simpleperf: fix symbolization in multi-executable-segments libraries.

Apps may run with libraries with multiple executable segments.
Symbolization ip addresses in these libraries need to use map.pgoff.

The old formula converting ip to vaddr_in_file:
  vaddr_in_file = ip - map.start + min_executable_vaddr

The new formula converting ip to vaddr_in_file:
  offset_in_file = ip - map.start + map.pgoff
  vaddr_in_file = offset_in_file - file_offset_of_min_executable_vaddr
		  + min_executable_vaddr

Bug: 124056476
Test: run simpleperf_unit_test.
Test: use simpleperf to profile facebook app, ip addresses hitting libc.so
Test: and libart.so are symbolized correctly.
Change-Id: I5fd3ed822a916c4d04a9868d6d209c43ee190c5b

1 files changed, 13 insertions, 2 deletions

diff --git a/simpleperf/read_elf_test.cpp b/simpleperf/read_elf_test.cpp
index 55a9cde9..f51244e7 100644
--- a/simpleperf/read_elf_test.cpp
+++ b/simpleperf/read_elf_test.cpp
@@ -162,7 +162,18 @@ TEST(read_elf, read_elf_with_broken_section_table) {
   BuildId build_id;
   ASSERT_EQ(ElfStatus::NO_BUILD_ID, GetBuildIdFromElfFile(elf_path, &build_id));
   uint64_t min_vaddr;
-  ASSERT_EQ(ElfStatus::NO_ERROR, ReadMinExecutableVirtualAddressFromElfFile(elf_path, BuildId(),
-                                                                            &min_vaddr));
+  uint64_t file_offset_of_min_vaddr;
+  ASSERT_EQ(ElfStatus::NO_ERROR, ReadMinExecutableVirtualAddressFromElfFile(
+      elf_path, BuildId(), &min_vaddr, &file_offset_of_min_vaddr));
   ASSERT_EQ(min_vaddr, 0u);
+  ASSERT_EQ(file_offset_of_min_vaddr, 0u);
+}
+
+TEST(read_elf, ReadMinExecutableVirtualAddressFromElfFile) {
+  uint64_t min_vaddr;
+  uint64_t file_offset_of_min_vaddr;
+  ASSERT_EQ(ElfStatus::NO_ERROR, ReadMinExecutableVirtualAddressFromElfFile(
+      GetTestData("libc.so"), BuildId(), &min_vaddr, &file_offset_of_min_vaddr));
+  ASSERT_EQ(min_vaddr, 0x29000u);
+  ASSERT_EQ(file_offset_of_min_vaddr, 0x29000u);
 }