[PATCH v8 13/14] perf callchain: Support x86 target platform

[He Kuang]

Support x86(32-bit) cross platform callchain unwind.

Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
---
 tools/perf/arch/x86/util/unwind-libunwind.c |  6 +++--
 tools/perf/config/Makefile                  |  8 +++++++
 tools/perf/util/Build                       |  1 +
 tools/perf/util/libunwind/x86_32.c          | 37 +++++++++++++++++++++++++++++
 tools/perf/util/unwind-libunwind.c          | 14 +++++++++--
 5 files changed, 62 insertions(+), 4 deletions(-)
 create mode 100644 tools/perf/util/libunwind/x86_32.c

diff --git a/tools/perf/arch/x86/util/unwind-libunwind.c b/tools/perf/arch/x86/util/unwind-libunwind.c
index db25e93..4f16661 100644
--- a/tools/perf/arch/x86/util/unwind-libunwind.c
+++ b/tools/perf/arch/x86/util/unwind-libunwind.c
@@ -1,12 +1,14 @@
 
+#ifndef REMOTE_UNWIND_LIBUNWIND
 #include <errno.h>
 #include <libunwind.h>
 #include "perf_regs.h"
 #include "../../util/unwind.h"
 #include "../../util/debug.h"
+#endif
 
 #ifdef HAVE_ARCH_X86_64_SUPPORT
-int libunwind__arch_reg_id(int regnum)
+int LIBUNWIND__ARCH_REG_ID(int regnum)
 {
 	int id;
 
@@ -70,7 +72,7 @@ int libunwind__arch_reg_id(int regnum)
 	return id;
 }
 #else
-int libunwind__arch_reg_id(int regnum)
+int LIBUNWIND__ARCH_REG_ID(int regnum)
 {
 	int id;
 
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index 3918687..34999fb 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -354,6 +354,14 @@ endif
 
 ifndef NO_LIBUNWIND
   have_libunwind :=
+
+  ifeq ($(feature-libunwind-x86), 1)
+    $(call detected,CONFIG_LIBUNWIND_X86)
+    CFLAGS += -DHAVE_LIBUNWIND_X86_SUPPORT
+    LDFLAGS += -lunwind-x86
+    have_libunwind = 1
+  endif
+
   ifneq ($(feature-libunwind), 1)
     msg := $(warning No libunwind found. Please install libunwind-dev[el] >= 1.1 and/or set LIBUNWIND_DIR);
     NO_LOCAL_LIBUNWIND := 1
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 004fb1d..7746e09 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -101,6 +101,7 @@ libperf-$(CONFIG_DWARF) += dwarf-aux.o
 libperf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
 libperf-$(CONFIG_LOCAL_LIBUNWIND)    += unwind-libunwind-local.o
 libperf-$(CONFIG_LIBUNWIND)          += unwind-libunwind.o
+libperf-$(CONFIG_LIBUNWIND_X86)      += libunwind/x86_32.o
 
 libperf-$(CONFIG_LIBBABELTRACE) += data-convert-bt.o
 
diff --git a/tools/perf/util/libunwind/x86_32.c b/tools/perf/util/libunwind/x86_32.c
new file mode 100644
index 0000000..d98c17e
--- /dev/null
+++ b/tools/perf/util/libunwind/x86_32.c
@@ -0,0 +1,37 @@
+/*
+ * This file setups defines to compile arch specific binary from the
+ * generic one.
+ *
+ * The function 'LIBUNWIND__ARCH_REG_ID' name is set according to arch
+ * name and the defination of this function is included directly from
+ * 'arch/x86/util/unwind-libunwind.c', to make sure that this function
+ * is defined no matter what arch the host is.
+ *
+ * Finally, the arch specific unwind methods are exported which will
+ * be assigned to each x86 thread.
+ */
+
+#define REMOTE_UNWIND_LIBUNWIND
+#define LIBUNWIND__ARCH_REG_ID(regnum) libunwind__x86_reg_id(regnum)
+
+#include "unwind.h"
+#include "debug.h"
+#include "libunwind-x86.h"
+#include <../../../../arch/x86/include/uapi/asm/perf_regs.h>
+
+/* HAVE_ARCH_X86_64_SUPPORT is used in'arch/x86/util/unwind-libunwind.c'
+ * for x86_32, we undef it to compile code for x86_32 only.
+ */
+#undef HAVE_ARCH_X86_64_SUPPORT
+#include "../../arch/x86/util/unwind-libunwind.c"
+
+/* Explicitly define NO_LIBUNWIND_DEBUG_FRAME, because non-ARM has no
+ * dwarf_find_debug_frame() function.
+ */
+#ifndef NO_LIBUNWIND_DEBUG_FRAME
+#define NO_LIBUNWIND_DEBUG_FRAME
+#endif
+#include "util/unwind-libunwind-local.c"
+
+struct unwind_libunwind_ops *
+x86_32_unwind_libunwind_ops = &_unwind_libunwind_ops;
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index 8e87884..28f8a4d 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -5,6 +5,7 @@
 #include "arch/common.h"
 
 struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
+struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
 
 void unwind__register_ops(struct thread *thread,
 			  struct unwind_libunwind_ops *ops)
@@ -16,6 +17,7 @@ int unwind__prepare_access(struct thread *thread, struct map *map)
 {
 	const char *arch;
 	enum dso_type dso_type;
+	struct unwind_libunwind_ops *ops = local_unwind_libunwind_ops;
 
 	if (thread->addr_space) {
 		pr_debug("unwind: thread map already set, dso=%s\n",
@@ -31,9 +33,17 @@ int unwind__prepare_access(struct thread *thread, struct map *map)
 		return 0;
 
 	arch = normalize_arch(thread->mg->machine->env->arch);
-	pr_debug("unwind: target platform=%s\n", arch);
 
-	unwind__register_ops(thread, local_unwind_libunwind_ops);
+	if (!strcmp(arch, "x86"))
+		if (dso_type != DSO__TYPE_64BIT)
+			ops = x86_32_unwind_libunwind_ops;
+
+	if (!ops) {
+		pr_err("unwind: target platform=%s is not supported\n", arch);
+		return -1;
+	}
+
+	unwind__register_ops(thread, ops);
 
 	return thread->unwind_libunwind_ops->prepare_access(thread);
 }
-- 
1.8.5.2