capstone: Convert Makefile bits to meson bits

There are better ways to do this, e.g. meson cmake subproject,
but that requires cmake 3.7 and some of our CI environments
only provide cmake 3.5.

Nor can we add a meson.build file to capstone/, because the git
submodule would then always report "untracked files".  Fixing that
would require creating our own branch on the qemu git mirror, at
which point we could just as easily create a native meson subproject.

Instead, build the library via the main meson.build.

This improves the current state of affairs in that we will re-link
the qemu executables against a changed libcapstone.a, which we wouldn't
do before-hand.  In addition, the use of the configuration header file
instead of command-line -DEFINES means that we will rebuild the
capstone objects with changes to meson.build.

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

4 files changed, 120 insertions, 80 deletions

diff --git a/Makefile b/Makefile
index 54fc1a9d10..f27bd4b2eb 100644
--- a/Makefile
+++ b/Makefile
@@ -156,21 +156,11 @@ dtc/all: .git-submodule-status dtc/libfdt
 dtc/%: .git-submodule-status
 	@mkdir -p $@
 
-# Overriding CFLAGS causes us to lose defines added in the sub-makefile.
-# Not overriding CFLAGS leads to mis-matches between compilation modes.
-# Therefore we replicate some of the logic in the sub-makefile.
-# Remove all the extra -Warning flags that QEMU uses that Capstone doesn't;
-# no need to annoy QEMU developers with such things.
-CAP_CFLAGS = $(patsubst -W%,,$(CFLAGS) $(QEMU_CFLAGS)) $(CAPSTONE_CFLAGS)
-CAP_CFLAGS += -DCAPSTONE_USE_SYS_DYN_MEM
-CAP_CFLAGS += -DCAPSTONE_HAS_ARM
-CAP_CFLAGS += -DCAPSTONE_HAS_ARM64
-CAP_CFLAGS += -DCAPSTONE_HAS_POWERPC
-CAP_CFLAGS += -DCAPSTONE_HAS_X86
-
+# Retain for a while so that incremental build across this patch
+# does not raise an error for missing target "capstone/all", which
+# comes from the saved SUBDIRS value.
 .PHONY: capstone/all
-capstone/all: .git-submodule-status
-	$(call quiet-command,$(MAKE) -C $(SRC_PATH)/capstone CAPSTONE_SHARED=no BUILDDIR="$(BUILD_DIR)/capstone" CC="$(CC)" AR="$(AR)" LD="$(LD)" RANLIB="$(RANLIB)" CFLAGS="$(CAP_CFLAGS)" $(SUBDIR_MAKEFLAGS) $(BUILD_DIR)/capstone/$(LIBCAPSTONE))
+capstone/all:
 
 .PHONY: slirp/all
 slirp/all: .git-submodule-status
diff --git a/configure b/configure
index a5841241be..f46f433649 100755
--- a/configure
+++ b/configure
@@ -478,7 +478,7 @@ opengl=""
 opengl_dmabuf="no"
 cpuid_h="no"
 avx2_opt=""
-capstone=""
+capstone="auto"
 lzo=""
 snappy=""
 bzip2=""
@@ -1575,11 +1575,11 @@ for opt do
   ;;
   --enable-vhost-kernel) vhost_kernel="yes"
   ;;
-  --disable-capstone) capstone="no"
+  --disable-capstone) capstone="disabled"
   ;;
-  --enable-capstone) capstone="yes"
+  --enable-capstone) capstone="enabled"
   ;;
-  --enable-capstone=git) capstone="git"
+  --enable-capstone=git) capstone="internal"
   ;;
   --enable-capstone=system) capstone="system"
   ;;
@@ -5017,51 +5017,11 @@ fi
 # capstone
 
 case "$capstone" in
-  "" | yes)
-    if $pkg_config capstone; then
-      capstone=system
-    elif test -e "${source_path}/.git" && test $git_update = 'yes' ; then
-      capstone=git
-    elif test -e "${source_path}/capstone/Makefile" ; then
-      capstone=internal
-    elif test -z "$capstone" ; then
-      capstone=no
-    else
-      feature_not_found "capstone" "Install capstone devel or git submodule"
-    fi
-    ;;
-
-  system)
-    if ! $pkg_config capstone; then
-      feature_not_found "capstone" "Install capstone devel"
-    fi
-    ;;
-esac
-
-case "$capstone" in
-  git | internal)
-    if test "$capstone" = git; then
+  auto | enabled | internal)
+    # Simpler to always update submodule, even if not needed.
+    if test -e "${source_path}/.git" && test $git_update = 'yes' ; then
       git_submodules="${git_submodules} capstone"
     fi
-    mkdir -p capstone
-    if test "$mingw32" = "yes"; then
-      LIBCAPSTONE=capstone.lib
-    else
-      LIBCAPSTONE=libcapstone.a
-    fi
-    capstone_libs="-Lcapstone -lcapstone"
-    capstone_cflags="-I${source_path}/capstone/include"
-    ;;
-
-  system)
-    capstone_libs="$($pkg_config --libs capstone)"
-    capstone_cflags="$($pkg_config --cflags capstone)"
-    ;;
-
-  no)
-    ;;
-  *)
-    error_exit "Unknown state for capstone: $capstone"
     ;;
 esac
 
@@ -7142,11 +7102,6 @@ fi
 if test "$ivshmem" = "yes" ; then
   echo "CONFIG_IVSHMEM=y" >> $config_host_mak
 fi
-if test "$capstone" != "no" ; then
-  echo "CONFIG_CAPSTONE=y" >> $config_host_mak
-  echo "CAPSTONE_CFLAGS=$capstone_cflags" >> $config_host_mak
-  echo "CAPSTONE_LIBS=$capstone_libs" >> $config_host_mak
-fi
 if test "$debug_mutex" = "yes" ; then
   echo "CONFIG_DEBUG_MUTEX=y" >> $config_host_mak
 fi
@@ -7664,13 +7619,7 @@ done # for target in $targets
 if [ "$fdt" = "git" ]; then
   subdirs="$subdirs dtc"
 fi
-if [ "$capstone" = "git" -o "$capstone" = "internal" ]; then
-  subdirs="$subdirs capstone"
-fi
 echo "SUBDIRS=$subdirs" >> $config_host_mak
-if test -n "$LIBCAPSTONE"; then
-  echo "LIBCAPSTONE=$LIBCAPSTONE" >> $config_host_mak
-fi
 
 if test "$numa" = "yes"; then
   echo "CONFIG_NUMA=y" >> $config_host_mak
@@ -7846,7 +7795,8 @@ NINJA=${ninja:-$PWD/ninjatool} $meson setup \
 	-Dmalloc=$malloc -Dmalloc_trim=$malloc_trim \
 	-Dcocoa=$cocoa -Dmpath=$mpath -Dsdl=$sdl -Dsdl_image=$sdl_image \
 	-Dvnc=$vnc -Dvnc_sasl=$vnc_sasl -Dvnc_jpeg=$vnc_jpeg -Dvnc_png=$vnc_png \
-	-Dgettext=$gettext -Dxkbcommon=$xkbcommon -Du2f=$u2f\
+	-Dgettext=$gettext -Dxkbcommon=$xkbcommon -Du2f=$u2f \
+	-Dcapstone=$capstone \
         $cross_arg \
         "$PWD" "$source_path"
 
diff --git a/meson.build b/meson.build
index 3161c1f037..b9f6e84c2b 100644
--- a/meson.build
+++ b/meson.build
@@ -10,6 +10,7 @@ else
   keyval = import('unstable-keyval')
 endif
 ss = import('sourceset')
+fs = import('fs')
 
 sh = find_program('sh')
 cc = meson.get_compiler('c')
@@ -495,11 +496,6 @@ if 'CONFIG_USB_LIBUSB' in config_host
   libusb = declare_dependency(compile_args: config_host['LIBUSB_CFLAGS'].split(),
                               link_args: config_host['LIBUSB_LIBS'].split())
 endif
-capstone = not_found
-if 'CONFIG_CAPSTONE' in config_host
-  capstone = declare_dependency(compile_args: config_host['CAPSTONE_CFLAGS'].split(),
-                                link_args: config_host['CAPSTONE_LIBS'].split())
-endif
 libpmem = not_found
 if 'CONFIG_LIBPMEM' in config_host
   libpmem = declare_dependency(compile_args: config_host['LIBPMEM_CFLAGS'].split(),
@@ -581,7 +577,6 @@ foreach k, v: config_host
     config_host_data.set(k, v == 'y' ? 1 : v)
   endif
 endforeach
-genh += configure_file(output: 'config-host.h', configuration: config_host_data)
 
 minikconf = find_program('scripts/minikconf.py')
 config_all = {}
@@ -736,6 +731,107 @@ config_all += {
   'CONFIG_ALL': true,
 }
 
+# Submodules
+
+capstone = not_found
+capstone_opt = get_option('capstone')
+if capstone_opt in ['enabled', 'auto', 'system']
+  have_internal = fs.exists(meson.current_source_dir() / 'capstone/Makefile')
+  capstone = dependency('capstone', static: enable_static,
+                        method: 'pkg-config',
+                        required: capstone_opt == 'system' or
+                                  capstone_opt == 'enabled' and not have_internal)
+  if capstone.found()
+    capstone_opt = 'system'
+  elif have_internal
+    capstone_opt = 'internal'
+  else
+    capstone_opt = 'disabled'
+  endif
+endif
+if capstone_opt == 'internal'
+  capstone_data = configuration_data()
+  capstone_data.set('CAPSTONE_USE_SYS_DYN_MEM', '1')
+
+  capstone_files = files(
+    'capstone/cs.c',
+    'capstone/MCInst.c',
+    'capstone/MCInstrDesc.c',
+    'capstone/MCRegisterInfo.c',
+    'capstone/SStream.c',
+    'capstone/utils.c'
+  )
+
+  if 'CONFIG_ARM_DIS' in config_all_disas
+    capstone_data.set('CAPSTONE_HAS_ARM', '1')
+    capstone_files += files(
+      'capstone/arch/ARM/ARMDisassembler.c',
+      'capstone/arch/ARM/ARMInstPrinter.c',
+      'capstone/arch/ARM/ARMMapping.c',
+      'capstone/arch/ARM/ARMModule.c'
+    )
+  endif
+
+  # FIXME: This config entry currently depends on a c++ compiler.
+  # Which is needed for building libvixl, but not for capstone.
+  if 'CONFIG_ARM_A64_DIS' in config_all_disas
+    capstone_data.set('CAPSTONE_HAS_ARM64', '1')
+    capstone_files += files(
+      'capstone/arch/AArch64/AArch64BaseInfo.c',
+      'capstone/arch/AArch64/AArch64Disassembler.c',
+      'capstone/arch/AArch64/AArch64InstPrinter.c',
+      'capstone/arch/AArch64/AArch64Mapping.c',
+      'capstone/arch/AArch64/AArch64Module.c'
+    )
+  endif
+
+  if 'CONFIG_PPC_DIS' in config_all_disas
+    capstone_data.set('CAPSTONE_HAS_POWERPC', '1')
+    capstone_files += files(
+      'capstone/arch/PowerPC/PPCDisassembler.c',
+      'capstone/arch/PowerPC/PPCInstPrinter.c',
+      'capstone/arch/PowerPC/PPCMapping.c',
+      'capstone/arch/PowerPC/PPCModule.c'
+    )
+  endif
+
+  if 'CONFIG_I386_DIS' in config_all_disas
+    capstone_data.set('CAPSTONE_HAS_X86', 1)
+    capstone_files += files(
+      'capstone/arch/X86/X86Disassembler.c',
+      'capstone/arch/X86/X86DisassemblerDecoder.c',
+      'capstone/arch/X86/X86ATTInstPrinter.c',
+      'capstone/arch/X86/X86IntelInstPrinter.c',
+      'capstone/arch/X86/X86Mapping.c',
+      'capstone/arch/X86/X86Module.c'
+    )
+  endif
+
+  configure_file(output: 'capstone-defs.h', configuration: capstone_data)
+
+  capstone_cargs = [
+    # FIXME: There does not seem to be a way to completely replace the c_args
+    # that come from add_project_arguments() -- we can only add to them.
+    # So: disable all warnings with a big hammer.
+    '-Wno-error', '-w',
+
+    # Include all configuration defines via a header file, which will wind up
+    # as a dependency on the object file, and thus changes here will result
+    # in a rebuild.
+    '-include', 'capstone-defs.h'
+  ]
+
+  libcapstone = static_library('capstone',
+                               sources: capstone_files,
+                               c_args: capstone_cargs,
+                               include_directories: 'capstone/include')
+  capstone = declare_dependency(link_with: libcapstone,
+                                include_directories: 'capstone/include')
+endif
+config_host_data.set('CONFIG_CAPSTONE', capstone.found())
+
+genh += configure_file(output: 'config-host.h', configuration: config_host_data)
+
 # Generators
 
 hxtool = find_program('scripts/hxtool')
@@ -1566,7 +1662,7 @@ summary_info += {'vvfat support':     config_host.has_key('CONFIG_VVFAT')}
 summary_info += {'qed support':       config_host.has_key('CONFIG_QED')}
 summary_info += {'parallels support': config_host.has_key('CONFIG_PARALLELS')}
 summary_info += {'sheepdog support':  config_host.has_key('CONFIG_SHEEPDOG')}
-summary_info += {'capstone':          config_host.has_key('CONFIG_CAPSTONE')}
+summary_info += {'capstone':          capstone_opt == 'disabled' ? false : capstone_opt}
 summary_info += {'libpmem support':   config_host.has_key('CONFIG_LIBPMEM')}
 summary_info += {'libdaxctl support': config_host.has_key('CONFIG_LIBDAXCTL')}
 summary_info += {'libudev':           libudev.found()}
diff --git a/meson_options.txt b/meson_options.txt
index 46ea1d889a..a1228d29a9 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -31,3 +31,7 @@ option('vnc_sasl', type : 'feature', value : 'auto',
        description: 'SASL authentication for VNC server')
 option('xkbcommon', type : 'feature', value : 'auto',
        description: 'xkbcommon support')
+
+option('capstone', type: 'combo', value: 'auto',
+       choices: ['disabled', 'enabled', 'auto', 'system', 'internal'],
+       description: 'Whether and how to find the capstone library')