[PATCH v5 36/55] plugin: add API symbols to qemu-plugins.symbols

["Alex Bennée" <alex.bennee@linaro.org>]

From: "Emilio G. Cota" <cota@braap.org>

Signed-off-by: Emilio G. Cota <cota@braap.org>
[AJB: moved into plugins]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

---
v3
  - moved to plugins/
  - include qemu_plugin_reset
v5
  - re-trigger configure if symbols are updated
  - wrap ld checks inside if static = no
---
 Makefile                     |  7 ++++
 configure                    | 72 ++++++++++++++++++++++++++++++++++++
 plugins/.gitignore           |  2 +
 plugins/Makefile.objs        | 14 +++++++
 plugins/qemu-plugins.symbols | 38 +++++++++++++++++++
 5 files changed, 133 insertions(+)
 create mode 100644 plugins/.gitignore
 create mode 100644 plugins/qemu-plugins.symbols

diff --git a/Makefile b/Makefile
index 15f4745cf3..370eb9ad8d 100644
--- a/Makefile
+++ b/Makefile
@@ -74,6 +74,12 @@ CONFIG_ALL=y
 config-host.mak: $(SRC_PATH)/configure $(SRC_PATH)/pc-bios $(SRC_PATH)/VERSION
 	@echo $@ is out-of-date, running configure
 	@./config.status
+
+# Force configure to re-run if the API symbols are updated
+ifeq ($(CONFIG_PLUGIN),y)
+config-host.mak: $(SRC_PATH)/plugins/qemu-plugins.symbols
+endif
+
 else
 config-host.mak:
 ifneq ($(filter-out $(UNCHECKED_GOALS),$(MAKECMDGOALS)),$(if $(MAKECMDGOALS),,fail))
@@ -730,6 +736,7 @@ distclean: clean
 	rm -f qemu-doc.fn qemu-doc.fns qemu-doc.info qemu-doc.ky qemu-doc.kys
 	rm -f qemu-doc.log qemu-doc.pdf qemu-doc.pg qemu-doc.toc qemu-doc.tp
 	rm -f qemu-doc.vr qemu-doc.txt
+	rm -f qemu-plugins-ld.symbols qemu-plugins-ld64.symbols
 	rm -f config.log
 	rm -f linux-headers/asm
 	rm -f docs/version.texi
diff --git a/configure b/configure
index 485a9837c9..75632b1df1 100755
--- a/configure
+++ b/configure
@@ -30,6 +30,7 @@ TMPO="${TMPDIR1}/${TMPB}.o"
 TMPCXX="${TMPDIR1}/${TMPB}.cxx"
 TMPE="${TMPDIR1}/${TMPB}.exe"
 TMPMO="${TMPDIR1}/${TMPB}.mo"
+TMPTXT="${TMPDIR1}/${TMPB}.txt"
 
 rm -f config.log
 
@@ -5464,6 +5465,61 @@ if compile_prog "" "" ; then
   atomic64=yes
 fi
 
+#########################################
+# See if --dynamic-list is supported by the linker
+ld_dynamic_list="no"
+if test "$static" = "no" ; then
+    cat > $TMPTXT <<EOF
+{
+  foo;
+};
+EOF
+
+    cat > $TMPC <<EOF
+#include <stdio.h>
+void foo(void);
+
+void foo(void)
+{
+  printf("foo\n");
+}
+
+int main(void)
+{
+  foo();
+  return 0;
+}
+EOF
+
+    if compile_prog "" "-Wl,--dynamic-list=$TMPTXT" ; then
+        ld_dynamic_list="yes"
+    fi
+fi
+
+#########################################
+# See if -exported_symbols_list is supported by the linker
+
+ld_exported_symbols_list="no"
+if test "$static" = "no" ; then
+    cat > $TMPTXT <<EOF
+  _foo
+EOF
+
+    if compile_prog "" "-Wl,-exported_symbols_list,$TMPTXT" ; then
+        ld_exported_symbols_list="yes"
+    fi
+fi
+
+if  test "$plugins" = "yes" &&
+    test "$ld_dynamic_list" = "no" &&
+    test "$ld_exported_symbols_list" = "no" ; then
+  error_exit \
+      "Plugin support requires dynamic linking and specifying a set of symbols " \
+      "that are exported to plugins. Unfortunately your linker doesn't " \
+      "support the flag (--dynamic-list or -exported_symbols_list) used " \
+      "for this purpose. You can't build with --static."
+fi
+
 ########################################
 # See if 16-byte vector operations are supported.
 # Even without a vector unit the compiler may expand these.
@@ -7267,6 +7323,22 @@ fi
 if test "$plugins" = "yes" ; then
     echo "CONFIG_PLUGIN=y" >> $config_host_mak
     LIBS="-ldl $LIBS"
+    # Copy the export object list to the build dir
+    if test "$ld_dynamic_list" = "yes" ; then
+	echo "CONFIG_HAS_LD_DYNAMIC_LIST=yes" >> $config_host_mak
+	ld_symbols=qemu-plugins-ld.symbols
+	cp "$source_path/plugins/qemu-plugins.symbols" $ld_symbols
+    elif test "$ld_exported_symbols_list" = "yes" ; then
+	echo "CONFIG_HAS_LD_EXPORTED_SYMBOLS_LIST=yes" >> $config_host_mak
+	ld64_symbols=qemu-plugins-ld64.symbols
+	echo "# Automatically generated by configure - do not modify" > $ld64_symbols
+	grep 'qemu_' "$source_path/plugins/qemu-plugins.symbols" | sed 's/;//g' | \
+	    sed -E 's/^[[:space:]]*(.*)/_\1/' >> $ld64_symbols
+    else
+	error_exit \
+	    "If \$plugins=yes, either \$ld_dynamic_list or " \
+	    "\$ld_exported_symbols_list should have been set to 'yes'."
+    fi
 fi
 
 if test "$tcg_interpreter" = "yes"; then
diff --git a/plugins/.gitignore b/plugins/.gitignore
new file mode 100644
index 0000000000..7b8aaa1f10
--- /dev/null
+++ b/plugins/.gitignore
@@ -0,0 +1,2 @@
+qemu-plugins-ld.symbols
+qemu-plugins-ld64.symbols
diff --git a/plugins/Makefile.objs b/plugins/Makefile.objs
index 95baabf3d2..6f14d91ccb 100644
--- a/plugins/Makefile.objs
+++ b/plugins/Makefile.objs
@@ -5,3 +5,17 @@
 obj-y += loader.o
 obj-y += core.o
 obj-y += api.o
+
+# Abuse -libs suffix to only link with --dynamic-list/-exported_symbols_list
+# when the final binary includes the plugin object.
+#
+# Note that simply setting LDFLAGS is not enough: we build binaries that
+# never link plugin.o, and the linker might fail (at least ld64 does)
+# if the symbols in the list are not in the output binary.
+ifdef CONFIG_HAS_LD_DYNAMIC_LIST
+api.o-libs := -Wl,--dynamic-list=$(BUILD_DIR)/qemu-plugins-ld.symbols
+else
+ifdef CONFIG_HAS_LD_EXPORTED_SYMBOLS_LIST
+api.o-libs := -Wl,-exported_symbols_list,$(BUILD_DIR)/qemu-plugins-ld64.symbols
+endif
+endif
diff --git a/plugins/qemu-plugins.symbols b/plugins/qemu-plugins.symbols
new file mode 100644
index 0000000000..40c0d1abd2
--- /dev/null
+++ b/plugins/qemu-plugins.symbols
@@ -0,0 +1,38 @@
+{
+  qemu_plugin_uninstall;
+  qemu_plugin_reset;
+  qemu_plugin_register_vcpu_init_cb;
+  qemu_plugin_register_vcpu_exit_cb;
+  qemu_plugin_register_vcpu_idle_cb;
+  qemu_plugin_register_vcpu_resume_cb;
+  qemu_plugin_register_vcpu_insn_exec_cb;
+  qemu_plugin_register_vcpu_insn_exec_inline;
+  qemu_plugin_register_vcpu_mem_cb;
+  qemu_plugin_register_vcpu_mem_haddr_cb;
+  qemu_plugin_register_vcpu_mem_inline;
+  qemu_plugin_ram_addr_from_host;
+  qemu_plugin_register_vcpu_tb_trans_cb;
+  qemu_plugin_register_vcpu_tb_exec_cb;
+  qemu_plugin_register_vcpu_tb_exec_inline;
+  qemu_plugin_register_flush_cb;
+  qemu_plugin_register_vcpu_syscall_cb;
+  qemu_plugin_register_vcpu_syscall_ret_cb;
+  qemu_plugin_register_atexit_cb;
+  qemu_plugin_tb_n_insns;
+  qemu_plugin_tb_get_insn;
+  qemu_plugin_tb_vaddr;
+  qemu_plugin_insn_data;
+  qemu_plugin_insn_size;
+  qemu_plugin_insn_vaddr;
+  qemu_plugin_insn_haddr;
+  qemu_plugin_mem_size_shift;
+  qemu_plugin_mem_is_sign_extended;
+  qemu_plugin_mem_is_big_endian;
+  qemu_plugin_mem_is_store;
+  qemu_plugin_get_hwaddr;
+  qemu_plugin_hwaddr_is_io;
+  qemu_plugin_hwaddr_to_raddr;
+  qemu_plugin_vcpu_for_each;
+  qemu_plugin_n_vcpus;
+  qemu_plugin_n_max_vcpus;
+};
-- 
2.20.1