Add spectre mitigation (#15)

Author: adityapatwardhan

build.psm1

@@ -222,13 +222,7 @@ function Start-BuildNativeWindowsBinaries {
 
     $atlBaseFound = $false
 
-    if ($vcPath) {
-        $atlMfcIncludePath = Join-Path -Path $vcPath -ChildPath 'atlmfc/include'
-        if(Test-Path -Path "$atlMfcIncludePath\atlbase.h") {
-            Write-Verbose -Verbose "ATLF MFC found under $atlMfcIncludePath\atlbase.h"
-            $atlBaseFound = $true
-        }
-    } elseif ($alternateVCPath) {
+    if ($alternateVCPath) {
         foreach($candidatePath in $alternateVCPath) {
             Write-Verbose -Verbose "Looking under $candidatePath"
             $atlMfcIncludePath = @(Get-ChildItem -Path $candidatePath -Recurse -Filter 'atlbase.h' -File)
@@ -241,6 +235,12 @@ function Start-BuildNativeWindowsBinaries {
                 }
             }
         }
+    } elseif ($vcPath) {
+        $atlMfcIncludePath = Join-Path -Path $vcPath -ChildPath 'atlmfc/include'
+        if(Test-Path -Path "$atlMfcIncludePath\atlbase.h") {
+            Write-Verbose -Verbose "ATLF MFC found under $atlMfcIncludePath\atlbase.h"
+            $atlBaseFound = $true
+        }
     } else {
         Write-Verbose -Verbose "PATH: $env:PATH"
         throw "Visual Studio tools not found in PATH."

src/powershell-native/coreclr_defs.cmake

@@ -47,11 +47,11 @@ set(CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_SHARED_LINKER_FLAGS_RELWIT
 set(CMAKE_STATIC_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_STATIC_LINKER_FLAGS_RELWITHDEBINFO} /LTCG")
 set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO} /LTCG /OPT:REF /OPT:ICF ${NO_INCREMENTAL_LINKER_FLAGS}")
 
-# Force uCRT to be dynamically linked for Release build  
-set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} /NODEFAULTLIB:libucrt.lib /DEFAULTLIB:ucrt.lib")  
-set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} /NODEFAULTLIB:libucrt.lib /DEFAULTLIB:ucrt.lib")  
-set(CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO} /NODEFAULTLIB:libucrt.lib /DEFAULTLIB:ucrt.lib")  
-set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO} /NODEFAULTLIB:libucrt.lib /DEFAULTLIB:ucrt.lib") 
+# Force uCRT to be dynamically linked for Release build
+set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "${CMAKE_SHARED_LINKER_FLAGS_RELEASE} /NODEFAULTLIB:libucrt.lib /DEFAULTLIB:ucrt.lib")
+set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} /NODEFAULTLIB:libucrt.lib /DEFAULTLIB:ucrt.lib")
+set(CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_SHARED_LINKER_FLAGS_RELWITHDEBINFO} /NODEFAULTLIB:libucrt.lib /DEFAULTLIB:ucrt.lib")
+set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO} /NODEFAULTLIB:libucrt.lib /DEFAULTLIB:ucrt.lib")
 
 #------------------------------------
 # Definitions (for platform)
@@ -133,16 +133,18 @@ if (BUILD_ARCH_AMD64)
 endif (BUILD_ARCH_AMD64)
 
 # enable control-flow-guard support for native components for non-Arm64 builds
-add_compile_options(/guard:cf) 
-
-# Statically linked CRT (libcmt[d].lib, libvcruntime[d].lib and libucrt[d].lib) by default. This is done to avoid  
-# linking in VCRUNTIME140.DLL for a simplified xcopy experience by reducing the dependency on VC REDIST.  
-#  
-# For Release builds, we shall dynamically link into uCRT [ucrtbase.dll] (which is pushed down as a Windows Update on downlevel OS) but  
-# wont do the same for debug/checked builds since ucrtbased.dll is not redistributable and Debug/Checked builds are not  
-# production-time scenarios.  
-add_compile_options($<$<OR:$<CONFIG:Release>,$<CONFIG:Relwithdebinfo>>:/MT>)  
-add_compile_options($<$<OR:$<CONFIG:Debug>,$<CONFIG:Checked>>:/MTd>)  
+add_compile_options(/guard:cf)
+
+# Statically linked CRT (libcmt[d].lib, libvcruntime[d].lib and libucrt[d].lib) by default. This is done to avoid
+# linking in VCRUNTIME140.DLL for a simplified xcopy experience by reducing the dependency on VC REDIST.
+#
+# For Release builds, we shall dynamically link into uCRT [ucrtbase.dll] (which is pushed down as a Windows Update on downlevel OS) but
+# wont do the same for debug/checked builds since ucrtbased.dll is not redistributable and Debug/Checked builds are not
+# production-time scenarios.
+add_compile_options($<$<OR:$<CONFIG:Release>,$<CONFIG:Relwithdebinfo>>:/MT>)
+add_compile_options($<$<OR:$<CONFIG:Debug>,$<CONFIG:Checked>>:/MTd>)
+
+add_compile_options(/Qspectre) # add Spectre mitigation compiler option. (https://docs.microsoft.com/en-us/cpp/build/reference/qspectre?view=vs-2017)
 
 #set(CMAKE_ASM_MASM_FLAGS "${CMAKE_ASM_MASM_FLAGS} /ZH:SHA_256")