CI, make: enable ASAN for tests

and document it

.github/workflows/test.yaml

@@ -90,6 +90,6 @@ jobs:
       with:
         submodules: recursive
     - name: Build DEBUG
-      run: make native CONF=DEBUG ${{ matrix.extra_make_args }} -j4
+      run: make native CONF=DEBUG WITH_ASAN=true ${{ matrix.extra_make_args }} -j4
     - name: Run tests
-      run: make test CONF=DEBUG ${{ matrix.extra_make_args }}
+      run: make test CONF=DEBUG WITH_ASAN=true ${{ matrix.extra_make_args }} -j4

CONTRIBUTING.md

@@ -69,7 +69,7 @@ See [scan-build.yaml](../.github/workflows/scan-build.yaml).
 
 ### Address Sanitizer
 
-Consider testing with ASAN.
+Consider testing with ASAN by passing WITH_ASAN=true to make.
 
 ### Spell Checker
 

Makefile

@@ -168,8 +168,6 @@ ifeq ($(CONF), DEBUG) # DEBUG
     CPP_FLAGS = -Wall -Wnon-virtual-dtor -Wno-unused-function -Wno-deprecated-declarations -fstack-protector-all -g -Og -ffunction-sections -fdata-sections -pthread -fno-omit-frame-pointer
     LD_FLAGS = -Wl,--gc-sections -fstack-protector-all -pthread -fno-omit-frame-pointer
   endif
-  #CPP_FLAGS += -fsanitize=address
-  #LD_FLAGS += -fsanitize=address
 else # RELEASE or DIST
   C_FLAGS += -O2 -fno-stack-protector -fno-common
   LUA_CFALGS += -O2 -fno-stack-protector -fno-common
@@ -185,6 +183,11 @@ else # RELEASE or DIST
   endif
 endif
 
+ifdef WITH_ASAN
+CPP_FLAGS += -fsanitize=address
+LD_FLAGS += -fsanitize=address
+endif
+
 CPP_FLAGS += -DLUA_CPP
 
 # os-specific tool config