Clarify and slightly modify the use of C compiler related make variab…

…les.

Before this commit, there was no distinction between the options
used to compile C source files coming with the OCaml distribution
and third-party C source files compiled by calling ocamlc or ocamlopt.

This commit makes it possible to use options when compiling C source
files that come with OCaml without imposing these options to the compilation
of third-party code.

More specifically, the options in the BYTECCCOMPOPTS and NATIVECCCOMPOPTS
variables are not passed to the C compiler when called by ocamlc and
ocamlopt any longer.

This commit also documents the role of each concerned variable.

In addition:

- On Unix:
  * The -Wall and -Werror options are no longer passed to the C
    compiler by ocamlc and ocamlopt for third-party C source files

- For the MinGW port:
  * The -O option has been removed from the SHAREDCCCOMPOPTS variable
  * The -Wall and -Wno-unused options are no longer passed to the C
    compiler by ocamlc and ocamlopt for third-party C source files

- For the msvc port: the
  * The -Ox option has been removed from the SHAREDCCCOMPOPTS variable.
  * The -Wall and -Wno-unused options are no longer passed to the C
    compiler by ocamlc and ocamlopt for third-party C source files

Changes

@@ -31,6 +31,10 @@ Next version (4.05.0):
 - GPR#829: better error when opening a module aliased to a functor
   (Alain Frisch)
 
+- GPR#911: ocamlc/ocamlopt do not pass warnings-related options to C
+  compiler when called to compile third-party C source files
+  (Sébastien Hinderer)
+
 ### Standard library:
 
 - GPR#760: Add a functions List.compare_lengths and

Makefile

@@ -407,8 +407,8 @@ utils/config.ml: utils/config.mlp config/Makefile
 	sed -e 's|%%LIBDIR%%|$(LIBDIR)|' \
 	    -e 's|%%BYTERUN%%|$(BINDIR)/ocamlrun|' \
 	    -e 's|%%CCOMPTYPE%%|cc|' \
-	    -e 's|%%BYTECC%%|$(BYTECC) $(BYTECCCOMPOPTS) $(SHAREDCCCOMPOPTS)|' \
-	    -e 's|%%NATIVECC%%|$(NATIVECC) $(NATIVECCCOMPOPTS)|' \
+	    -e 's|%%BYTECC%%|$(BYTECC) $(SHAREDCCCOMPOPTS)|' \
+	    -e 's|%%NATIVECC%%|$(NATIVECC)|' \
 	    -e '/c_compiler =/s| -Werror||' \
 	    -e 's|%%PACKLD%%|$(PACKLD)|' \
 	    -e 's|%%BYTECCLIBS%%|$(BYTECCLIBS)|' \

Makefile.nt

@@ -374,8 +374,8 @@ utils/config.ml: utils/config.mlp config/Makefile
 	sed -e "s|%%LIBDIR%%|$(LIBDIR)|" \
 	    -e "s|%%BYTERUN%%|ocamlrun|" \
 	    -e 's|%%CCOMPTYPE%%|$(CCOMPTYPE)|' \
-	    -e "s|%%BYTECC%%|$(BYTECC) $(BYTECCCOMPOPTS)|" \
-	    -e "s|%%NATIVECC%%|$(NATIVECC) $(NATIVECCCOMPOPTS)|" \
+	    -e "s|%%BYTECC%%|$(BYTECC)|" \
+	    -e "s|%%NATIVECC%%|$(NATIVECC)|" \
 	    -e "s|%%PARTIALLD%%|$(PARTIALLD)|" \
 	    -e "s|%%PACKLD%%|$(PACKLD)|" \
 	    -e "s|%%BYTECCLIBS%%|$(BYTECCLIBS)|" \

config/Makefile.mingw

@@ -68,7 +68,7 @@ X11_INCLUDES=
 X11_LINK=
 BYTECCRPATH=
 SUPPORTS_SHARED_LIBRARIES=true
-SHAREDCCCOMPOPTS=-O
+SHAREDCCCOMPOPTS=
 MKSHAREDLIBRPATH=
 NATIVECCPROFOPTS=
 NATIVECCRPATH=
@@ -98,10 +98,10 @@ SAFE_STRING=false
 ########## Configuration for the bytecode compiler
 
 ### Which C compiler to use for the bytecode interpreter.
-BYTECC=$(TOOLPREF)gcc
+BYTECC=$(TOOLPREF)gcc -O -mms-bitfields
 
 ### Additional compile-time options for $(BYTECC).  (For static linking.)
-BYTECCCOMPOPTS=-O -mms-bitfields -Wall -Wno-unused
+BYTECCCOMPOPTS=-Wall -Wno-unused
 
 ### Additional link-time options for $(BYTECC).  (For static linking.)
 BYTECCLINKOPTS=
@@ -168,7 +168,7 @@ SYSTEM=mingw
 NATIVECC=$(BYTECC)
 
 ### Additional compile-time options for $(NATIVECC).
-NATIVECCCOMPOPTS=-O -mms-bitfields -Wall -Wno-unused
+NATIVECCCOMPOPTS=-Wall -Wno-unused
 
 ### Additional link-time options for $(NATIVECC)
 NATIVECCLINKOPTS=

config/Makefile.mingw64

@@ -68,7 +68,7 @@ X11_INCLUDES=
 X11_LINK=
 BYTECCRPATH=
 SUPPORTS_SHARED_LIBRARIES=true
-SHAREDCCCOMPOPTS=-O
+SHAREDCCCOMPOPTS=
 MKSHAREDLIBRPATH=
 NATIVECCPROFOPTS=
 NATIVECCRPATH=
@@ -98,10 +98,10 @@ SAFE_STRING=false
 ########## Configuration for the bytecode compiler
 
 ### Which C compiler to use for the bytecode interpreter.
-BYTECC=$(TOOLPREF)gcc
+BYTECC=$(TOOLPREF)gcc -O -mms-bitfields
 
 ### Additional compile-time options for $(BYTECC).  (For static linking.)
-BYTECCCOMPOPTS=-O -mms-bitfields -Wall -Wno-unused
+BYTECCCOMPOPTS=-Wall -Wno-unused
 
 ### Additional link-time options for $(BYTECC).  (For static linking.)
 BYTECCLINKOPTS=
@@ -168,7 +168,7 @@ SYSTEM=mingw64
 NATIVECC=$(BYTECC)
 
 ### Additional compile-time options for $(NATIVECC).
-NATIVECCCOMPOPTS=-O -mms-bitfields -Wall -Wno-unused
+NATIVECCCOMPOPTS=-Wall -Wno-unused
 
 ### Additional link-time options for $(NATIVECC)
 NATIVECCLINKOPTS=

config/Makefile.msvc

@@ -63,7 +63,7 @@ X11_INCLUDES=
 X11_LINK=
 BYTECCRPATH=
 SUPPORTS_SHARED_LIBRARIES=true
-SHAREDCCCOMPOPTS=-Ox
+SHAREDCCCOMPOPTS=
 NATIVECCPROFOPTS=
 NATIVECCRPATH=
 ASM=ml -nologo -coff -Cp -c -Fo
@@ -92,10 +92,10 @@ SAFE_STRING=false
 ########## Configuration for the bytecode compiler
 
 ### Which C compiler to use for the bytecode interpreter.
-BYTECC=cl -nologo -D_CRT_SECURE_NO_DEPRECATE
+BYTECC=cl -nologo -D_CRT_SECURE_NO_DEPRECATE -O2 -Gy- -MD
 
 ### Additional compile-time options for $(BYTECC).  (For static linking.)
-BYTECCCOMPOPTS=-O2 -Gy- -MD
+BYTECCCOMPOPTS=
 
 ### Additional link-time options for $(BYTECC).  (For static linking.)
 BYTECCLINKOPTS=
@@ -163,10 +163,10 @@ MODEL=default
 SYSTEM=win32
 
 ### Which C compiler to use for the native-code compiler.
-NATIVECC=cl -nologo -D_CRT_SECURE_NO_DEPRECATE
+NATIVECC=cl -nologo -D_CRT_SECURE_NO_DEPRECATE -O2 -Gy- -MD
 
 ### Additional compile-time options for $(NATIVECC).
-NATIVECCCOMPOPTS=-O2 -Gy- -MD
+NATIVECCCOMPOPTS=
 
 ### Additional link-time options for $(NATIVECC)
 NATIVECCLINKOPTS=

config/Makefile.msvc64

@@ -63,7 +63,7 @@ X11_INCLUDES=
 X11_LINK=
 BYTECCRPATH=
 SUPPORTS_SHARED_LIBRARIES=true
-SHAREDCCCOMPOPTS=-Ox
+SHAREDCCCOMPOPTS=
 NATIVECCPROFOPTS=
 NATIVECCRPATH=
 ASM=ml64 -nologo -Cp -c -Fo
@@ -91,10 +91,10 @@ SAFE_STRING=false
 ########## Configuration for the bytecode compiler
 
 ### Which C compiler to use for the bytecode interpreter.
-BYTECC=cl -nologo -D_CRT_SECURE_NO_DEPRECATE
+BYTECC=cl -nologo -D_CRT_SECURE_NO_DEPRECATE -O2 -Gy- -MD
 
 ### Additional compile-time options for $(BYTECC).  (For static linking.)
-BYTECCCOMPOPTS=-O2 -Gy- -MD
+BYTECCCOMPOPTS=
 
 ### Additional compile-time options for $(BYTECC).  (For debug version.)
 BYTECCDBGCOMPOPTS=-DDEBUG -Zi -W3 -Wp64
@@ -168,10 +168,10 @@ MODEL=default
 SYSTEM=win64
 
 ### Which C compiler to use for the native-code compiler.
-NATIVECC=cl -nologo
+NATIVECC=cl -nologo -O2 -Gy- -MD
 
 ### Additional compile-time options for $(NATIVECC).
-NATIVECCCOMPOPTS=-O2 -Gy- -MD
+NATIVECCCOMPOPTS=
 
 ### Additional link-time options for $(NATIVECC)
 NATIVECCLINKOPTS=

configure

@@ -328,10 +328,29 @@ esac
 
 # Configure the bytecode compiler
 
+# The BYTECC make variable defines which compiler and options to use
+# to compile C code intended to be used by OCaml bytecode programs.
+# It is used inside OCaml's build system, and also when ocamlc is
+# called on a third-party C source file and no -cc command-line option
+# has been specified.
+
+# The BYTECCCOMPOPTS make variable contains options to pass to the C
+# compiler but only when compiling C files that belong to the OCaml
+# distribution.
+# In other words, when ocamlc is called to compile a third-party C
+# source file, it will _not_ pass these options to the C compiler.
+
+# The SHAREDCCCOMPOPTS make variable contains options to use to compile C
+# source files so that the resulting object files can then be integrated
+# into shared libraries. It is passed to BYTECC for both C source files
+# in the OCaml distribution and third-party C source files compiled
+# with ocamlc.
+
 bytecc="$cc"
 mkexe="\$(BYTECC)"
 mkexedebugflag="-g"
 bytecccompopts=""
+byteccprivatecompopts=""
 bytecclinkopts=""
 ostype="Unix"
 exe=""
@@ -357,7 +376,8 @@ esac
 
 case "$ccfamily" in
   clang-*)
-    bytecccompopts="-O2 -fno-strict-aliasing -fwrapv $gcc_warnings";;
+    bytecccompopts="-O2 -fno-strict-aliasing -fwrapv";
+    byteccprivatecompopts="$gcc_warnings";;
   gcc-[012]-*)
     # Some versions known to miscompile OCaml, e,g, 2.7.2.1, some 2.96.
     # Plus: C99 support unknown.
@@ -367,11 +387,14 @@ case "$ccfamily" in
     # Known problems with -fwrapv fixed in 4.2 only.
     wrn "This version of GCC is rather old.  Reducing optimization level."
     wrn "Consider using GCC version 4.2 or above."
-    bytecccompopts="-std=gnu99 -O $gcc_warnings";;
+    bytecccompopts="-std=gnu99 -O";
+    byteccprivatecompopts="$gcc_warnings";;
   gcc-4-*)
-    bytecccompopts="-std=gnu99 -O2 -fno-strict-aliasing -fwrapv $gcc_warnings";;
+    bytecccompopts="-std=gnu99 -O2 -fno-strict-aliasing -fwrapv";
+    byteccprivatecompopts="$gcc_warnings";;
   gcc-*)
-    bytecccompopts="-O2 -fno-strict-aliasing -fwrapv $gcc_warnings";;
+    bytecccompopts="-O2 -fno-strict-aliasing -fwrapv";
+    byteccprivatecompopts="$gcc_warnings";;
   *)
     bytecccompopts="-O";;
 esac
@@ -487,7 +510,7 @@ export cc cclibs verbose
 
 # Check C compiler.
 
-cc="$bytecc $bytecccompopts $bytecclinkopts" sh ./runtest ansi.c
+cc="$bytecc $bytecccompopts $byteccprivatecompopts $bytecclinkopts" sh ./runtest ansi.c
 case $? in
   0) inf "The C compiler is ISO C99 compliant." ;;
   1) wrn "The C compiler is ANSI / ISO C90 compliant, but not ISO C99" \
@@ -843,6 +866,18 @@ fi
 
 # Configure the native-code compiler
 
+# The NATIVECC make variable defines which compiler and options to use
+# to compile C code intended to be used by OCaml native programs.
+# It is used inside OCaml's build system, and also when ocamlopt is
+# called on a third-party C source file and no -cc command-line
+# option has been specified.
+
+# The NATIVECCCOMPOPTS make variable contains options to pass to the C
+# compiler, but only when compiling C files that belong to the OCaml
+# distribution.
+# In other words, when ocamlopt is called to compile a third-party C
+# source file, it will _not_ pass these options to the C compiler.
+
 arch=none
 model=default
 system=unknown
@@ -925,6 +960,7 @@ else
 fi
 
 nativecccompopts="$bytecccompopts"
+nativeccprivatecompopts=byteccprivatecompopts
 nativeccprofopts=''
 nativecclinkopts=''
 # FIXME the naming of nativecclinkopts is broken: these are options for
@@ -1920,8 +1956,8 @@ fi
 
 cclibs="$cclibs $mathlib"
 
-echo "BYTECC=$bytecc" >> Makefile
-echo "BYTECCCOMPOPTS=$bytecccompopts" >> Makefile
+echo "BYTECC=$bytecc $bytecccompopts" >> Makefile
+echo "BYTECCCOMPOPTS=$byteccprivatecompopts" >> Makefile
 echo "BYTECCLINKOPTS=$bytecclinkopts" >> Makefile
 echo "BYTECCLIBS=$cclibs $dllib $curseslibs $pthread_link \
                  $instrumented_runtime_libs" >> Makefile
@@ -1944,8 +1980,8 @@ EOF
 echo "ARCH=$arch" >> Makefile
 echo "MODEL=$model" >> Makefile
 echo "SYSTEM=$system" >> Makefile
-echo "NATIVECC=$nativecc" >> Makefile
-echo "NATIVECCCOMPOPTS=$nativecccompopts" >> Makefile
+echo "NATIVECC=$nativecc $nativecccompopts" >> Makefile
+echo "NATIVECCCOMPOPTS=$nativeprivatecccompopts" >> Makefile
 echo "NATIVECCPROFOPTS=$nativeccprofopts" >> Makefile
 echo "NATIVECCLINKOPTS=$nativecclinkopts" >> Makefile
 echo "NATIVECCRPATH=$nativeccrpath" >> Makefile