Implement support for linker rosegment option.

The rosegment linker option results in two maps containing the elf data
existing. One is an execute map where the code lives, and the other is the
read-only segment which contains the elf header information. If the file
backing a shared library in memory is not readable, then the new code
will attempt to find the read-only map that has the same name as the
current execute segment, and that is at offest zero in the file.

Add new unit tests for this functionality.

Add the missing MapInfoCreateMemoryTest.cpp to the list of tests.

Bug: 109657296

Test: Pass new unit tests.
Test: All unit libbacktrace/libunwindstack tests pass with rosegment enabled.
Change-Id: If8f69e4a067d77b3f2a7c31e2e5cd989a0702a8c

1 files changed, 12 insertions, 0 deletions

diff --git a/libunwindstack/Memory.cpp b/libunwindstack/Memory.cpp
index beb2aade8..cfa8c6d93 100644
--- a/libunwindstack/Memory.cpp
+++ b/libunwindstack/Memory.cpp
@@ -316,6 +316,18 @@ size_t MemoryRange::Read(uint64_t addr, void* dst, size_t size) {
   return memory_->Read(read_addr, dst, read_length);
 }
 
+void MemoryRanges::Insert(MemoryRange* memory) {
+  maps_.emplace(memory->offset() + memory->length(), memory);
+}
+
+size_t MemoryRanges::Read(uint64_t addr, void* dst, size_t size) {
+  auto entry = maps_.upper_bound(addr);
+  if (entry != maps_.end()) {
+    return entry->second->Read(addr, dst, size);
+  }
+  return 0;
+}
+
 bool MemoryOffline::Init(const std::string& file, uint64_t offset) {
   auto memory_file = std::make_shared<MemoryFileAtOffset>();
   if (!memory_file->Init(file, offset)) {