CMake: support RelWithDebInfo builds

Adapt open-simh PR 475 by B. Scott Michel by allowing RelWithDebInfo in
the CMake helper scripts and documenting it as an optimized build with
debugger information.

Apply the existing optimized GNU/Clang flag handling to RelWithDebInfo,
but do not import unrelated warning suppressions or change MSVC LTO
behavior.

Author: pmetzger

BUILDING.md

@@ -287,6 +287,9 @@ cmake --build build/release --target integration-tests
 
 Some useful CMake options:
 
+- `-DCMAKE_BUILD_TYPE=RelWithDebInfo`
+  Build optimized binaries while retaining debugger information. This is
+  useful for profiling, debugger sessions, and tools such as Valgrind.
 - `-DWITH_VIDEO=Off`
   Disable SDL-based graphics support. Default: `On`.
 - `-DWITH_NETWORK=Off`

README-CMake.md

@@ -99,7 +99,9 @@ The most commonly used options are:
 
 - `CMAKE_BUILD_TYPE`
   Default: generator-dependent.
-  Use `Release` or `Debug` for single-config generators such as Ninja.
+  Use `Release`, `Debug`, or `RelWithDebInfo` for single-config
+  generators such as Ninja. `RelWithDebInfo` is optimized like a release
+  build while retaining debugger information.
 - `WITH_VIDEO`
   Default: `On`.
   Enable SDL-based graphics and display support.

cmake/cmake-builder.ps1

@@ -14,7 +14,8 @@ simulators using the CMake meta-build tool. The phases are:
 2. Build missing runtime dependencies and the simulator suite with the compiler
    configuration selected by the '-config' option. The "Release" configuration
    generates optimized executables; the "Debug" configuration generates
-   development executables with debugger information.
+   development executables with debugger information; and "RelWithDebInfo"
+   generates optimized executables with debugger information.
 3. Test the simulators
 
 There is an install phase that can be invoked separately as part of the SIMH
@@ -86,7 +87,8 @@ param (
     [Parameter(Mandatory=$false)]
     [string] $flavor         = "vs2022",
 
-    ## The target build configuration. Valid values: "Release" and "Debug"
+    ## The target build configuration. Valid values are "Release", "Debug",
+    ## and "RelWithDebInfo"
     [Parameter(Mandatory=$false)]
     [string] $config         = "Release",
 
@@ -294,7 +296,7 @@ if (!$testonly)
 }
 
 ## Validate the requested configuration.
-if (!@("Release", "Debug").Contains($config))
+if (!@("Release", "Debug", "RelWithDebInfo").Contains($config))
 {
     @"
 ${scriptName}: Invalid configuration: "${config}".

cmake/cmake-builder.sh

@@ -12,7 +12,7 @@ Configure and build simh simulators on Linux and *nix-like platforms.
 --clean (-x)      Remove the build subdirectory
 --generate (-g)   Generate the build environment, don't compile/build
 --cache           '--generate' and show CMake's variable cache
---parallel (-p)   Enable build parallelism (parallel builds)
+--parallel (-p)   Enable parallel builds
 --notest          Do not execute 'ctest' test cases
 --noinstall       Do not install SIMH simulators.
 --testonly        Do not build, execute the 'ctest' test cases
@@ -27,7 +27,8 @@ Configure and build simh simulators on Linux and *nix-like platforms.
                     msys2
                     mingw
                     ucrt
---config (-c)     Specifies the build configuration: 'Release' or 'Debug'
+--config (-c)     Specifies the build configuration: 'Release', 'Debug', or
+                  'RelWithDebInfo'
 
 --target          Build a specific simulator or simulators. Separate multiple
                   targets with a comma, e.g. "--target pdp8,pdp11,vax750,altairz80,3b2-400"
@@ -211,7 +212,7 @@ while true; do
             ;;
         -c | --config)
             case "$2" in
-                Release|Debug)
+                Release|Debug|RelWithDebInfo)
                     buildConfig=$2
                     shift 2
                     ;;

cmake/platform-quirks.cmake

@@ -136,7 +136,7 @@ if (CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID MATCHES ".*Clang")
     ## LIST(APPEND EXTRA_TARGET_CFLAGS "-Wall" "-fno-inline" "-fstrict-overflow" "-Wstrict-overflow=3")
     LIST(APPEND EXTRA_TARGET_CFLAGS
         "$<$<CONFIG:Debug>:$<$<OR:$<BOOL:${DEBUG_WALL}>,$<BOOL:${DEBUG_WARNINGS}>>:-Wall>>"
-        "$<$<CONFIG:Release>:-Wall>"
+        "$<$<CONFIG:Release,RelWithDebInfo>:-Wall>"
         "$<$<CONFIG:Debug>:$<$<BOOL:${DEBUG_WARNINGS}>:-Wextra>>"
         # Keep this warning disabled for now; legacy aggregate
         # initializers produce too much noise during warning sweeps.
@@ -198,22 +198,26 @@ if (CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID MATCHES ".*Clang")
             endif ()
         endif ()
 
-        message(STATUS "Adding GNU-specific optimizations to CMAKE_C_FLAGS_RELEASE")
+        message(STATUS "Adding GNU-specific optimizations to optimized build flags")
         list(APPEND opt_flags "-finline-functions" "-fgcse-after-reload" "-fpredictive-commoning"
                             "-fipa-cp-clone" "-fno-unsafe-loop-optimizations")
     elseif (CMAKE_C_COMPILER_ID MATCHES ".*Clang")
-        message(STATUS "Adding Clang-specific optimizations to CMAKE_C_FLAGS_RELEASE")
+        message(STATUS "Adding Clang-specific optimizations to optimized build flags")
     endif()
 
     foreach (opt_flag ${opt_flags})
         message(STATUS "    ${opt_flag}")
-        string(REGEX REPLACE "${opt_flag}[ \t\r\n]*" "" CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE}")
-        string(APPEND CMAKE_C_FLAGS_RELEASE " ${opt_flag}")
-        string(REGEX REPLACE "${opt_flag}[ \t\r\n]*" "" CMAKE_C_FLAGS_MINSIZEREL "${CMAKE_C_FLAGS_MINSIZEREL}")
-        string(APPEND CMAKE_C_FLAGS_MINSIZEREL " ${opt_flag}")
+        foreach (optimized_c_flags_var
+                 CMAKE_C_FLAGS_RELEASE
+                 CMAKE_C_FLAGS_RELWITHDEBINFO
+                 CMAKE_C_FLAGS_MINSIZEREL)
+            string(REGEX REPLACE "${opt_flag}[ \t\r\n]*" ""
+                   ${optimized_c_flags_var} "${${optimized_c_flags_var}}")
+            string(APPEND ${optimized_c_flags_var} " ${opt_flag}")
+        endforeach ()
     endforeach ()
 else ()
-    message(STATUS "Not changing CMAKE_C_FLAGS_RELEASE on ${CMAKE_C_COMPILER_ID}")
+    message(STATUS "Not changing optimized build flags on ${CMAKE_C_COMPILER_ID}")
 endif ()