1 #
   2 # Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
   3 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4 #
   5 # This code is free software; you can redistribute it and/or modify it
   6 # under the terms of the GNU General Public License version 2 only, as
   7 # published by the Free Software Foundation.
   8 #
   9 # This code is distributed in the hope that it will be useful, but WITHOUT
  10 # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 # version 2 for more details (a copy is included in the LICENSE file that
  13 # accompanied this code).
  14 #
  15 # You should have received a copy of the GNU General Public License version
  16 # 2 along with this work; if not, write to the Free Software Foundation,
  17 # Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18 #
  19 # Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20 # or visit www.oracle.com if you need additional information or have any
  21 # questions.
  22 #
  23 #
  24 
  25 OS_VENDOR = $(shell uname -s)
  26 
  27 #------------------------------------------------------------------------
  28 # CC, CXX & AS
  29 
  30 # If a SPEC is not set already, then use these defaults.
  31 ifeq ($(SPEC),)
  32   # When cross-compiling the ALT_COMPILER_PATH points
  33   # to the cross-compilation toolset
  34   ifdef CROSS_COMPILE_ARCH
  35     CXX = $(ALT_COMPILER_PATH)/g++
  36     CC  = $(ALT_COMPILER_PATH)/gcc
  37     HOSTCXX = g++
  38     HOSTCC  = gcc
  39   else ifneq ($(OS_VENDOR), Darwin)
  40     CXX = g++
  41     CC  = gcc
  42     HOSTCXX = $(CXX)
  43     HOSTCC  = $(CC)
  44   endif
  45 
  46   # i486 hotspot requires -mstackrealign on Darwin.
  47   # llvm-gcc supports this in Xcode 3.2.6 and 4.0.
  48   # gcc-4.0 supports this on earlier versions.
  49   # Prefer llvm-gcc where available.
  50   ifeq ($(OS_VENDOR), Darwin)
  51     ifeq ($(origin CXX), default)
  52       CXX = llvm-g++
  53     endif
  54     ifeq ($(origin CC), default)
  55       CC  = llvm-gcc
  56     endif
  57 
  58     ifeq ($(ARCH), i486)
  59       LLVM_SUPPORTS_STACKREALIGN := $(shell \
  60        [ "0"`llvm-gcc -v 2>&1 | grep LLVM | sed -E "s/.*LLVM build ([0-9]+).*/\1/"` -gt "2333" ] \
  61        && echo true || echo false)
  62 
  63       ifeq ($(LLVM_SUPPORTS_STACKREALIGN), true)
  64         CXX32 ?= llvm-g++
  65         CC32  ?= llvm-gcc
  66       else
  67         CXX32 ?= g++-4.0
  68         CC32  ?= gcc-4.0
  69       endif
  70       CXX = $(CXX32)
  71       CC  = $(CC32)
  72     endif
  73 
  74     ifeq ($(USE_CLANG), true)
  75       CXX = clang++
  76       CC  = clang
  77     endif
  78 
  79     HOSTCXX = $(CXX)
  80     HOSTCC  = $(CC)
  81   endif
  82 
  83   AS  = $(CC) -c
  84 endif
  85 
  86 ifeq ($(OS_VENDOR), Darwin)
  87   ifeq ($(DSYMUTIL),)
  88     DSYMUTIL=dsymutil
  89   endif
  90 endif
  91 
  92 ifeq ($(USE_CLANG), true)
  93   CC_VER_MAJOR := $(shell $(CC) -v 2>&1 | grep version | sed "s/.*version \([0-9]*\.[0-9]*\).*/\1/" | cut -d'.' -f1)
  94   CC_VER_MINOR := $(shell $(CC) -v 2>&1 | grep version | sed "s/.*version \([0-9]*\.[0-9]*\).*/\1/" | cut -d'.' -f2)
  95 else
  96   # -dumpversion in gcc-2.91 shows "egcs-2.91.66". In later version, it only
  97   # prints the numbers (e.g. "2.95", "3.2.1")
  98   CC_VER_MAJOR := $(shell $(CC) -dumpversion | sed 's/egcs-//' | cut -d'.' -f1)
  99   CC_VER_MINOR := $(shell $(CC) -dumpversion | sed 's/egcs-//' | cut -d'.' -f2)
 100 endif
 101 
 102 ifeq ($(USE_CLANG), true)
 103   # Clang has precompiled headers support by default, but the user can switch
 104   # it off by using 'USE_PRECOMPILED_HEADER=0'.
 105   ifdef LP64
 106     ifeq ($(USE_PRECOMPILED_HEADER),)
 107       USE_PRECOMPILED_HEADER=1
 108     endif
 109   else
 110     # We don't support precompiled headers on 32-bit builds because there some files are
 111     # compiled with -fPIC while others are compiled without (see 'NONPIC_OBJ_FILES' rules.make)
 112     # Clang produces an error if the PCH file was compiled with other options than the actual compilation unit.
 113     USE_PRECOMPILED_HEADER=0
 114   endif
 115 
 116   ifeq ($(USE_PRECOMPILED_HEADER),1)
 117 
 118     ifndef LP64
 119       $(error " Precompiled Headers only supported on 64-bit platforms!")
 120     endif
 121 
 122     PRECOMPILED_HEADER_DIR=.
 123     PRECOMPILED_HEADER_SRC=$(GAMMADIR)/src/share/vm/precompiled/precompiled.hpp
 124     PRECOMPILED_HEADER=$(PRECOMPILED_HEADER_DIR)/precompiled.hpp.pch
 125 
 126     PCH_FLAG = -include precompiled.hpp
 127     PCH_FLAG/DEFAULT = $(PCH_FLAG)
 128     PCH_FLAG/NO_PCH = -DNO_PCH
 129     PCH_FLAG/BY_FILE = $(PCH_FLAG/$@)$(PCH_FLAG/DEFAULT$(PCH_FLAG/$@))
 130 
 131     VM_PCH_FLAG/LIBJVM = $(PCH_FLAG/BY_FILE)
 132     VM_PCH_FLAG/AOUT =
 133     VM_PCH_FLAG = $(VM_PCH_FLAG/$(LINK_INTO))
 134 
 135     # We only use precompiled headers for the JVM build
 136     CFLAGS += $(VM_PCH_FLAG)
 137 
 138     # The following files are compiled at various optimization
 139     # levels due to optimization issues encountered at the
 140     # 'OPT_CFLAGS_DEFAULT' level. The Clang compiler issues a compile
 141     # time error if there is an optimization level specification
 142     # skew between the PCH file and the C++ file.  Especially if the
 143     # PCH file is compiled at a higher optimization level than
 144     # the C++ file.  One solution might be to prepare extra optimization
 145     # level specific PCH files for the opt build and use them here, but
 146     # it's probably not worth the effort as long as only a few files
 147     # need this special handling.
 148     PCH_FLAG/loopTransform.o = $(PCH_FLAG/NO_PCH)
 149     PCH_FLAG/sharedRuntimeTrig.o = $(PCH_FLAG/NO_PCH)
 150     PCH_FLAG/sharedRuntimeTrans.o = $(PCH_FLAG/NO_PCH)
 151     PCH_FLAG/unsafe.o = $(PCH_FLAG/NO_PCH)
 152 
 153   endif
 154 else # ($(USE_CLANG), true)
 155   # check for precompiled headers support
 156   ifneq "$(shell expr \( $(CC_VER_MAJOR) \> 3 \) \| \( \( $(CC_VER_MAJOR) = 3 \) \& \( $(CC_VER_MINOR) \>= 4 \) \))" "0"
 157     # Allow the user to turn off precompiled headers from the command line.
 158     ifneq ($(USE_PRECOMPILED_HEADER),0)
 159       PRECOMPILED_HEADER_DIR=.
 160       PRECOMPILED_HEADER_SRC=$(GAMMADIR)/src/share/vm/precompiled/precompiled.hpp
 161       PRECOMPILED_HEADER=$(PRECOMPILED_HEADER_DIR)/precompiled.hpp.gch
 162     endif
 163   endif
 164 endif
 165 
 166 # -DDONT_USE_PRECOMPILED_HEADER will exclude all includes in precompiled.hpp.
 167 ifeq ($(USE_PRECOMPILED_HEADER),0)
 168   CFLAGS += -DDONT_USE_PRECOMPILED_HEADER
 169 endif
 170 
 171 #------------------------------------------------------------------------
 172 # Compiler flags
 173 
 174 # position-independent code
 175 PICFLAG = -fPIC
 176 
 177 VM_PICFLAG/LIBJVM = $(PICFLAG)
 178 VM_PICFLAG/AOUT   =
 179 VM_PICFLAG        = $(VM_PICFLAG/$(LINK_INTO))
 180 
 181 ifeq ($(JVM_VARIANT_ZERO), true)
 182   CFLAGS += $(LIBFFI_CFLAGS)
 183 endif
 184 ifeq ($(JVM_VARIANT_ZEROSHARK), true)
 185   CFLAGS += $(LIBFFI_CFLAGS)
 186   CFLAGS += $(LLVM_CFLAGS)
 187 endif
 188 CFLAGS += $(VM_PICFLAG)
 189 CFLAGS += -fno-rtti
 190 CFLAGS += -fno-exceptions
 191 ifeq ($(USE_CLANG),)
 192   CFLAGS += -pthread
 193   CFLAGS += -fcheck-new
 194   # version 4 and above support fvisibility=hidden (matches jni_x86.h file)
 195   # except 4.1.2 gives pointless warnings that can't be disabled (afaik)
 196   ifneq "$(shell expr \( $(CC_VER_MAJOR) \> 4 \) \| \( \( $(CC_VER_MAJOR) = 4 \) \& \( $(CC_VER_MINOR) \>= 3 \) \))" "0"
 197     CFLAGS += -fvisibility=hidden
 198   endif
 199 else
 200   CFLAGS += -fvisibility=hidden
 201 endif
 202 
 203 ifeq ($(USE_CLANG), true)
 204   # Before Clang 3.1, we had to pass the stack alignment specification directly to llvm with the help of '-mllvm'
 205   # Starting with version 3.1, Clang understands the '-mstack-alignment' (and rejects '-mllvm -stack-alignment')
 206   ifneq "$(shell expr \( $(CC_VER_MAJOR) \> 3 \) \| \( \( $(CC_VER_MAJOR) = 3 \) \& \( $(CC_VER_MINOR) \>= 1 \) \))" "0"
 207     STACK_ALIGNMENT_OPT = -mno-omit-leaf-frame-pointer -mstack-alignment=16
 208   else
 209     STACK_ALIGNMENT_OPT = -mno-omit-leaf-frame-pointer -mllvm -stack-alignment=16
 210   endif
 211 endif
 212 
 213 ARCHFLAG = $(ARCHFLAG/$(BUILDARCH))
 214 ARCHFLAG/i486    = -m32 -march=i586
 215 ARCHFLAG/amd64   = -m64 $(STACK_ALIGNMENT_OPT)
 216 ARCHFLAG/ia64    =
 217 ARCHFLAG/sparc   = -m32 -mcpu=v9
 218 ARCHFLAG/sparcv9 = -m64 -mcpu=v9
 219 ARCHFLAG/zero    = $(ZERO_ARCHFLAG)
 220 
 221 # Darwin-specific build flags
 222 ifeq ($(OS_VENDOR), Darwin)
 223   # Ineffecient 16-byte stack re-alignment on Darwin/IA32
 224   ARCHFLAG/i486 += -mstackrealign
 225 endif
 226 
 227 CFLAGS     += $(ARCHFLAG)
 228 AOUT_FLAGS += $(ARCHFLAG)
 229 LFLAGS     += $(ARCHFLAG)
 230 ASFLAGS    += $(ARCHFLAG)
 231 
 232 ifdef E500V2
 233 CFLAGS += -DE500V2
 234 endif
 235 
 236 # Use C++ Interpreter
 237 ifdef CC_INTERP
 238   CFLAGS += -DCC_INTERP
 239 endif
 240 
 241 # Keep temporary files (.ii, .s)
 242 ifdef NEED_ASM
 243   CFLAGS += -save-temps
 244 else
 245   CFLAGS += -pipe
 246 endif
 247 
 248 # Compiler warnings are treated as errors
 249 ifneq ($(COMPILER_WARNINGS_FATAL),false)
 250   WARNINGS_ARE_ERRORS = -Werror
 251 endif
 252 
 253 ifeq ($(USE_CLANG), true)
 254   # However we need to clean the code up before we can unrestrictedly enable this option with Clang
 255   WARNINGS_ARE_ERRORS += -Wno-logical-op-parentheses -Wno-parentheses-equality -Wno-parentheses
 256   WARNINGS_ARE_ERRORS += -Wno-switch -Wno-tautological-compare
 257 # Not yet supported by clang in Xcode 4.6.2
 258 #  WARNINGS_ARE_ERRORS += -Wno-tautological-constant-out-of-range-compare
 259   WARNINGS_ARE_ERRORS += -Wno-delete-non-virtual-dtor -Wno-deprecated -Wno-format -Wno-dynamic-class-memaccess
 260   WARNINGS_ARE_ERRORS += -Wno-empty-body
 261 endif
 262 
 263 WARNING_FLAGS = -Wpointer-arith -Wsign-compare -Wundef -Wunused-function -Wformat=2
 264 
 265 ifeq ($(USE_CLANG),)
 266   # Since GCC 4.3, -Wconversion has changed its meanings to warn these implicit
 267   # conversions which might affect the values. Only enable it in earlier versions.
 268   ifeq "$(shell expr \( $(CC_VER_MAJOR) \> 4 \) \| \( \( $(CC_VER_MAJOR) = 4 \) \& \( $(CC_VER_MINOR) \>= 3 \) \))" "0"
 269     WARNINGS_FLAGS += -Wconversion
 270   endif
 271 endif
 272 
 273 CFLAGS_WARN/DEFAULT = $(WARNINGS_ARE_ERRORS) $(WARNING_FLAGS)
 274 # Special cases
 275 CFLAGS_WARN/BYFILE = $(CFLAGS_WARN/$@)$(CFLAGS_WARN/DEFAULT$(CFLAGS_WARN/$@))
 276 # XXXDARWIN: for _dyld_bind_fully_image_containing_address
 277 ifeq ($(OS_VENDOR), Darwin)
 278   CFLAGS_WARN/os_bsd.o = $(CFLAGS_WARN/DEFAULT) -Wno-deprecated-declarations
 279 endif
 280 
 281 # optimization control flags (Used by fastdebug and release variants)
 282 OPT_CFLAGS/NOOPT=-O0
 283 OPT_CFLAGS/DEBUG=-O0
 284 OPT_CFLAGS/SIZE=-Os
 285 OPT_CFLAGS/SPEED=-O3
 286 
 287 ifeq ($(OS_VENDOR), Darwin)
 288   # use -Os by default, unless -O3 can be proved to be worth the cost, as per policy
 289   # <https://wiki.openjdk.java.net/display/MacOSXPort/Compiler+Errata>
 290   OPT_CFLAGS_DEFAULT ?= SIZE
 291 else
 292   OPT_CFLAGS_DEFAULT ?= SPEED
 293 endif
 294 
 295 # Hotspot uses very unstrict aliasing turn this optimization off
 296 # This option is added to CFLAGS rather than OPT_CFLAGS
 297 # so that OPT_CFLAGS overrides get this option too.
 298 CFLAGS += -fno-strict-aliasing
 299 
 300 ifdef OPT_CFLAGS
 301   ifneq ("$(origin OPT_CFLAGS)", "command line")
 302     $(error " Use OPT_EXTRAS instead of OPT_CFLAGS to add extra flags to OPT_CFLAGS.")
 303   endif
 304 endif
 305 
 306 OPT_CFLAGS = $(OPT_CFLAGS/$(OPT_CFLAGS_DEFAULT)) $(OPT_EXTRAS)
 307 
 308 # The gcc compiler segv's on ia64 when compiling bytecodeInterpreter.cpp
 309 # if we use expensive-optimizations
 310 ifeq ($(BUILDARCH), ia64)
 311 OPT_CFLAGS += -fno-expensive-optimizations
 312 endif
 313 
 314 # Work around some compiler bugs.
 315 ifeq ($(USE_CLANG), true)
 316   # Clang <= 6.1
 317   ifeq ($(shell expr \
 318       $(CC_VER_MAJOR) \< 6 \| \
 319       \( $(CC_VER_MAJOR) = 6 \& $(CC_VER_MINOR) \<= 1 \) \
 320     ), 1)
 321     OPT_CFLAGS/loopTransform.o += $(OPT_CFLAGS/NOOPT)
 322     OPT_CFLAGS/unsafe.o += -O1
 323   else
 324     $(error "Update compiler workarounds for Clang $(CC_VER_MAJOR).$(CC_VER_MINOR)")
 325   endif
 326 else
 327   # 6835796. Problem in GCC 4.3.0 with mulnode.o optimized compilation.
 328   ifeq ($(shell expr $(CC_VER_MAJOR) = 4 \& $(CC_VER_MINOR) = 3), 1)
 329     OPT_CFLAGS/mulnode.o += $(OPT_CFLAGS/NOOPT)
 330   endif 
 331 endif
 332 
 333 # Flags for generating make dependency flags.
 334 DEPFLAGS = -MMD -MP -MF $(DEP_DIR)/$(@:%=%.d)
 335 ifeq ($(USE_CLANG),)
 336   ifneq ($(CC_VER_MAJOR), 2)
 337     DEPFLAGS += -fpch-deps
 338   endif
 339 endif
 340 
 341 # -DDONT_USE_PRECOMPILED_HEADER will exclude all includes in precompiled.hpp.
 342 ifeq ($(USE_PRECOMPILED_HEADER),0)
 343 CFLAGS += -DDONT_USE_PRECOMPILED_HEADER
 344 endif
 345 
 346 ifeq ($(OS_VENDOR), Darwin)
 347   # Setting these parameters makes it an error to link to macosx APIs that are
 348   # newer than the given OS version and makes the linked binaries compatible even
 349   # if built on a newer version of the OS.
 350   # The expected format is X.Y.Z
 351   ifeq ($(MACOSX_VERSION_MIN),)
 352     MACOSX_VERSION_MIN=10.7.0
 353   endif
 354   # The macro takes the version with no dots, ex: 1070
 355   CFLAGS += -DMAC_OS_X_VERSION_MAX_ALLOWED=$(subst .,,$(MACOSX_VERSION_MIN)) \
 356             -mmacosx-version-min=$(MACOSX_VERSION_MIN)
 357   LDFLAGS += -mmacosx-version-min=$(MACOSX_VERSION_MIN)
 358 endif
 359 
 360 
 361 #------------------------------------------------------------------------
 362 # Assembler flags
 363 
 364 # Enforce prerpocessing of .s files
 365 ASFLAGS += -x assembler-with-cpp
 366 
 367 #------------------------------------------------------------------------
 368 # Linker flags
 369 
 370 # statically link libstdc++.so, work with gcc but ignored by g++
 371 STATIC_STDCXX = -Wl,-Bstatic -lstdc++ -Wl,-Bdynamic
 372 
 373 # Ensure use libstdc++ on clang, not libc++
 374 ifeq ($(USE_CLANG), true)
 375   LFLAGS += -stdlib=libstdc++
 376 endif
 377 
 378 ifeq ($(USE_CLANG),)
 379   # statically link libgcc and/or libgcc_s, libgcc does not exist before gcc-3.x.
 380   ifneq ($(CC_VER_MAJOR), 2)
 381     STATIC_LIBGCC += -static-libgcc
 382   endif
 383 
 384   ifneq ($(OS_VENDOR), Darwin)
 385     ifneq (, findstring(debug,$(BUILD_FLAVOR)))
 386       # for relocations read-only
 387       LFLAGS += -Xlinker -z -Xlinker relro
 388 
 389       ifeq ($(BUILD_FLAVOR), debug)
 390         # disable incremental relocations linking
 391         LFLAGS += -Xlinker -z -Xlinker now
 392       endif
 393     endif
 394   endif
 395 
 396   ifeq ($(BUILDARCH), ia64)
 397     LFLAGS += -Wl,-relax
 398   endif
 399 endif
 400 
 401 # Use $(MAPFLAG:FILENAME=real_file_name) to specify a map file.
 402 MAPFLAG = -Xlinker --version-script=FILENAME
 403 
 404 #
 405 # Shared Library
 406 #
 407 ifeq ($(OS_VENDOR), Darwin)
 408   # Standard linker flags
 409   LFLAGS +=
 410 
 411   # The apple linker has its own variant of mapfiles/version-scripts
 412   MAPFLAG = -Xlinker -exported_symbols_list -Xlinker FILENAME
 413 
 414   # Use $(SONAMEFLAG:SONAME=soname) to specify the intrinsic name of a shared obj
 415   SONAMEFLAG =
 416 
 417   # Build shared library
 418   SHARED_FLAG = -Wl,-install_name,@rpath/$(@F) -dynamiclib -compatibility_version 1.0.0 -current_version 1.0.0 $(VM_PICFLAG)
 419 
 420   # Keep symbols even they are not used
 421   #AOUT_FLAGS += -Xlinker -export-dynamic
 422 else
 423   # Enable linker optimization
 424   LFLAGS += -Xlinker -O1
 425 
 426   # Use $(SONAMEFLAG:SONAME=soname) to specify the intrinsic name of a shared obj
 427   SONAMEFLAG = -Xlinker -soname=SONAME
 428 
 429   # Build shared library
 430   SHARED_FLAG = -shared $(VM_PICFLAG)
 431 
 432   # Keep symbols even they are not used
 433   AOUT_FLAGS += -Xlinker -export-dynamic
 434 endif
 435 
 436 #------------------------------------------------------------------------
 437 # Debug flags
 438 
 439 ifeq ($(USE_CLANG), true)
 440   # Restrict the debug information created by Clang to avoid
 441   # too big object files and speed the build up a little bit
 442   # (see http://llvm.org/bugs/show_bug.cgi?id=7554)
 443   CFLAGS += -flimit-debug-info
 444 endif
 445 
 446 # Allow no optimizations.
 447 DEBUG_CFLAGS=-O0
 448 
 449 # DEBUG_BINARIES uses full -g debug information for all configs
 450 ifeq ($(DEBUG_BINARIES), true)
 451   CFLAGS += -g
 452 else
 453   # Use the stabs format for debugging information (this is the default
 454   # on gcc-2.91). It's good enough, has all the information about line
 455   # numbers and local variables, and libjvm.so is only about 16M.
 456   # Change this back to "-g" if you want the most expressive format.
 457   # (warning: that could easily inflate libjvm.so to 150M!)
 458   # Note: The Itanium gcc compiler crashes when using -gstabs.
 459   DEBUG_CFLAGS/ia64  = -g
 460   DEBUG_CFLAGS/amd64 = -g
 461   DEBUG_CFLAGS/arm   = -g
 462   DEBUG_CFLAGS/ppc   = -g
 463   DEBUG_CFLAGS += $(DEBUG_CFLAGS/$(BUILDARCH))
 464   ifeq ($(DEBUG_CFLAGS/$(BUILDARCH)),)
 465       ifeq ($(USE_CLANG), true)
 466         # Clang doesn't understand -gstabs
 467         DEBUG_CFLAGS += -g
 468       else
 469         DEBUG_CFLAGS += -gstabs
 470       endif
 471   endif
 472 
 473   ifeq ($(ENABLE_FULL_DEBUG_SYMBOLS),1)
 474     FASTDEBUG_CFLAGS/ia64  = -g
 475     FASTDEBUG_CFLAGS/amd64 = -g
 476     FASTDEBUG_CFLAGS/arm   = -g
 477     FASTDEBUG_CFLAGS/ppc   = -g
 478     FASTDEBUG_CFLAGS += $(FASTDEBUG_CFLAGS/$(BUILDARCH))
 479     ifeq ($(FASTDEBUG_CFLAGS/$(BUILDARCH)),)
 480       ifeq ($(USE_CLANG), true)
 481         # Clang doesn't understand -gstabs
 482         FASTDEBUG_CFLAGS += -g
 483       else
 484         FASTDEBUG_CFLAGS += -gstabs
 485       endif
 486     endif
 487 
 488     OPT_CFLAGS/ia64  = -g
 489     OPT_CFLAGS/amd64 = -g
 490     OPT_CFLAGS/arm   = -g
 491     OPT_CFLAGS/ppc   = -g
 492     OPT_CFLAGS += $(OPT_CFLAGS/$(BUILDARCH))
 493     ifeq ($(OPT_CFLAGS/$(BUILDARCH)),)
 494       ifeq ($(USE_CLANG), true)
 495         # Clang doesn't understand -gstabs
 496         OPT_CFLAGS += -g
 497       else
 498         OPT_CFLAGS += -gstabs
 499       endif
 500     endif
 501   endif
 502 endif
 503 
 504 ifeq ($(USE_CLANG),)
 505   # Enable bounds checking.
 506   ifeq "$(shell expr \( $(CC_VER_MAJOR) \> 3 \) )" "1"
 507     # stack smashing checks.
 508     DEBUG_CFLAGS += -fstack-protector-all --param ssp-buffer-size=1
 509   endif
 510 endif
 511 
 512 # If we are building HEADLESS, pass on to VM
 513 # so it can set the java.awt.headless property
 514 ifdef HEADLESS
 515 CFLAGS += -DHEADLESS
 516 endif
 517 
 518 # We are building Embedded for a small device
 519 # favor code space over speed
 520 ifdef MINIMIZE_RAM_USAGE
 521 CFLAGS += -DMINIMIZE_RAM_USAGE
 522 endif