Remove overly restrictive check for memory.

Remove unit test that is not needed any more.

Slightly reorganize the code around the changed check.

Bug: 77958880

Test: Ran backtrace tests with new linker options.
Test: Ran libunwindstack unit tests.
Change-Id: Ie95707323fb51616a093cafb83e0343fa24e7e61

2 files changed, 11 insertions, 36 deletions

diff --git a/libunwindstack/MapInfo.cpp b/libunwindstack/MapInfo.cpp
index fe32b5e..e3b48ca 100644
--- a/libunwindstack/MapInfo.cpp
+++ b/libunwindstack/MapInfo.cpp
@@ -96,11 +96,6 @@ Memory* MapInfo::CreateMemory(const std::shared_ptr<Memory>& process_memory) {
     }
   }
 
-  // If the map isn't readable, don't bother trying to read from process memory.
-  if (!(flags & PROT_READ)) {
-    return nullptr;
-  }
-
   // Need to verify that this elf is valid. It's possible that
   // only part of the elf file to be mapped into memory is in the executable
   // map. In this case, there will be another read-only map that includes the
@@ -132,18 +127,19 @@ Memory* MapInfo::CreateMemory(const std::shared_ptr<Memory>& process_memory) {
     }
   }
 
-  if (ro_map_info != nullptr) {
-    // Make sure that relative pc values are corrected properly.
-    elf_offset = offset - closest_offset;
+  if (ro_map_info == nullptr) {
+    return nullptr;
+  }
 
-    MemoryRanges* ranges = new MemoryRanges;
-    ranges->Insert(new MemoryRange(process_memory, ro_map_info->start,
-                                   ro_map_info->end - ro_map_info->start, 0));
-    ranges->Insert(new MemoryRange(process_memory, start, end - start, elf_offset));
+  // Make sure that relative pc values are corrected properly.
+  elf_offset = offset - closest_offset;
 
-    return ranges;
-  }
-  return nullptr;
+  MemoryRanges* ranges = new MemoryRanges;
+  ranges->Insert(new MemoryRange(process_memory, ro_map_info->start,
+                                 ro_map_info->end - ro_map_info->start, 0));
+  ranges->Insert(new MemoryRange(process_memory, start, end - start, elf_offset));
+
+  return ranges;
 }
 
 Elf* MapInfo::GetElf(const std::shared_ptr<Memory>& process_memory, ArchEnum expected_arch) {
diff --git a/libunwindstack/tests/MapInfoGetElfTest.cpp b/libunwindstack/tests/MapInfoGetElfTest.cpp
index f3b4679..99f8fa3 100644
--- a/libunwindstack/tests/MapInfoGetElfTest.cpp
+++ b/libunwindstack/tests/MapInfoGetElfTest.cpp
@@ -290,27 +290,6 @@ TEST_F(MapInfoGetElfTest, file_backed_non_zero_offset_partial_file_whole_elf64)
   ASSERT_TRUE(elf->memory()->ReadFully(0x1000, buffer.data(), 1));
 }
 
-TEST_F(MapInfoGetElfTest, process_memory_not_read_only) {
-  MapInfo info(nullptr, 0x9000, 0xa000, 0x1000, 0, "");
-
-  // Create valid elf data in process memory only.
-  Elf64_Ehdr ehdr;
-  TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, EM_AARCH64);
-  ehdr.e_shoff = 0x2000;
-  ehdr.e_shentsize = sizeof(Elf64_Shdr) + 100;
-  ehdr.e_shnum = 0;
-  memory_->SetMemory(0x9000, &ehdr, sizeof(ehdr));
-
-  Elf* elf = info.GetElf(process_memory_, ARCH_ARM64);
-  ASSERT_TRUE(elf != nullptr);
-  ASSERT_FALSE(elf->valid());
-
-  info.elf.reset();
-  info.flags = PROT_READ;
-  elf = info.GetElf(process_memory_, ARCH_ARM64);
-  ASSERT_TRUE(elf->valid());
-}
-
 TEST_F(MapInfoGetElfTest, check_device_maps) {
   MapInfo info(nullptr, 0x7000, 0x8000, 0x1000, PROT_READ | MAPS_FLAGS_DEVICE_MAP,
                "/dev/something");