Fix null pointer dereference in RegsArm.

Fix RegsArm::GetPcAdjustment to check for an invalid elf before trying
to read memory.
Modify the tests for this so it crashes without this change.

Also modify the GetPcAdjustment for all different architectures so
that unless the relative pc is too small, it will return the minimum
amount that should be adjusted. This is to handle cases where we still
want to adjust the pc but it's in an invalid elf. Mostly this is for
handling cases when the pc is in jit gdb debug code so that we use the
right unwind information.

Bug: 77233204

Test: Passes unit tests for libbacktrace/libunwindstack.
Change-Id: Id73609adaf3b80a583584441de228156fec3afa7
diff --git a/libunwindstack/tests/UnwindOfflineTest.cpp b/libunwindstack/tests/UnwindOfflineTest.cpp
index 6c242a5..2b8f0c2 100644
--- a/libunwindstack/tests/UnwindOfflineTest.cpp
+++ b/libunwindstack/tests/UnwindOfflineTest.cpp
@@ -285,7 +285,7 @@
       "  #01 pc 00067f00  libarttestd.so (Java_Main_unwindInProcess+10032)\n"
       "  #02 pc 000021a8 (offset 0x2000)  137-cfi.odex (boolean Main.unwindInProcess(boolean, int, "
       "boolean)+136)\n"
-      "  #03 pc 0000fe81  anonymous:ee74c000 (boolean Main.bar(boolean)+65)\n"
+      "  #03 pc 0000fe80  anonymous:ee74c000 (boolean Main.bar(boolean)+64)\n"
       "  #04 pc 006ad4d2  libartd.so (art_quick_invoke_stub+338)\n"
       "  #05 pc 00146ab5  libartd.so "
       "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+885)\n"
@@ -300,7 +300,7 @@
       "20CodeItemDataAccessorEPNS_11ShadowFrameE+234)\n"
       "  #09 pc 00684362  libartd.so (artQuickToInterpreterBridge+1058)\n"
       "  #10 pc 006b35bd  libartd.so (art_quick_to_interpreter_bridge+77)\n"
-      "  #11 pc 0000fe04  anonymous:ee74c000 (int Main.compare(Main, Main)+52)\n"
+      "  #11 pc 0000fe03  anonymous:ee74c000 (int Main.compare(Main, Main)+51)\n"
       "  #12 pc 006ad4d2  libartd.so (art_quick_invoke_stub+338)\n"
       "  #13 pc 00146ab5  libartd.so "
       "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+885)\n"
@@ -315,8 +315,8 @@
       "20CodeItemDataAccessorEPNS_11ShadowFrameE+234)\n"
       "  #17 pc 00684362  libartd.so (artQuickToInterpreterBridge+1058)\n"
       "  #18 pc 006b35bd  libartd.so (art_quick_to_interpreter_bridge+77)\n"
-      "  #19 pc 0000fd3c  anonymous:ee74c000 (int Main.compare(java.lang.Object, "
-      "java.lang.Object)+108)\n"
+      "  #19 pc 0000fd3b  anonymous:ee74c000 (int Main.compare(java.lang.Object, "
+      "java.lang.Object)+107)\n"
       "  #20 pc 006ad4d2  libartd.so (art_quick_invoke_stub+338)\n"
       "  #21 pc 00146ab5  libartd.so "
       "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+885)\n"
@@ -331,9 +331,9 @@
       "20CodeItemDataAccessorEPNS_11ShadowFrameE+234)\n"
       "  #25 pc 00684362  libartd.so (artQuickToInterpreterBridge+1058)\n"
       "  #26 pc 006b35bd  libartd.so (art_quick_to_interpreter_bridge+77)\n"
-      "  #27 pc 0000fbdc  anonymous:ee74c000 (int "
+      "  #27 pc 0000fbdb  anonymous:ee74c000 (int "
       "java.util.Arrays.binarySearch0(java.lang.Object[], int, int, java.lang.Object, "
-      "java.util.Comparator)+332)\n"
+      "java.util.Comparator)+331)\n"
       "  #28 pc 006ad6a2  libartd.so (art_quick_invoke_static_stub+418)\n"
       "  #29 pc 00146acb  libartd.so "
       "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+907)\n"
@@ -348,7 +348,7 @@
       "20CodeItemDataAccessorEPNS_11ShadowFrameE+234)\n"
       "  #33 pc 00684362  libartd.so (artQuickToInterpreterBridge+1058)\n"
       "  #34 pc 006b35bd  libartd.so (art_quick_to_interpreter_bridge+77)\n"
-      "  #35 pc 0000f625  anonymous:ee74c000 (boolean Main.foo()+165)\n"
+      "  #35 pc 0000f624  anonymous:ee74c000 (boolean Main.foo()+164)\n"
       "  #36 pc 006ad4d2  libartd.so (art_quick_invoke_stub+338)\n"
       "  #37 pc 00146ab5  libartd.so "
       "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+885)\n"
@@ -363,7 +363,7 @@
       "20CodeItemDataAccessorEPNS_11ShadowFrameE+234)\n"
       "  #41 pc 00684362  libartd.so (artQuickToInterpreterBridge+1058)\n"
       "  #42 pc 006b35bd  libartd.so (art_quick_to_interpreter_bridge+77)\n"
-      "  #43 pc 0000eedc  anonymous:ee74c000 (void Main.runPrimary()+60)\n"
+      "  #43 pc 0000eedb  anonymous:ee74c000 (void Main.runPrimary()+59)\n"
       "  #44 pc 006ad4d2  libartd.so (art_quick_invoke_stub+338)\n"
       "  #45 pc 00146ab5  libartd.so "
       "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+885)\n"
@@ -378,7 +378,7 @@
       "20CodeItemDataAccessorEPNS_11ShadowFrameE+234)\n"
       "  #49 pc 00684362  libartd.so (artQuickToInterpreterBridge+1058)\n"
       "  #50 pc 006b35bd  libartd.so (art_quick_to_interpreter_bridge+77)\n"
-      "  #51 pc 0000ac22  anonymous:ee74c000 (void Main.main(java.lang.String[])+98)\n"
+      "  #51 pc 0000ac21  anonymous:ee74c000 (void Main.main(java.lang.String[])+97)\n"
       "  #52 pc 006ad6a2  libartd.so (art_quick_invoke_static_stub+418)\n"
       "  #53 pc 00146acb  libartd.so "
       "(_ZN3art9ArtMethod6InvokeEPNS_6ThreadEPjjPNS_6JValueEPKc+907)\n"
@@ -420,7 +420,7 @@
   EXPECT_EQ(0xffeb52a0U, unwinder.frames()[1].sp);
   EXPECT_EQ(0xec6061a8U, unwinder.frames()[2].pc);
   EXPECT_EQ(0xffeb5ce0U, unwinder.frames()[2].sp);
-  EXPECT_EQ(0xee75be81U, unwinder.frames()[3].pc);
+  EXPECT_EQ(0xee75be80U, unwinder.frames()[3].pc);
   EXPECT_EQ(0xffeb5d30U, unwinder.frames()[3].sp);
   EXPECT_EQ(0xf728e4d2U, unwinder.frames()[4].pc);
   EXPECT_EQ(0xffeb5d60U, unwinder.frames()[4].sp);
@@ -436,7 +436,7 @@
   EXPECT_EQ(0xffeb5fb0U, unwinder.frames()[9].sp);
   EXPECT_EQ(0xf72945bdU, unwinder.frames()[10].pc);
   EXPECT_EQ(0xffeb6110U, unwinder.frames()[10].sp);
-  EXPECT_EQ(0xee75be04U, unwinder.frames()[11].pc);
+  EXPECT_EQ(0xee75be03U, unwinder.frames()[11].pc);
   EXPECT_EQ(0xffeb6160U, unwinder.frames()[11].sp);
   EXPECT_EQ(0xf728e4d2U, unwinder.frames()[12].pc);
   EXPECT_EQ(0xffeb6180U, unwinder.frames()[12].sp);
@@ -452,7 +452,7 @@
   EXPECT_EQ(0xffeb63e0U, unwinder.frames()[17].sp);
   EXPECT_EQ(0xf72945bdU, unwinder.frames()[18].pc);
   EXPECT_EQ(0xffeb6530U, unwinder.frames()[18].sp);
-  EXPECT_EQ(0xee75bd3cU, unwinder.frames()[19].pc);
+  EXPECT_EQ(0xee75bd3bU, unwinder.frames()[19].pc);
   EXPECT_EQ(0xffeb6580U, unwinder.frames()[19].sp);
   EXPECT_EQ(0xf728e4d2U, unwinder.frames()[20].pc);
   EXPECT_EQ(0xffeb65b0U, unwinder.frames()[20].sp);
@@ -468,7 +468,7 @@
   EXPECT_EQ(0xffeb6810U, unwinder.frames()[25].sp);
   EXPECT_EQ(0xf72945bdU, unwinder.frames()[26].pc);
   EXPECT_EQ(0xffeb6960U, unwinder.frames()[26].sp);
-  EXPECT_EQ(0xee75bbdcU, unwinder.frames()[27].pc);
+  EXPECT_EQ(0xee75bbdbU, unwinder.frames()[27].pc);
   EXPECT_EQ(0xffeb69b0U, unwinder.frames()[27].sp);
   EXPECT_EQ(0xf728e6a2U, unwinder.frames()[28].pc);
   EXPECT_EQ(0xffeb69f0U, unwinder.frames()[28].sp);
@@ -484,7 +484,7 @@
   EXPECT_EQ(0xffeb6c50U, unwinder.frames()[33].sp);
   EXPECT_EQ(0xf72945bdU, unwinder.frames()[34].pc);
   EXPECT_EQ(0xffeb6dd0U, unwinder.frames()[34].sp);
-  EXPECT_EQ(0xee75b625U, unwinder.frames()[35].pc);
+  EXPECT_EQ(0xee75b624U, unwinder.frames()[35].pc);
   EXPECT_EQ(0xffeb6e20U, unwinder.frames()[35].sp);
   EXPECT_EQ(0xf728e4d2U, unwinder.frames()[36].pc);
   EXPECT_EQ(0xffeb6e50U, unwinder.frames()[36].sp);
@@ -500,7 +500,7 @@
   EXPECT_EQ(0xffeb70a0U, unwinder.frames()[41].sp);
   EXPECT_EQ(0xf72945bdU, unwinder.frames()[42].pc);
   EXPECT_EQ(0xffeb71f0U, unwinder.frames()[42].sp);
-  EXPECT_EQ(0xee75aedcU, unwinder.frames()[43].pc);
+  EXPECT_EQ(0xee75aedbU, unwinder.frames()[43].pc);
   EXPECT_EQ(0xffeb7240U, unwinder.frames()[43].sp);
   EXPECT_EQ(0xf728e4d2U, unwinder.frames()[44].pc);
   EXPECT_EQ(0xffeb72a0U, unwinder.frames()[44].sp);
@@ -516,7 +516,7 @@
   EXPECT_EQ(0xffeb74f0U, unwinder.frames()[49].sp);
   EXPECT_EQ(0xf72945bdU, unwinder.frames()[50].pc);
   EXPECT_EQ(0xffeb7680U, unwinder.frames()[50].sp);
-  EXPECT_EQ(0xee756c22U, unwinder.frames()[51].pc);
+  EXPECT_EQ(0xee756c21U, unwinder.frames()[51].pc);
   EXPECT_EQ(0xffeb76d0U, unwinder.frames()[51].sp);
   EXPECT_EQ(0xf728e6a2U, unwinder.frames()[52].pc);
   EXPECT_EQ(0xffeb76f0U, unwinder.frames()[52].sp);