build: disable debug information on release builds

Disable the default build from emitting debug information.  This will
speed up the build and reduce the output size.  This is particularly
important for the Swift side which will emit a large amount of metadata
into the final binaries which is not stripped.

This is intended to be the default build type for CI.  For local builds,
developers may use `-BuildType RelWithDebInfo` to get debug information
emitted.

Author: compnerd

build.ps1

@@ -352,8 +352,11 @@ function Build-CMakeProject {
   TryAdd-KeyValue $Defines CMAKE_BUILD_TYPE $BuildType
   TryAdd-KeyValue $Defines CMAKE_MT "mt"
 
-  $CFlags = "/GS- /Gw /Gy /Oi /Oy /Zi /Zc:inline"
-  $CXXFlags = "/GS- /Gw /Gy /Oi /Oy /Zi /Zc:inline /Zc:__cplusplus"
+  $IsRelease = $Defines["CMAKE_BUILD_TYPE"] -eq "Release"
+  $Zi = if ($IsRelease) { "" } else { "/Zi" }
+
+  $CFlags = "/GS- /Gw /Gy /Oi /Oy $Zi /Zc:inline"
+  $CXXFlags = "/GS- /Gw /Gy /Oi /Oy $Zi /Zc:inline /Zc:__cplusplus"
   if ($UseMSVCCompilers.Contains("C")) {
     TryAdd-KeyValue $Defines CMAKE_C_COMPILER cl
     Append-FlagsDefine $Defines CMAKE_C_FLAGS $CFlags
@@ -370,13 +373,17 @@ function Build-CMakeProject {
   if ($UseBuiltCompilers.Contains("C")) {
     TryAdd-KeyValue $Defines CMAKE_C_COMPILER "$BinaryCache\1\bin\clang-cl.exe"
     TryAdd-KeyValue $Defines CMAKE_C_COMPILER_TARGET $Arch.LLVMTarget
-    Append-FlagsDefine $Defines CMAKE_C_FLAGS -gdwarf
+    if (-not $IsRelease) {
+      Append-FlagsDefine $Defines CMAKE_C_FLAGS -gdwarf
+    }
     Append-FlagsDefine $Defines CMAKE_C_FLAGS $CFlags
   }
   if ($UseBuiltCompilers.Contains("CXX")) {
     TryAdd-KeyValue $Defines CMAKE_CXX_COMPILER "$BinaryCache\1\bin\clang-cl.exe"
     TryAdd-KeyValue $Defines CMAKE_CXX_COMPILER_TARGET $Arch.LLVMTarget
-    Append-FlagsDefine $Defines CMAKE_CXX_FLAGS -gdwarf
+    if (-not $IsRelease) {
+      Append-FlagsDefine $Defines CMAKE_CXX_FLAGS -gdwarf
+    }
     Append-FlagsDefine $Defines CMAKE_CXX_FLAGS $CXXFlags
   }
   if ($UseBuiltCompilers.Contains("Swift")) {
@@ -397,11 +404,18 @@ function Build-CMakeProject {
     }
 
     # Debug Information
-    # $SwiftArgs.Add("-g -debug-info-format=codeview") | Out-Null
-    $SwiftArgs.Add("-g") | Out-Null
-    $SwiftArgs.Add("-use-ld=lld-link") | Out-Null
+    if ($IsRelease) {
+      $SwiftArgs.Add("-gnone") | Out-Null
+    } else {
+      # $SwiftArgs.Add("-g -debug-info-format=codeview") | Out-Null
+      $SwiftArgs.Add("-g") | Out-Null
+      $SwiftArgs.Add("-use-ld=lld-link") | Out-Null
+    }
     $SwiftArgs.Add("-Xlinker /INCREMENTAL:NO") | Out-Null
-    $SwiftArgs.Add("-Xlinker /DEBUG:DWARF") | Out-Null
+    if (-not $IsRelease) {
+      # $SwiftArgs.Add("-Xlinker -debug") | Out-Null
+      $SwiftArgs.Add("-Xlinker /DEBUG:DWARF") | Out-Null
+    }
 
     # Swift Requries COMDAT folding and de-duplication
     $SwiftArgs.Add("-Xlinker /OPT:REF") | Out-Null
@@ -545,6 +559,11 @@ function Build-Compilers($Arch, [switch]$Test = $false) {
       }
     }
 
+    $LLVM_ENABLE_PDB = switch ($BuildType) {
+      "Release" { "NO" }
+      default { "YES" }
+    }
+
     Build-CMakeProject `
       -Src $SourceCache\llvm-project\llvm `
       -Bin $BinaryCache\1 `
@@ -555,13 +574,17 @@ function Build-Compilers($Arch, [switch]$Test = $false) {
       -Defines ($TestingDefines + @{
         CLANG_TABLEGEN = "$BinaryCache\0\bin\clang-tblgen.exe";
         CLANG_TIDY_CONFUSABLE_CHARS_GEN = "$BinaryCache\0\bin\clang-tidy-confusable-chars-gen.exe";
+        # LLVM plays tricks with flags and prefers to use `LLVM_ENABLE_PDB` for
+        # debug information on Windows rather than the CMake handling.  This
+        # give us a sligtly faster build.
+        CMAKE_BUILD_TYPE = "Release";
         CMAKE_INSTALL_PREFIX = "$($Arch.ToolchainInstallRoot)\usr";
         LLDB_PYTHON_EXE_RELATIVE_PATH = "python.exe";
         LLDB_PYTHON_EXT_SUFFIX = ".pyd";
         LLDB_PYTHON_RELATIVE_PATH = "lib/site-packages";
         LLDB_TABLEGEN = "$BinaryCache\0\bin\lldb-tblgen.exe";
         LLVM_CONFIG_PATH = "$BinaryCache\0\bin\llvm-config.exe";
-        LLVM_ENABLE_PDB = "YES";
+        LLVM_ENABLE_PDB = $LLVM_ENABLE_PDB;
         LLVM_EXTERNAL_CMARK_SOURCE_DIR = "$SourceCache\cmark";
         LLVM_EXTERNAL_SWIFT_SOURCE_DIR = "$SourceCache\swift";
         LLVM_NATIVE_TOOL_DIR = "$BinaryCache\0\bin";
@@ -725,7 +748,7 @@ function Build-Runtime($Arch) {
       SWIFT_PATH_TO_LIBDISPATCH_SOURCE = "$SourceCache\swift-corelibs-libdispatch";
       SWIFT_PATH_TO_STRING_PROCESSING_SOURCE = "$SourceCache\swift-experimental-string-processing";
       SWIFT_PATH_TO_SWIFT_SYNTAX_SOURCE = "$SourceCache\swift-syntax";
-      CMAKE_SHARED_LINKER_FLAGS = "/DEBUG /INCREMENTAL:NO /OPT:REF /OPT:ICF";
+      CMAKE_SHARED_LINKER_FLAGS = "/INCREMENTAL:NO /OPT:REF /OPT:ICF";
     }
 
   Invoke-Program $python -c "import plistlib; print(str(plistlib.dumps({ 'DefaultProperties': { 'DEFAULT_USE_RUNTIME': 'MD' } }), encoding='utf-8'))" `