 0)
-    endif()
+string(TOLOWER ${ARCH_ID} ARM_ID)
+string(SUBSTRING ${ARCH_ID} 0 3 ARM_TEST)
+if (ARM_TEST STREQUAL "arm")
+  set(ARM 1)
+  string(SUBSTRING ${ARCH_ID} 0 5 ARM_TEST)
+  if (ARM_TEST STREQUAL "armv6")
+    set(ARM6 1)
+  endif()
+  if (ARM_TEST STREQUAL "armv7")
+    set(ARM7 1)
   endif()
 endif()
 
-if(WIN32 OR ARM7 OR ARM6)
+if(WIN32 OR ARM)
   set(OPT_FLAGS_RELEASE "-O2")
 else()
   set(OPT_FLAGS_RELEASE "-Ofast")
@@ -247,7 +246,8 @@ add_definitions("-DBLOCKCHAIN_DB=${BLOCKCHAIN_DB}")
 
 find_package(Libunwind)
 # Can't install hook in static build on OSX, because OSX linker does not support --wrap
-if(LIBUNWIND_FOUND AND NOT (STATIC AND APPLE))
+# On ARM, having libunwind package (with .so's only) installed breaks static link.
+if(LIBUNWIND_FOUND AND NOT (STATIC AND (APPLE OR ARM)))
   set(DEFAULT_STACK_TRACE ON)
 else()
   set(DEFAULT_STACK_TRACE OFF)
@@ -308,16 +308,12 @@ if(MSVC)
   endif()
   include_directories(SYSTEM src/platform/msc)
 else()
-  set(ARCH native CACHE STRING "CPU to build for: -march value or default")
-  # -march=armv7-a conflicts with -mcpu=cortex-a7
-  if(ARCH STREQUAL "default" OR ARM7 OR ARM6)
+  set(ARCH native CACHE STRING "CPU to build for: -march value or 'default' to not pass -march at all")
+  message(STATUS "Building on ${CMAKE_SYSTEM_PROCESSOR} for ${ARCH}")
+  if(ARCH STREQUAL "default")
     set(ARCH_FLAG "")
   else()
-    if(ARCH STREQUAL "x86_64")
-      set(ARCH_FLAG "-march=x86-64")
-    else()
-       set(ARCH_FLAG "-march=${ARCH}")
-    endif()
+    set(ARCH_FLAG "-march=${ARCH}")
   endif()
   set(WARNINGS "-Wall -Wextra -Wpointer-arith -Wundef -Wvla -Wwrite-strings -Wno-error=extra -Wno-error=deprecated-declarations -Wno-unused-parameter -Wno-unused-variable -Wno-error=unused-variable -Wno-error=undef -Wno-error=uninitialized")
   if(NOT MINGW)
@@ -325,7 +321,7 @@ else()
   endif()
   if(CMAKE_C_COMPILER_ID STREQUAL "Clang")
     set(WARNINGS "${WARNINGS} -Wno-deprecated-register -Wno-error=mismatched-tags -Wno-error=null-conversion -Wno-overloaded-shift-op-parentheses -Wno-error=shift-count-overflow -Wno-error=tautological-constant-out-of-range-compare -Wno-error=unused-private-field -Wno-error=unneeded-internal-declaration")
-    if(ARM6 OR ARM7)
+    if(ARM)
       set(WARNINGS "${WARNINGS} -Wno-error=inline-asm")
     endif()
   else()
@@ -362,11 +358,11 @@ else()
 
   option(NO_AES "Explicitly disable AES support" ${NO_AES})
 
-  if(NOT NO_AES AND NOT (ARM6 OR ARM7))
+  if(NOT NO_AES AND NOT ARM)
     message(STATUS "AES support enabled")
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -maes")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -maes")
-  elseif(ARM7 OR ARM6)
+  elseif(ARM)
     message(STATUS "AES support disabled (not available on ARM)")
   else()
     message(STATUS "AES support disabled")