1 files changed, 93 insertions, 40 deletions

diff --git a/libunwindstack/tools/unwind.cpp b/libunwindstack/tools/unwind.cpp
index 3614198eb..faac2eff6 100644
--- a/libunwindstack/tools/unwind.cpp
+++ b/libunwindstack/tools/unwind.cpp
@@ -26,7 +26,11 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <memory>
 #include <string>
+#include <vector>
+
+#include <android-base/stringprintf.h>
 
 #include <unwindstack/Elf.h>
 #include <unwindstack/MapInfo.h>
@@ -55,6 +59,62 @@ static bool Detach(pid_t pid) {
   return ptrace(PTRACE_DETACH, pid, 0, 0) == 0;
 }
 
+std::string GetFrameInfo(size_t frame_num, unwindstack::Regs* regs,
+                         const std::shared_ptr<unwindstack::Memory>& process_memory,
+                         unwindstack::MapInfo* map_info, uint64_t* rel_pc) {
+  bool bits32;
+  switch (regs->MachineType()) {
+    case EM_ARM:
+    case EM_386:
+      bits32 = true;
+      break;
+
+    default:
+      bits32 = false;
+  }
+
+  if (map_info == nullptr) {
+    if (bits32) {
+      return android::base::StringPrintf("  #%02zu pc %08" PRIx64, frame_num, regs->pc());
+    } else {
+      return android::base::StringPrintf("  #%02zu pc %016" PRIx64, frame_num, regs->pc());
+    }
+  }
+
+  unwindstack::Elf* elf = map_info->GetElf(process_memory, true);
+  *rel_pc = elf->GetRelPc(regs->pc(), map_info);
+  uint64_t adjusted_rel_pc = *rel_pc;
+  // Don't need to adjust the first frame pc.
+  if (frame_num != 0) {
+    adjusted_rel_pc = regs->GetAdjustedPc(*rel_pc, elf);
+  }
+
+  std::string line;
+  if (bits32) {
+    line = android::base::StringPrintf("  #%02zu pc %08" PRIx64, frame_num, adjusted_rel_pc);
+  } else {
+    line = android::base::StringPrintf("  #%02zu pc %016" PRIx64, frame_num, adjusted_rel_pc);
+  }
+  if (!map_info->name.empty()) {
+    line += "  " + map_info->name;
+    if (map_info->elf_offset != 0) {
+      line += android::base::StringPrintf(" (offset 0x%" PRIx64 ")", map_info->elf_offset);
+    }
+  } else {
+    line += android::base::StringPrintf("  <anonymous:%" PRIx64 ">", map_info->offset);
+  }
+  uint64_t func_offset;
+  std::string func_name;
+  if (elf->GetFunctionName(adjusted_rel_pc, &func_name, &func_offset)) {
+    line += " (" + func_name;
+    if (func_offset != 0) {
+      line += android::base::StringPrintf("+%" PRId64, func_offset);
+    }
+    line += ')';
+  }
+  return line;
+}
+
 void DoUnwind(pid_t pid) {
   unwindstack::RemoteMaps remote_maps(pid);
   if (!remote_maps.Parse()) {
@@ -68,7 +128,6 @@ void DoUnwind(pid_t pid) {
     return;
   }
 
-  bool bits32 = true;
   printf("ABI: ");
   switch (regs->MachineType()) {
     case EM_ARM:
@@ -79,11 +138,9 @@ void DoUnwind(pid_t pid) {
       break;
     case EM_AARCH64:
       printf("arm64");
-      bits32 = false;
       break;
     case EM_X86_64:
       printf("x86_64");
-      bits32 = false;
       break;
     default:
       printf("unknown\n");
@@ -92,52 +149,48 @@ void DoUnwind(pid_t pid) {
   printf("\n");
 
   auto process_memory = unwindstack::Memory::CreateProcessMemory(pid);
+  bool return_address_attempt = false;
+  std::vector<std::string> frames;
   for (size_t frame_num = 0; frame_num < 64; frame_num++) {
-    if (regs->pc() == 0) {
-      break;
-    }
     unwindstack::MapInfo* map_info = remote_maps.Find(regs->pc());
+    uint64_t rel_pc;
+    frames.push_back(GetFrameInfo(frame_num, regs, process_memory, map_info, &rel_pc));
+    bool stepped;
     if (map_info == nullptr) {
-      printf("Failed to find map data for the pc\n");
-      break;
-    }
-
-    unwindstack::Elf* elf = map_info->GetElf(process_memory, true);
-
-    uint64_t rel_pc = elf->GetRelPc(regs->pc(), map_info);
-    uint64_t adjusted_rel_pc = rel_pc;
-    // Don't need to adjust the first frame pc.
-    if (frame_num != 0) {
-      adjusted_rel_pc = regs->GetAdjustedPc(rel_pc, elf);
-    }
-
-    std::string name;
-    if (bits32) {
-      printf("  #%02zu pc %08" PRIx64, frame_num, adjusted_rel_pc);
+      stepped = false;
     } else {
-      printf("  #%02zu pc %016" PRIx64, frame_num, adjusted_rel_pc);
-    }
-    if (!map_info->name.empty()) {
-      printf("  %s", map_info->name.c_str());
-      if (map_info->elf_offset != 0) {
-        printf(" (offset 0x%" PRIx64 ")", map_info->elf_offset);
+      bool finished;
+      stepped =
+          map_info->elf->Step(rel_pc + map_info->elf_offset, regs, process_memory.get(), &finished);
+      if (stepped && finished) {
+        break;
       }
-    } else {
-      printf("  <anonymous:%" PRIx64 ">", map_info->offset);
     }
-    uint64_t func_offset;
-    if (elf->GetFunctionName(adjusted_rel_pc, &name, &func_offset)) {
-      printf(" (%s", name.c_str());
-      if (func_offset != 0) {
-        printf("+%" PRId64, func_offset);
+    if (!stepped) {
+      if (return_address_attempt) {
+        // We tried the return address and it didn't work, remove the last
+        // two frames. If this bad frame is the only frame, only remove
+        // the last frame.
+        frames.pop_back();
+        if (frame_num != 1) {
+          frames.pop_back();
+        }
+        break;
+      } else {
+        // Steping didn't work, try this secondary method.
+        if (!regs->SetPcFromReturnAddress(process_memory.get())) {
+          break;
+        }
+        return_address_attempt = true;
       }
-      printf(")");
+    } else {
+      return_address_attempt = false;
     }
-    printf("\n");
+  }
 
-    if (!elf->Step(rel_pc + map_info->elf_offset, regs, process_memory.get())) {
-      break;
-    }
+  // Print the frames.
+  for (auto& frame : frames) {
+    printf("%s\n", frame.c_str());
   }
 }