Make it possible for users for select /Zi or /ZI over /Z7 when using MSVC (#18790)

Summary:
Fixes https://github.com/pytorch/pytorch/issues/18701.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18790

Differential Revision: D14748195

Pulled By: ezyang

fbshipit-source-id: e50df1b5ca199a88d7b5ea3ea45d25d23cd31a27

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0b0bafc..f6a20cd 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -57,26 +57,6 @@ if(APPLE)
   set(CMAKE_MACOSX_RPATH ON)
 endif()
 
-# For MSVC,
-# 1. Replace /Zi and /ZI with /Z7
-# 2. Switch off incremental linking in debug builds
-if (MSVC)
-  foreach(flag_var
-      CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
-      CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
-    if(${flag_var} MATCHES "/Z[iI]")
-      string(REGEX REPLACE "/Z[iI]" "/Z7" ${flag_var} "${${flag_var}}")
-    endif(${flag_var} MATCHES "/Z[iI]")
-  endforeach(flag_var)
-  foreach(flag_var
-      CMAKE_SHARED_LINKER_FLAGS_DEBUG CMAKE_STATIC_LINKER_FLAGS_DEBUG
-      CMAKE_EXE_LINKER_FLAGS_DEBUG CMAKE_MODULE_LINKER_FLAGS_DEBUG)
-    if(${flag_var} MATCHES "/INCREMENTAL" AND NOT ${flag_var} MATCHES "/INCREMENTAL:NO")
-      string(REGEX REPLACE "/INCREMENTAL" "/INCREMENTAL:NO" ${flag_var} "${${flag_var}}")
-    endif()
-  endforeach(flag_var)
-endif(MSVC)
-
 # ---[ Options.
 # Note to developers: if you add an option below, make sure you also add it to
 # cmake/Summary.cmake so that the summary prints out the option values.
@@ -155,8 +135,36 @@ cmake_dependent_option(
 # Used when building Caffe2 through setup.py
 option(BUILDING_WITH_TORCH_LIBS "Tell cmake if Caffe2 is being built alongside torch libs" OFF)
 
+# /Z7 override option
+# When generating debug symbols, CMake default to use the flag /Zi.
+# However, it is not compatible with sccache. So we rewrite it off.
+# But some users don't use sccache; this override is for them.
+option(MSVC_Z7_OVERRIDE "Work around sccache bug by replacing /Zi and /ZI with /Z7 when using MSVC (if you are not using sccache, you can turn this OFF)" ON)
+
 SET(ONNX_NAMESPACE "onnx_c2" CACHE STRING "onnx namespace")
 
+# For MSVC,
+# 1. Replace /Zi and /ZI with /Z7
+# 2. Switch off incremental linking in debug builds
+if (MSVC)
+  if(MSVC_Z7_OVERRIDE)
+    foreach(flag_var
+        CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
+        CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
+      if(${flag_var} MATCHES "/Z[iI]")
+        string(REGEX REPLACE "/Z[iI]" "/Z7" ${flag_var} "${${flag_var}}")
+      endif(${flag_var} MATCHES "/Z[iI]")
+    endforeach(flag_var)
+  endif(MSVC_Z7_OVERRIDE)
+  foreach(flag_var
+      CMAKE_SHARED_LINKER_FLAGS_DEBUG CMAKE_STATIC_LINKER_FLAGS_DEBUG
+      CMAKE_EXE_LINKER_FLAGS_DEBUG CMAKE_MODULE_LINKER_FLAGS_DEBUG)
+    if(${flag_var} MATCHES "/INCREMENTAL" AND NOT ${flag_var} MATCHES "/INCREMENTAL:NO")
+      string(REGEX REPLACE "/INCREMENTAL" "/INCREMENTAL:NO" ${flag_var} "${${flag_var}}")
+    endif()
+  endforeach(flag_var)
+endif(MSVC)
+
 if (ANDROID OR IOS)
   set(BUILD_ATEN_MOBILE ON)
 endif()

diff --git a/cmake/Dependencies.cmake b/cmake/Dependencies.cmake
index a8236bf..2f2767b 100644 (file)
--- a/cmake/Dependencies.cmake
+++ b/cmake/Dependencies.cmake
@@ -46,13 +46,15 @@ endif()
 # 1. Replace /Zi and /ZI with /Z7
 # 2. Switch off incremental linking in debug builds
 if (MSVC)
-  foreach(flag_var
-      CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
-      CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
-    if(${flag_var} MATCHES "/Z[iI]")
-      string(REGEX REPLACE "/Z[iI]" "/Z7" ${flag_var} "${${flag_var}}")
-    endif(${flag_var} MATCHES "/Z[iI]")
-  endforeach(flag_var)
+  if(MSVC_Z7_OVERRIDE)
+    foreach(flag_var
+        CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
+        CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO)
+      if(${flag_var} MATCHES "/Z[iI]")
+        string(REGEX REPLACE "/Z[iI]" "/Z7" ${flag_var} "${${flag_var}}")
+      endif(${flag_var} MATCHES "/Z[iI]")
+    endforeach(flag_var)
+  endif(MSVC_Z7_OVERRIDE)
   foreach(flag_var
       CMAKE_SHARED_LINKER_FLAGS_DEBUG CMAKE_STATIC_LINKER_FLAGS_DEBUG
       CMAKE_EXE_LINKER_FLAGS_DEBUG CMAKE_MODULE_LINKER_FLAGS_DEBUG)

diff --git a/tools/build_pytorch_libs.py b/tools/build_pytorch_libs.py
index 9bcc405..3d53aad 100644 (file)
--- a/tools/build_pytorch_libs.py
+++ b/tools/build_pytorch_libs.py
@@ -149,6 +149,7 @@ def run_cmake(version,
     cflags = os.getenv('CFLAGS', "") + " " + os.getenv('CPPFLAGS', "")
     ldflags = os.getenv('LDFLAGS', "")
     if IS_WINDOWS:
+        cmake_defines(cmake_args, MSVC_Z7_OVERRIDE=os.getenv('MSVC_Z7_OVERRIDE', "ON"))
         cflags += " /EHa"
 
     mkdir_p(install_dir)