Add load base to map for relocation packing.

The new linker relocation packing support uses non-zero load bases,
so we better handle them properly.

Also print out the load base for a map if it's non-zero.

Bug: 20687795
Change-Id: Iec2d1db2051e7b4a278c1dfa57d745128a7f2974

3 files changed, 14 insertions, 6 deletions

diff --git a/libbacktrace/Backtrace.cpp b/libbacktrace/Backtrace.cpp
index 91ca8b7..d75c210 100644
--- a/libbacktrace/Backtrace.cpp
+++ b/libbacktrace/Backtrace.cpp
@@ -97,12 +97,7 @@ std::string Backtrace::FormatFrameData(const backtrace_frame_data_t* frame) {
     map_name = "<unknown>";
   }
 
-  uintptr_t relative_pc;
-  if (BacktraceMap::IsValid(frame->map)) {
-    relative_pc = frame->pc - frame->map.start;
-  } else {
-    relative_pc = frame->pc;
-  }
+  uintptr_t relative_pc = BacktraceMap::GetRelativePc(frame->map, frame->pc);
 
   std::string line(StringPrintf("#%02zu pc %" PRIPTR "  %s", frame->num, relative_pc, map_name));
   if (!frame->func_name.empty()) {
diff --git a/libbacktrace/UnwindMap.cpp b/libbacktrace/UnwindMap.cpp
index fa59d07..4a4e2f3 100644
--- a/libbacktrace/UnwindMap.cpp
+++ b/libbacktrace/UnwindMap.cpp
@@ -51,6 +51,7 @@ bool UnwindMap::GenerateMap() {
 
     map.start = unw_map.start;
     map.end = unw_map.end;
+    map.load_base = unw_map.load_base;
     map.flags = unw_map.flags;
     map.name = unw_map.path;
 
@@ -91,6 +92,7 @@ bool UnwindMapLocal::GenerateMap() {
 
       map.start = unw_map.start;
       map.end = unw_map.end;
+      map.load_base = unw_map.load_base;
       map.flags = unw_map.flags;
       map.name = unw_map.path;
 
diff --git a/libbacktrace/backtrace_test.cpp b/libbacktrace/backtrace_test.cpp
index 4af6592..ebcb1f8 100644
--- a/libbacktrace/backtrace_test.cpp
+++ b/libbacktrace/backtrace_test.cpp
@@ -771,6 +771,7 @@ TEST(libbacktrace, format_test) {
   // Check map name empty, but exists.
   frame.map.start = 1;
   frame.map.end = 1;
+  frame.map.load_base = 0;
 #if defined(__LP64__)
   EXPECT_EQ("#01 pc 0000000000000001  <unknown>",
 #else
@@ -808,6 +809,16 @@ TEST(libbacktrace, format_test) {
   EXPECT_EQ("#01 pc 12345678  MapFake (ProcFake+645)",
 #endif
             backtrace->FormatFrameData(&frame));
+
+  // Check func_name is set, func offset is non-zero, and load_base is non-zero.
+  frame.func_offset = 645;
+  frame.map.load_base = 100;
+#if defined(__LP64__)
+  EXPECT_EQ("#01 pc 00000000123456dc  MapFake (ProcFake+645)",
+#else
+  EXPECT_EQ("#01 pc 123456dc  MapFake (ProcFake+645)",
+#endif
+            backtrace->FormatFrameData(&frame));
 }
 
 struct map_test_t {