qemu-log: new option -dfilter to limit output

When debugging big programs or system emulation sometimes you want both
the verbosity of cpu,exec et all but don't want to generate lots of logs
for unneeded stuff. This patch adds a new option -dfilter which allows
you to specify interesting address ranges in the form:

  -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,...

Then logging code can use the new qemu_log_in_addr_range() function to
decide if it will output logging information for the given range.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <1458052224-9316-7-git-send-email-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/util/log.c b/util/log.c
index 4e69586a73..671b6174e4 100644
--- a/util/log.c
+++ b/util/log.c
@@ -20,12 +20,16 @@
 #include "qemu/osdep.h"
 #include "qemu-common.h"
 #include "qemu/log.h"
+#include "qemu/range.h"
+#include "qemu/error-report.h"
+#include "qemu/cutils.h"
 #include "trace/control.h"
 
 static char *logfilename;
 FILE *qemu_logfile;
 int qemu_loglevel;
 static int log_append = 0;
+static GArray *debug_regions;
 
 void qemu_log(const char *fmt, ...)
 {
@@ -94,6 +98,89 @@ void qemu_set_log_filename(const char *filename)
     qemu_set_log(qemu_loglevel);
 }
 
+/* Returns true if addr is in our debug filter or no filter defined
+ */
+bool qemu_log_in_addr_range(uint64_t addr)
+{
+    if (debug_regions) {
+        int i = 0;
+        for (i = 0; i < debug_regions->len; i++) {
+            struct Range *range = &g_array_index(debug_regions, Range, i);
+            if (addr >= range->begin && addr <= range->end) {
+                return true;
+            }
+        }
+        return false;
+    } else {
+        return true;
+    }
+}
+
+
+void qemu_set_dfilter_ranges(const char *filter_spec)
+{
+    gchar **ranges = g_strsplit(filter_spec, ",", 0);
+    if (ranges) {
+        gchar **next = ranges;
+        gchar *r = *next++;
+        debug_regions = g_array_sized_new(FALSE, FALSE,
+                                          sizeof(Range), g_strv_length(ranges));
+        while (r) {
+            char *range_op = strstr(r, "-");
+            char *r2 = range_op ? range_op + 1 : NULL;
+            if (!range_op) {
+                range_op = strstr(r, "+");
+                r2 = range_op ? range_op + 1 : NULL;
+            }
+            if (!range_op) {
+                range_op = strstr(r, "..");
+                r2 = range_op ? range_op + 2 : NULL;
+            }
+            if (range_op) {
+                const char *e = NULL;
+                uint64_t r1val, r2val;
+
+                if ((qemu_strtoull(r, &e, 0, &r1val) == 0) &&
+                    (qemu_strtoull(r2, NULL, 0, &r2val) == 0) &&
+                    r2val > 0) {
+                    struct Range range;
+
+                    g_assert(e == range_op);
+
+                    switch (*range_op) {
+                    case '+':
+                    {
+                        range.begin = r1val;
+                        range.end = r1val + (r2val - 1);
+                        break;
+                    }
+                    case '-':
+                    {
+                        range.end = r1val;
+                        range.begin = r1val - (r2val - 1);
+                        break;
+                    }
+                    case '.':
+                        range.begin = r1val;
+                        range.end = r2val;
+                        break;
+                    default:
+                        g_assert_not_reached();
+                    }
+                    g_array_append_val(debug_regions, range);
+
+                } else {
+                    g_error("Failed to parse range in: %s", r);
+                }
+            } else {
+                g_error("Bad range specifier in: %s", r);
+            }
+            r = *next++;
+        }
+        g_strfreev(ranges);
+    }
+}
+
 const QEMULogItem qemu_log_items[] = {
     { CPU_LOG_TB_OUT_ASM, "out_asm",
       "show generated host assembly code for each compiled TB" },