Find first non-zero jit debug entry.

Sometimes a process will have multiple shared libraries loaded
that have defined __jit_debug_descriptor. Specifically, art testing
will load libart.so and libartd.so, which would have broken unwinding
through jit'd code for art testing if libart.so winds up being found first.
In order to avoid duplicating the code for the linker to figure out
which one is live, change the algorithm to find the first non-zero
first_entry_ set in __jit_debug_descriptor.

Bug: 68396769

Test: Passes unit tests.
Test: Verified this can unwind 137-cfi on arm/arm64.
Change-Id: Ic4d403065d2c6f22476ef0171e7add17cd1464cd
diff --git a/libunwindstack/tests/UnwindOfflineTest.cpp b/libunwindstack/tests/UnwindOfflineTest.cpp
index 9216204..582ac18 100644
--- a/libunwindstack/tests/UnwindOfflineTest.cpp
+++ b/libunwindstack/tests/UnwindOfflineTest.cpp
@@ -406,4 +406,223 @@
       frame_info);
 }
 
+TEST(UnwindOfflineTest, jit_debug_arm32) {
+  std::string dir(TestGetFileDirectory() + "offline/jit_debug_arm32/");
+
+  MemoryOfflineParts* memory = new MemoryOfflineParts;
+  AddMemory(dir + "descriptor.data", memory);
+  AddMemory(dir + "descriptor1.data", memory);
+  AddMemory(dir + "stack.data", memory);
+  for (size_t i = 0; i < 7; i++) {
+    AddMemory(dir + "entry" + std::to_string(i) + ".data", memory);
+    AddMemory(dir + "jit" + std::to_string(i) + ".data", memory);
+  }
+
+  FILE* fp = fopen((dir + "regs.txt").c_str(), "r");
+  ASSERT_TRUE(fp != nullptr);
+  RegsArm regs;
+  uint64_t reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r0: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R0] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r1: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R1] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r2: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R2] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r3: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R3] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r4: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R4] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r5: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R5] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r6: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R6] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r7: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R7] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r8: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R8] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r9: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R9] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r10: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R10] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "r11: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R11] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "ip: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_R12] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "sp: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_SP] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "lr: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_LR] = reg_value;
+  ASSERT_EQ(1, fscanf(fp, "pc: %" SCNx64 "\n", &reg_value));
+  regs[ARM_REG_PC] = reg_value;
+  regs.SetFromRaw();
+  fclose(fp);
+
+  fp = fopen((dir + "maps.txt").c_str(), "r");
+  ASSERT_TRUE(fp != nullptr);
+  // The file is guaranteed to be less than 4096 bytes.
+  std::vector<char> buffer(4096);
+  ASSERT_NE(0U, fread(buffer.data(), 1, buffer.size(), fp));
+  fclose(fp);
+
+  BufferMaps maps(buffer.data());
+  ASSERT_TRUE(maps.Parse());
+
+  ASSERT_EQ(ARCH_ARM, regs.Arch());
+
+  std::shared_ptr<Memory> process_memory(memory);
+
+  char* cwd = getcwd(nullptr, 0);
+  ASSERT_EQ(0, chdir(dir.c_str()));
+  JitDebug jit_debug(process_memory);
+  Unwinder unwinder(128, &maps, &regs, process_memory);
+  unwinder.SetJitDebug(&jit_debug, regs.Arch());
+  unwinder.Unwind();
+  ASSERT_EQ(0, chdir(cwd));
+  free(cwd);
+
+  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"
+      "  #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"
+      "  #03 pc 00462175  libartd.so (art_quick_invoke_stub_internal+68)\n"
+      "  #04 pc 00467129  libartd.so (art_quick_invoke_stub+228)\n"
+      "  #05 pc 000bf7a9  libartd.so "
+      "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+864)\n"
+      "  #06 pc 00247833  libartd.so "
+      "(_ZN3art11interpreter34ArtInterpreterToCompiledCodeBridgeEPNS_6ThreadEPNS_9ArtMethodEPNS_"
+      "11ShadowFrameEtPNS_6JValueE+382)\n"
+      "  #07 pc 0022e935  libartd.so "
+      "(_ZN3art11interpreterL7ExecuteEPNS_6ThreadERKNS_20CodeItemDataAccessorERNS_11ShadowFrameENS_"
+      "6JValueEb+244)\n"
+      "  #08 pc 0022f71d  libartd.so "
+      "(_ZN3art11interpreter30EnterInterpreterFromEntryPointEPNS_6ThreadERKNS_"
+      "20CodeItemDataAccessorEPNS_11ShadowFrameE+128)\n"
+      "  #09 pc 00442865  libartd.so (artQuickToInterpreterBridge+796)\n"
+      "  #10 pc 004666ff  libartd.so (art_quick_to_interpreter_bridge+30)\n"
+      "  #11 pc 00011c31  anonymous:e2796000 (int Main.compare(Main, Main)+64)\n"
+      "  #12 pc 00462175  libartd.so (art_quick_invoke_stub_internal+68)\n"
+      "  #13 pc 00467129  libartd.so (art_quick_invoke_stub+228)\n"
+      "  #14 pc 000bf7a9  libartd.so "
+      "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+864)\n"
+      "  #15 pc 00247833  libartd.so "
+      "(_ZN3art11interpreter34ArtInterpreterToCompiledCodeBridgeEPNS_6ThreadEPNS_9ArtMethodEPNS_"
+      "11ShadowFrameEtPNS_6JValueE+382)\n"
+      "  #16 pc 0022e935  libartd.so "
+      "(_ZN3art11interpreterL7ExecuteEPNS_6ThreadERKNS_20CodeItemDataAccessorERNS_11ShadowFrameENS_"
+      "6JValueEb+244)\n"
+      "  #17 pc 0022f71d  libartd.so "
+      "(_ZN3art11interpreter30EnterInterpreterFromEntryPointEPNS_6ThreadERKNS_"
+      "20CodeItemDataAccessorEPNS_11ShadowFrameE+128)\n"
+      "  #18 pc 00442865  libartd.so (artQuickToInterpreterBridge+796)\n"
+      "  #19 pc 004666ff  libartd.so (art_quick_to_interpreter_bridge+30)\n"
+      "  #20 pc 00011b77  anonymous:e2796000 (int Main.compare(java.lang.Object, "
+      "java.lang.Object)+118)\n"
+      "  #21 pc 00462175  libartd.so (art_quick_invoke_stub_internal+68)\n"
+      "  #22 pc 00467129  libartd.so (art_quick_invoke_stub+228)\n"
+      "  #23 pc 000bf7a9  libartd.so "
+      "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+864)\n"
+      "  #24 pc 00247833  libartd.so "
+      "(_ZN3art11interpreter34ArtInterpreterToCompiledCodeBridgeEPNS_6ThreadEPNS_9ArtMethodEPNS_"
+      "11ShadowFrameEtPNS_6JValueE+382)\n"
+      "  #25 pc 0022e935  libartd.so "
+      "(_ZN3art11interpreterL7ExecuteEPNS_6ThreadERKNS_20CodeItemDataAccessorERNS_11ShadowFrameENS_"
+      "6JValueEb+244)\n"
+      "  #26 pc 0022f71d  libartd.so "
+      "(_ZN3art11interpreter30EnterInterpreterFromEntryPointEPNS_6ThreadERKNS_"
+      "20CodeItemDataAccessorEPNS_11ShadowFrameE+128)\n"
+      "  #27 pc 00442865  libartd.so (artQuickToInterpreterBridge+796)\n"
+      "  #28 pc 004666ff  libartd.so (art_quick_to_interpreter_bridge+30)\n"
+      "  #29 pc 00011a29  anonymous:e2796000 (int "
+      "java.util.Arrays.binarySearch0(java.lang.Object[], int, int, java.lang.Object, "
+      "java.util.Comparator)+304)\n"
+      "  #30 pc 00462175  libartd.so (art_quick_invoke_stub_internal+68)\n"
+      "  #31 pc 0046722f  libartd.so (art_quick_invoke_static_stub+226)\n"
+      "  #32 pc 000bf7bb  libartd.so "
+      "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+882)\n"
+      "  #33 pc 00247833  libartd.so "
+      "(_ZN3art11interpreter34ArtInterpreterToCompiledCodeBridgeEPNS_6ThreadEPNS_9ArtMethodEPNS_"
+      "11ShadowFrameEtPNS_6JValueE+382)\n"
+      "  #34 pc 0022e935  libartd.so "
+      "(_ZN3art11interpreterL7ExecuteEPNS_6ThreadERKNS_20CodeItemDataAccessorERNS_11ShadowFrameENS_"
+      "6JValueEb+244)\n"
+      "  #35 pc 0022f71d  libartd.so "
+      "(_ZN3art11interpreter30EnterInterpreterFromEntryPointEPNS_6ThreadERKNS_"
+      "20CodeItemDataAccessorEPNS_11ShadowFrameE+128)\n"
+      "  #36 pc 00442865  libartd.so (artQuickToInterpreterBridge+796)\n"
+      "  #37 pc 004666ff  libartd.so (art_quick_to_interpreter_bridge+30)\n"
+      "  #38 pc 0001139b  anonymous:e2796000 (boolean Main.foo()+178)\n"
+      "  #39 pc 00462175  libartd.so (art_quick_invoke_stub_internal+68)\n"
+      "  #40 pc 00467129  libartd.so (art_quick_invoke_stub+228)\n"
+      "  #41 pc 000bf7a9  libartd.so "
+      "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+864)\n"
+      "  #42 pc 00247833  libartd.so "
+      "(_ZN3art11interpreter34ArtInterpreterToCompiledCodeBridgeEPNS_6ThreadEPNS_9ArtMethodEPNS_"
+      "11ShadowFrameEtPNS_6JValueE+382)\n"
+      "  #43 pc 0022e935  libartd.so "
+      "(_ZN3art11interpreterL7ExecuteEPNS_6ThreadERKNS_20CodeItemDataAccessorERNS_11ShadowFrameENS_"
+      "6JValueEb+244)\n"
+      "  #44 pc 0022f71d  libartd.so "
+      "(_ZN3art11interpreter30EnterInterpreterFromEntryPointEPNS_6ThreadERKNS_"
+      "20CodeItemDataAccessorEPNS_11ShadowFrameE+128)\n"
+      "  #45 pc 00442865  libartd.so (artQuickToInterpreterBridge+796)\n"
+      "  #46 pc 004666ff  libartd.so (art_quick_to_interpreter_bridge+30)\n"
+      "  #47 pc 00010aa7  anonymous:e2796000 (void Main.runPrimary()+70)\n"
+      "  #48 pc 00462175  libartd.so (art_quick_invoke_stub_internal+68)\n"
+      "  #49 pc 00467129  libartd.so (art_quick_invoke_stub+228)\n"
+      "  #50 pc 000bf7a9  libartd.so "
+      "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+864)\n"
+      "  #51 pc 00247833  libartd.so "
+      "(_ZN3art11interpreter34ArtInterpreterToCompiledCodeBridgeEPNS_6ThreadEPNS_9ArtMethodEPNS_"
+      "11ShadowFrameEtPNS_6JValueE+382)\n"
+      "  #52 pc 0022e935  libartd.so "
+      "(_ZN3art11interpreterL7ExecuteEPNS_6ThreadERKNS_20CodeItemDataAccessorERNS_11ShadowFrameENS_"
+      "6JValueEb+244)\n"
+      "  #53 pc 0022f71d  libartd.so "
+      "(_ZN3art11interpreter30EnterInterpreterFromEntryPointEPNS_6ThreadERKNS_"
+      "20CodeItemDataAccessorEPNS_11ShadowFrameE+128)\n"
+      "  #54 pc 00442865  libartd.so (artQuickToInterpreterBridge+796)\n"
+      "  #55 pc 004666ff  libartd.so (art_quick_to_interpreter_bridge+30)\n"
+      "  #56 pc 0000ba99  anonymous:e2796000 (void Main.main(java.lang.String[])+144)\n"
+      "  #57 pc 00462175  libartd.so (art_quick_invoke_stub_internal+68)\n"
+      "  #58 pc 0046722f  libartd.so (art_quick_invoke_static_stub+226)\n"
+      "  #59 pc 000bf7bb  libartd.so "
+      "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+882)\n"
+      "  #60 pc 00247833  libartd.so "
+      "(_ZN3art11interpreter34ArtInterpreterToCompiledCodeBridgeEPNS_6ThreadEPNS_9ArtMethodEPNS_"
+      "11ShadowFrameEtPNS_6JValueE+382)\n"
+      "  #61 pc 0022e935  libartd.so "
+      "(_ZN3art11interpreterL7ExecuteEPNS_6ThreadERKNS_20CodeItemDataAccessorERNS_11ShadowFrameENS_"
+      "6JValueEb+244)\n"
+      "  #62 pc 0022f71d  libartd.so "
+      "(_ZN3art11interpreter30EnterInterpreterFromEntryPointEPNS_6ThreadERKNS_"
+      "20CodeItemDataAccessorEPNS_11ShadowFrameE+128)\n"
+      "  #63 pc 00442865  libartd.so (artQuickToInterpreterBridge+796)\n"
+      "  #64 pc 004666ff  libartd.so (art_quick_to_interpreter_bridge+30)\n"
+      "  #65 pc 00462175  libartd.so (art_quick_invoke_stub_internal+68)\n"
+      "  #66 pc 0046722f  libartd.so (art_quick_invoke_static_stub+226)\n"
+      "  #67 pc 000bf7bb  libartd.so "
+      "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+882)\n"
+      "  #68 pc 003b292d  libartd.so "
+      "(_ZN3artL18InvokeWithArgArrayERKNS_33ScopedObjectAccessAlreadyRunnableEPNS_9ArtMethodEPNS_"
+      "8ArgArrayEPNS_6JValueEPKc+52)\n"
+      "  #69 pc 003b26c3  libartd.so "
+      "(_ZN3art17InvokeWithVarArgsERKNS_33ScopedObjectAccessAlreadyRunnableEP8_jobjectP10_"
+      "jmethodIDSt9__va_list+210)\n"
+      "  #70 pc 00308411  libartd.so "
+      "(_ZN3art3JNI21CallStaticVoidMethodVEP7_JNIEnvP7_jclassP10_jmethodIDSt9__va_list+76)\n"
+      "  #71 pc 000e6a9f  libartd.so "
+      "(_ZN3art8CheckJNI11CallMethodVEPKcP7_JNIEnvP8_jobjectP7_jclassP10_jmethodIDSt9__va_listNS_"
+      "9Primitive4TypeENS_10InvokeTypeE+1486)\n"
+      "  #72 pc 000e19b9  libartd.so "
+      "(_ZN3art8CheckJNI21CallStaticVoidMethodVEP7_JNIEnvP7_jclassP10_jmethodIDSt9__va_list+40)\n"
+      "  #73 pc 0000159f  dalvikvm32 "
+      "(_ZN7_JNIEnv20CallStaticVoidMethodEP7_jclassP10_jmethodIDz+30)\n"
+      "  #74 pc 00001349  dalvikvm32 (main+896)\n"
+      "  #75 pc 000850c9  libc.so\n",
+      frame_info);
+}
+
 }  // namespace unwindstack