Fix another set of bugs.

- The pc read from the eh frame binary table of pc/fde offset is off by 4.
  I verified that on arm/arm64/x86/x86_64 the pc in this table matches
  the fde pc_start value. I did this by adding an error if this occurred
  and ran unwind_info over everything in system/lib, system/lib64, system/bin.
- Fixed unit tests for the above change.
- Fix a small bug in the processing encoded values. The high
  bit of the encoding should be masked off, but I wasn't doing that. That
  meant during processing of the fde, I was incorrectly returning
  an error because the encoded value was unknown.
- Added a new test for this encoding change.

Bug: 23762183

Test: Build and all unit tests pass. Also, see above comments.
Change-Id: If074a410a1726392274cd72c64470ca0be48e0db

libunwindstack/DwarfEhFrame.cpp

@@ -100,7 +100,7 @@ const typename DwarfEhFrame<AddressType>::FdeInfo* DwarfEhFrame<AddressType>::Ge
     fde_info_.erase(index);
     return nullptr;
   }
-  info->pc = value;
+  info->pc = value + 4;
   return info;
 }
 
@@ -175,7 +175,7 @@ bool DwarfEhFrame<AddressType>::GetFdeOffsetSequential(uint64_t pc, uint64_t* fd
       last_error_ = DWARF_ERROR_MEMORY_INVALID;
       return false;
     }
-    info->pc = value;
+    info->pc = value + 4;
 
     if (pc < info->pc) {
       if (prev_info == nullptr) {

libunwindstack/DwarfMemory.cpp

@@ -235,7 +235,7 @@ bool DwarfMemory::ReadEncodedValue(uint8_t encoding, uint64_t* value) {
       return false;
   }
 
-  return AdjustEncodedValue(encoding & 0xf0, value);
+  return AdjustEncodedValue(encoding & 0x70, value);
 }
 
 // Instantiate all of the needed template functions.

libunwindstack/tests/DwarfEhFrameTest.cpp

@@ -124,7 +124,7 @@ TYPED_TEST_P(DwarfEhFrameTest, GetFdeInfoFromIndex_read_pcrel) {
 
   auto info = this->eh_frame_->GetFdeInfoFromIndex(2);
   ASSERT_TRUE(info != nullptr);
-  EXPECT_EQ(0x1380U, info->pc);
+  EXPECT_EQ(0x1384U, info->pc);
   EXPECT_EQ(0x1540U, info->offset);
 }
 
@@ -139,7 +139,7 @@ TYPED_TEST_P(DwarfEhFrameTest, GetFdeInfoFromIndex_read_datarel) {
 
   auto info = this->eh_frame_->GetFdeInfoFromIndex(2);
   ASSERT_TRUE(info != nullptr);
-  EXPECT_EQ(0x3340U, info->pc);
+  EXPECT_EQ(0x3344U, info->pc);
   EXPECT_EQ(0x3500U, info->offset);
 }
 
@@ -153,7 +153,7 @@ TYPED_TEST_P(DwarfEhFrameTest, GetFdeInfoFromIndex_cached) {
 
   auto info = this->eh_frame_->GetFdeInfoFromIndex(2);
   ASSERT_TRUE(info != nullptr);
-  EXPECT_EQ(0x340U, info->pc);
+  EXPECT_EQ(0x344U, info->pc);
   EXPECT_EQ(0x500U, info->offset);
 
   // Clear the memory so that this will fail if it doesn't read cached data.
@@ -161,7 +161,7 @@ TYPED_TEST_P(DwarfEhFrameTest, GetFdeInfoFromIndex_cached) {
 
   info = this->eh_frame_->GetFdeInfoFromIndex(2);
   ASSERT_TRUE(info != nullptr);
-  EXPECT_EQ(0x340U, info->pc);
+  EXPECT_EQ(0x344U, info->pc);
   EXPECT_EQ(0x500U, info->offset);
 }
 
@@ -220,18 +220,18 @@ TYPED_TEST_P(DwarfEhFrameTest, GetFdeOffsetSequential) {
 
   // Verify that if entries is zero, that it fails.
   uint64_t fde_offset;
-  ASSERT_FALSE(this->eh_frame_->GetFdeOffsetSequential(0x340, &fde_offset));
+  ASSERT_FALSE(this->eh_frame_->GetFdeOffsetSequential(0x344, &fde_offset));
   this->eh_frame_->TestSetCurEntriesOffset(0x1040);
 
-  ASSERT_TRUE(this->eh_frame_->GetFdeOffsetSequential(0x340, &fde_offset));
+  ASSERT_TRUE(this->eh_frame_->GetFdeOffsetSequential(0x344, &fde_offset));
   EXPECT_EQ(0x500U, fde_offset);
 
-  ASSERT_TRUE(this->eh_frame_->GetFdeOffsetSequential(0x440, &fde_offset));
+  ASSERT_TRUE(this->eh_frame_->GetFdeOffsetSequential(0x444, &fde_offset));
   EXPECT_EQ(0x600U, fde_offset);
 
   // Expect that the data is cached so no more memory reads will occur.
   this->memory_.Clear();
-  ASSERT_TRUE(this->eh_frame_->GetFdeOffsetSequential(0x440, &fde_offset));
+  ASSERT_TRUE(this->eh_frame_->GetFdeOffsetSequential(0x444, &fde_offset));
   EXPECT_EQ(0x600U, fde_offset);
 }
 

libunwindstack/tests/DwarfMemoryTest.cpp

@@ -52,6 +52,8 @@ class DwarfMemoryTest : public ::testing::Test {
   void ReadEncodedValue_non_zero_adjust();
   template <typename AddressType>
   void ReadEncodedValue_overflow();
+  template <typename AddressType>
+  void ReadEncodedValue_high_bit_set();
 
   MemoryFake memory_;
   std::unique_ptr<DwarfMemory> dwarf_mem_;
@@ -435,6 +437,26 @@ TEST_F(DwarfMemoryTest, ReadEncodedValue_overflow_uint64_t) {
   ReadEncodedValue_overflow<uint64_t>();
 }
 
+template <typename AddressType>
+void DwarfMemoryTest::ReadEncodedValue_high_bit_set() {
+  uint64_t value;
+  memory_.SetData32(0, 0x15234);
+  ASSERT_FALSE(dwarf_mem_->ReadEncodedValue<AddressType>(0xc3, &value));
+
+  dwarf_mem_->set_func_offset(0x60000);
+  dwarf_mem_->set_cur_offset(0);
+  ASSERT_TRUE(dwarf_mem_->ReadEncodedValue<AddressType>(0xc3, &value));
+  ASSERT_EQ(0x75234U, value);
+}
+
+TEST_F(DwarfMemoryTest, ReadEncodedValue_high_bit_set_uint32_t) {
+  ReadEncodedValue_high_bit_set<uint32_t>();
+}
+
+TEST_F(DwarfMemoryTest, ReadEncodedValue_high_bit_set_uint64_t) {
+  ReadEncodedValue_high_bit_set<uint64_t>();
+}
+
 TEST_F(DwarfMemoryTest, AdjustEncodedValue_absptr) {
   uint64_t value = 0x1234;
   ASSERT_TRUE(dwarf_mem_->AdjustEncodedValue(0x00, &value));