DO NOT MERGE: Tmp commit to build with more compilers in CI to detect issues.

Author: microbit-carlos

.github/workflows/build.yml

@@ -11,8 +11,8 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-20.04, macos-11, windows-2019]
-        gcc: ['7-2017-q4', 'latest']
-        cmake: ['3.6.0', '']  # Empty string installs the latest CMake release
+        gcc: ['7-2017-q4', '7-2018-q2', '8-2018-q4', '8-2019-q3', '9-2019-q4', '9-2020-q2', '10-2020-q4', 'latest']
+        cmake: ['3.6.0']  #, '']  # Empty string installs the latest CMake release
       fail-fast: false
     runs-on: ${{ matrix.os }}
     name: ${{ matrix.os }}, gcc ${{ matrix.gcc }}, cmake ${{ matrix.cmake || 'latest'}}

utils/cmake/toolchains/ARM_GCC/compiler-flags.cmake

@@ -6,6 +6,18 @@ if((CMAKE_VERSION VERSION_GREATER "3.4.0") OR (CMAKE_VERSION VERSION_EQUAL "3.4.
     set(EXPLICIT_INCLUDES "<INCLUDES> ")
 endif()
 
+
+#if(CMAKE_C_COMPILER_VERSION VERSION_GREATER "9.0.0" OR CMAKE_C_COMPILER_VERSION VERSION_EQUAL "9.0.0")
+    # Some tools are not compatible with DWARF v5 yet
+    set(DWARF_VERSION_FLAG "-gdwarf-4")
+    message("USING DWARF v4 (${CMAKE_C_COMPILER_VERSION})")
+#else()
+    # Older gcc versions need to be configured with DWARF v3
+#    set(DWARF_VERSION_FLAG "-gdwarf-3")
+#    message("USING DWARF v3 (${CMAKE_C_COMPILER_VERSION})")
+#endif()
+
+
 # Override the link rules:
 set(CMAKE_C_CREATE_SHARED_LIBRARY "echo 'shared libraries not supported' && 1")
 set(CMAKE_C_CREATE_SHARED_MODULE  "echo 'shared modules not supported' && 1")
@@ -19,29 +31,29 @@ set(CMAKE_DEPFILE_FLAGS_CXX "-MMD -MT <OBJECT> -MF <DEPFILE>")
 set(CMAKE_C_OUTPUT_EXTENSION ".o")
 set(CMAKE_DEPFILE_FLAGS_C "-MMD -MT <OBJECT> -MF <DEPFILE>")
 
-set(CMAKE_C_FLAGS_RELWITHDEBINFO      "-g -gdwarf-4")
-set(CMAKE_C_FLAGS_DEBUG_INIT          "-g -gdwarf-4")
+set(CMAKE_C_FLAGS_RELWITHDEBINFO      "-g ${DWARF_VERSION_FLAG}")
+set(CMAKE_C_FLAGS_DEBUG_INIT          "-g ${DWARF_VERSION_FLAG}")
 set(CMAKE_C_FLAGS_MINSIZEREL_INIT     "-Os -DNDEBUG")
 set(CMAKE_C_FLAGS_RELEASE_INIT        "-Os -DNDEBUG")
-set(CMAKE_C_FLAGS_RELWITHDEBINFO_INIT "-Os -g -gdwarf-4 -DNDEBUG")
+set(CMAKE_C_FLAGS_RELWITHDEBINFO_INIT "-Os -g ${DWARF_VERSION_FLAG} -DNDEBUG")
 set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-isystem ")
 
-set(CMAKE_ASM_FLAGS_RELWITHDEBINFO      "-g -gdwarf-4")
-set(CMAKE_ASM_FLAGS_DEBUG_INIT          "-g -gdwarf-4")
+set(CMAKE_ASM_FLAGS_RELWITHDEBINFO      "-g ${DWARF_VERSION_FLAG}")
+set(CMAKE_ASM_FLAGS_DEBUG_INIT          "-g ${DWARF_VERSION_FLAG}")
 set(CMAKE_ASM_FLAGS_MINSIZEREL_INIT     "-Os -DNDEBUG")
 set(CMAKE_ASM_FLAGS_RELEASE_INIT        "-Os -DNDEBUG")
-set(CMAKE_ASM_FLAGS_RELWITHDEBINFO_INIT "-Os -g -gdwarf-4 -DNDEBUG")
+set(CMAKE_ASM_FLAGS_RELWITHDEBINFO_INIT "-Os -g ${DWARF_VERSION_FLAG} -DNDEBUG")
 set(CMAKE_INCLUDE_SYSTEM_FLAG_ASM  "-isystem ")
 
 set(CMAKE_CXX_CREATE_STATIC_LIBRARY "<CMAKE_AR> -cr <LINK_FLAGS> <TARGET> <OBJECTS>")
 
 set(CMAKE_CXX_LINK_EXECUTABLE       "<CMAKE_CXX_COMPILER> <CMAKE_CXX_LINK_FLAGS> <LINK_FLAGS> -Wl,-Map,<TARGET>.map -Wl,--start-group <OBJECTS> <LINK_LIBRARIES> -lnosys -lstdc++ -lsupc++ -lm -lc -lgcc -lstdc++ -lsupc++ -lm -lc -lgcc -Wl,--end-group  --specs=nano.specs -o <TARGET>")
 
-set(CMAKE_CXX_FLAGS_RELWITHDEBINFO      "-g -gdwarf-4")
-set(CMAKE_CXX_FLAGS_DEBUG_INIT          "-g -gdwarf-4")
+set(CMAKE_CXX_FLAGS_RELWITHDEBINFO      "-g ${DWARF_VERSION_FLAG}")
+set(CMAKE_CXX_FLAGS_DEBUG_INIT          "-g ${DWARF_VERSION_FLAG}")
 set(CMAKE_CXX_FLAGS_MINSIZEREL_INIT     "-Os -DNDEBUG")
 set(CMAKE_CXX_FLAGS_RELEASE_INIT        "-Os -DNDEBUG")
-set(CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT "-Os -g -gdwarf-4 -DNDEBUG")
+set(CMAKE_CXX_FLAGS_RELWITHDEBINFO_INIT "-Os -g ${DWARF_VERSION_FLAG} -DNDEBUG")
 set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "-isystem ")
 
 if (CMAKE_C_COMPILER_VERSION VERSION_GREATER "7.1.0" OR CMAKE_C_COMPILER_VERSION VERSION_EQUAL "7.1.0")