Display the map offset for each frame.
The dlopen of a shared library in an apk results in large map offsets.
Unfortunately, the current way that the frame data is printed, it's
impossible to tell what the relative pc is relative to. With the
addition of the offset, it's possible to figure out what the relative
pc actually references.
Bug: 23348999
(cherry picked from commit e0ab23223a1c3110c9550136b8a119b4c30ec066)
Change-Id: I950f92c1cb29ee05eed777f47453efa03318cf3e
diff --git a/libbacktrace/Backtrace.cpp b/libbacktrace/Backtrace.cpp
index 128bb04..97f0ef4 100644
--- a/libbacktrace/Backtrace.cpp
+++ b/libbacktrace/Backtrace.cpp
@@ -102,6 +102,11 @@
uintptr_t relative_pc = BacktraceMap::GetRelativePc(frame->map, frame->pc);
std::string line(StringPrintf("#%02zu pc %" PRIPTR " %s", frame->num, relative_pc, map_name));
+ // Special handling for non-zero offset maps, we need to print that
+ // information.
+ if (frame->map.offset != 0) {
+ line += " (offset " + StringPrintf("0x%" PRIxPTR, frame->map.offset) + ")";
+ }
if (!frame->func_name.empty()) {
line += " (" + frame->func_name;
if (frame->func_offset) {
diff --git a/libbacktrace/backtrace_test.cpp b/libbacktrace/backtrace_test.cpp
index 6bd7529..9ebd639 100644
--- a/libbacktrace/backtrace_test.cpp
+++ b/libbacktrace/backtrace_test.cpp
@@ -825,6 +825,15 @@
EXPECT_EQ("#01 pc 123456dc MapFake (ProcFake+645)",
#endif
backtrace->FormatFrameData(&frame));
+
+ // Check a non-zero map offset.
+ frame.map.offset = 0x1000;
+#if defined(__LP64__)
+ EXPECT_EQ("#01 pc 00000000123456dc MapFake (offset 0x1000) (ProcFake+645)",
+#else
+ EXPECT_EQ("#01 pc 123456dc MapFake (offset 0x1000) (ProcFake+645)",
+#endif
+ backtrace->FormatFrameData(&frame));
}
struct map_test_t {