Build correctly on old kernels without precise_ip support

Update Makefile to autodetect kernel features, such as precise_ip. Also,
try to autodetect which header file to use for perf_event.

Author: andysan

Makefile

@@ -2,7 +2,28 @@ CC=gcc
 LD=gcc
 KERNEL_RELEASE=$(shell uname -r)
 KERNEL_SRC=/lib/modules/$(KERNEL_RELEASE)/source
-CFLAGS=-g -Wall -std=gnu99 -DPERFH=\"$(KERNEL_SRC)/include/linux/perf_event.h\"
+
+# Check if perf_event there is a perf_event.h available in the source
+# of the running kernel. In that case, assume that it's newer and use
+# that.
+ifneq ($(wildcard $(KERNEL_SRC)/include/linux/perf_event.h),)
+  PERF_EVENT_H=$(KERNEL_SRC)/include/linux/perf_event.h
+  CONFIG+=-DPERFH=\"$(PERF_EVENT_H)\"
+else
+  PERF_EVENT_H=/usr/include/linux/perf_event.h
+endif
+
+ifeq ($(wildcard $(PERF_EVENT_H)),)
+  $(error "Can't find a usable perf_event header file")
+endif
+
+# Check if the header file has support for the precise_ip option. This
+# is not the case for old header files.
+ifneq ($(shell grep '^[[:space:]]*precise_ip' $(PERF_EVENT_H) 2>/dev/null),)
+CONFIG+=-DHAVE_PRECISE_IP
+endif
+
+CFLAGS=-g -Wall -std=gnu99 $(CONFIG)
 
 
 all: rawperf perfrecord perfdump

perf_argp.c

@@ -99,7 +99,9 @@ struct perf_event_attr perf_base_attr = {
     .enable_on_exec = 0,
     .task = 0,
     .watermark = 0,
+#ifdef HAVE_PRECISE_IP
     .precise_ip = 0,
+#endif
 };
 
 ctr_list_t perf_ctrs = { NULL, NULL };
@@ -109,7 +111,9 @@ enum {
     KEY_EXCLUSIVE = -2,
     KEY_SAMPLE_PERIOD = -3,
     KEY_SAMPLE_FREQ = -4,
+#ifdef HAVE_PRECISE_IP
     KEY_PRECISE_IP = -5,
+#endif
 };
 
 static struct argp_option options[] = {
@@ -124,7 +128,9 @@ static struct argp_option options[] = {
       "Use raw performance event EVENT (creates a new event)", 0 },
     { "sample-period", KEY_SAMPLE_PERIOD, "N", 0, "Use sample period N", 2 },
     { "sample-freq", KEY_SAMPLE_FREQ, "N", 0, "Use sample frequency N", 2 },
+#ifdef HAVE_PRECISE_IP
     { "precise-ip", KEY_PRECISE_IP, "N", 0, "Set the precise_ip field to N", 2 },
+#endif
     { 0 }
 };
 
@@ -372,10 +378,12 @@ parse_opt(int key, char *arg, struct argp_state *state)
         current_attr->freq = 1;
         break;
 
+#ifdef HAVE_PRECISE_IP
     case KEY_PRECISE_IP:
         current_attr->precise_ip =
             perf_argp_parse_long("precise ip", arg, state);
         break;
+#endif
 
     case ARGP_KEY_END:
         if (!perf_ctrs.head) {