Handle ARM thumb function symbols.

ARM thumb functions will have the zero bit set to one, which can cause
function name lookups to fail.

Add an ARM special GetFunctionName that handles this condition.

Fix a couple of the function offsets in unit tests.

Bug: 74844137

Test: Ran unit tests.
Test: Ran debuggerd -b on processes on a bullhead device.
Change-Id: Ibd407db34eaaa641f91fdb4f589c44a0dcc0216a
(cherry picked from commit 704ec9adbac6f7f265afe0d727e685b92f7726d0)

4 files changed, 19 insertions, 4 deletions

diff --git a/libunwindstack/ElfInterfaceArm.cpp b/libunwindstack/ElfInterfaceArm.cpp
index dfb8e8f..a5afc7e 100644
--- a/libunwindstack/ElfInterfaceArm.cpp
+++ b/libunwindstack/ElfInterfaceArm.cpp
@@ -171,4 +171,17 @@ bool ElfInterfaceArm::StepExidx(uint64_t pc, uint64_t load_bias, Regs* regs, Mem
   return return_value;
 }
 
+bool ElfInterfaceArm::GetFunctionName(uint64_t addr, uint64_t load_bias, std::string* name,
+                                      uint64_t* offset) {
+  // For ARM, thumb function symbols have bit 0 set, but the address passed
+  // in here might not have this bit set and result in a failure to find
+  // the thumb function names. Adjust the address and offset to account
+  // for this possible case.
+  if (ElfInterface32::GetFunctionName(addr | 1, load_bias, name, offset)) {
+    *offset &= ~1;
+    return true;
+  }
+  return false;
+}
+
 }  // namespace unwindstack
diff --git a/libunwindstack/ElfInterfaceArm.h b/libunwindstack/ElfInterfaceArm.h
index 9c067ba..c1597ce 100644
--- a/libunwindstack/ElfInterfaceArm.h
+++ b/libunwindstack/ElfInterfaceArm.h
@@ -76,6 +76,9 @@ class ElfInterfaceArm : public ElfInterface32 {
   bool StepExidx(uint64_t pc, uint64_t load_bias, Regs* regs, Memory* process_memory,
                  bool* finished);
 
+  bool GetFunctionName(uint64_t addr, uint64_t load_bias, std::string* name,
+                       uint64_t* offset) override;
+
   uint64_t start_offset() { return start_offset_; }
 
   size_t total_entries() { return total_entries_; }
diff --git a/libunwindstack/tests/UnwindOfflineTest.cpp b/libunwindstack/tests/UnwindOfflineTest.cpp
index af4a5b5..515bc8c 100644
--- a/libunwindstack/tests/UnwindOfflineTest.cpp
+++ b/libunwindstack/tests/UnwindOfflineTest.cpp
@@ -188,7 +188,7 @@ TEST_F(UnwindOfflineTest, pc_straddle_arm) {
   std::string frame_info(DumpFrames(unwinder));
   ASSERT_EQ(4U, unwinder.NumFrames()) << "Unwind:\n" << frame_info;
   EXPECT_EQ(
-      "  #00 pc 0001a9f8  libc.so (abort+63)\n"
+      "  #00 pc 0001a9f8  libc.so (abort+64)\n"
       "  #01 pc 00006a1b  libbase.so (_ZN7android4base14DefaultAborterEPKc+6)\n"
       "  #02 pc 00007441  libbase.so (_ZN7android4base10LogMessageD2Ev+748)\n"
       "  #03 pc 00015147  /does/not/exist/libhidlbase.so\n",
@@ -575,7 +575,7 @@ TEST_F(UnwindOfflineTest, jit_debug_arm) {
   std::string frame_info(DumpFrames(unwinder));
   ASSERT_EQ(76U, unwinder.NumFrames()) << "Unwind:\n" << frame_info;
   EXPECT_EQ(
-      "  #00 pc 00018a5e  libarttestd.so (Java_Main_unwindInProcess+865)\n"
+      "  #00 pc 00018a5e  libarttestd.so (Java_Main_unwindInProcess+866)\n"
       "  #01 pc 0000212d (offset 0x2000)  137-cfi.odex (boolean Main.unwindInProcess(boolean, int, "
       "boolean)+92)\n"
       "  #02 pc 00011cb1  anonymous:e2796000 (boolean Main.bar(boolean)+72)\n"
diff --git a/libunwindstack/tools/unwind_info.cpp b/libunwindstack/tools/unwind_info.cpp
index a0abcca..5a8edfd 100644
--- a/libunwindstack/tools/unwind_info.cpp
+++ b/libunwindstack/tools/unwind_info.cpp
@@ -53,8 +53,7 @@ void DumpArm(ElfInterfaceArm* interface) {
       printf("  PC 0x%" PRIx64, addr + load_bias);
       uint64_t func_offset;
       uint64_t pc = addr + load_bias;
-      // This might be a thumb function, so set the low bit.
-      if (interface->GetFunctionName(pc | 1, load_bias, &name, &func_offset) && !name.empty()) {
+      if (interface->GetFunctionName(pc, load_bias, &name, &func_offset) && !name.empty()) {
         printf(" <%s>", name.c_str());
       }
       printf("\n");