Fix handling of load bias values.

It turns out that for the dwarf information, if a FDE indicates it's pc
relative, then pc has to be incremented by the load bias. If not, then
it should not be incremented.

Previously, the code always subtracted load bias values from pcs, and assumed
that all fdes were incremented by load bias values. The new code actually
reads the fdes and adjusted the pcs in the fde and in the eh frame hdr so
that load bias values are already handled properly.

In addition, add dumping of arm exidx values in unwind_reg_info. This allowed
verifying that the debug frame in those elf files was being handled properly.

Added a new unit test that only has a debug frame that has a non-zero load
bias and has fde entries that do not have pc relative encoding.

Fix a couple of other small bugs.

Bug: 109824792

Test: All libbacktrace/libunwindstack unit tests pass.
Test: Ran ART 137-cfi test and 004-ThreadStress.
Test: Verify that displaying the fde start and end pc actually match the
Test: real data for fde that have pc relative set, and that don't.
Test: Verified that the unwind information for arm exidx matches the
Test: debug frame data.

Change-Id: I707555286b5cb05df9f25489e8c5ede753cfe0fb

2 files changed, 22 insertions, 20 deletions

diff --git a/libunwindstack/include/unwindstack/DwarfSection.h b/libunwindstack/include/unwindstack/DwarfSection.h
index 209c54a..847f382 100644
--- a/libunwindstack/include/unwindstack/DwarfSection.h
+++ b/libunwindstack/include/unwindstack/DwarfSection.h
@@ -78,13 +78,13 @@ class DwarfSection {
   DwarfErrorCode LastErrorCode() { return last_error_.code; }
   uint64_t LastErrorAddress() { return last_error_.address; }
 
-  virtual bool Init(uint64_t offset, uint64_t size) = 0;
+  virtual bool Init(uint64_t offset, uint64_t size, uint64_t load_bias) = 0;
 
   virtual bool Eval(const DwarfCie*, Memory*, const dwarf_loc_regs_t&, Regs*, bool*) = 0;
 
   virtual bool GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) = 0;
 
-  virtual bool Log(uint8_t indent, uint64_t pc, uint64_t load_bias, const DwarfFde* fde) = 0;
+  virtual bool Log(uint8_t indent, uint64_t pc, const DwarfFde* fde) = 0;
 
   virtual const DwarfFde* GetFdeFromIndex(size_t index) = 0;
 
@@ -131,7 +131,7 @@ class DwarfSectionImpl : public DwarfSection {
   DwarfSectionImpl(Memory* memory) : DwarfSection(memory) {}
   virtual ~DwarfSectionImpl() = default;
 
-  bool Init(uint64_t offset, uint64_t size) override;
+  bool Init(uint64_t offset, uint64_t size, uint64_t load_bias) override;
 
   bool GetFdeOffsetFromPc(uint64_t pc, uint64_t* fde_offset) override;
 
@@ -150,7 +150,7 @@ class DwarfSectionImpl : public DwarfSection {
 
   bool GetCfaLocationInfo(uint64_t pc, const DwarfFde* fde, dwarf_loc_regs_t* loc_regs) override;
 
-  bool Log(uint8_t indent, uint64_t pc, uint64_t load_bias, const DwarfFde* fde) override;
+  bool Log(uint8_t indent, uint64_t pc, const DwarfFde* fde) override;
 
  protected:
   bool EvalExpression(const DwarfLocation& loc, Memory* regular_memory, AddressType* value,
@@ -162,6 +162,9 @@ class DwarfSectionImpl : public DwarfSection {
 
   bool CreateSortedFdeList();
 
+  uint64_t load_bias_ = 0;
+  uint64_t pc_offset_ = 0;
+
   std::vector<FdeInfo> fdes_;
   uint64_t entries_offset_;
   uint64_t entries_end_;
diff --git a/libunwindstack/include/unwindstack/ElfInterface.h b/libunwindstack/include/unwindstack/ElfInterface.h
index 3a221bc..4d25c40 100644
--- a/libunwindstack/include/unwindstack/ElfInterface.h
+++ b/libunwindstack/include/unwindstack/ElfInterface.h
@@ -54,17 +54,15 @@ class ElfInterface {
 
   virtual bool Init(uint64_t* load_bias) = 0;
 
-  virtual void InitHeaders() = 0;
+  virtual void InitHeaders(uint64_t load_bias) = 0;
 
   virtual bool GetSoname(std::string* name) = 0;
 
-  virtual bool GetFunctionName(uint64_t addr, uint64_t load_bias, std::string* name,
-                               uint64_t* offset) = 0;
+  virtual bool GetFunctionName(uint64_t addr, std::string* name, uint64_t* offset) = 0;
 
   virtual bool GetGlobalVariable(const std::string& name, uint64_t* memory_address) = 0;
 
-  virtual bool Step(uint64_t rel_pc, uint64_t load_bias, Regs* regs, Memory* process_memory,
-                    bool* finished);
+  virtual bool Step(uint64_t rel_pc, Regs* regs, Memory* process_memory, bool* finished);
 
   virtual bool IsValidPc(uint64_t pc);
 
@@ -100,7 +98,7 @@ class ElfInterface {
 
  protected:
   template <typename AddressType>
-  void InitHeadersWithTemplate();
+  void InitHeadersWithTemplate(uint64_t load_bias);
 
   template <typename EhdrType, typename PhdrType, typename ShdrType>
   bool ReadAllHeaders(uint64_t* load_bias);
@@ -115,8 +113,7 @@ class ElfInterface {
   bool GetSonameWithTemplate(std::string* soname);
 
   template <typename SymType>
-  bool GetFunctionNameWithTemplate(uint64_t addr, uint64_t load_bias, std::string* name,
-                                   uint64_t* func_offset);
+  bool GetFunctionNameWithTemplate(uint64_t addr, std::string* name, uint64_t* func_offset);
 
   template <typename SymType>
   bool GetGlobalVariableWithTemplate(const std::string& name, uint64_t* memory_address);
@@ -169,15 +166,16 @@ class ElfInterface32 : public ElfInterface {
     return ElfInterface::ReadAllHeaders<Elf32_Ehdr, Elf32_Phdr, Elf32_Shdr>(load_bias);
   }
 
-  void InitHeaders() override { ElfInterface::InitHeadersWithTemplate<uint32_t>(); }
+  void InitHeaders(uint64_t load_bias) override {
+    ElfInterface::InitHeadersWithTemplate<uint32_t>(load_bias);
+  }
 
   bool GetSoname(std::string* soname) override {
     return ElfInterface::GetSonameWithTemplate<Elf32_Dyn>(soname);
   }
 
-  bool GetFunctionName(uint64_t addr, uint64_t load_bias, std::string* name,
-                       uint64_t* func_offset) override {
-    return ElfInterface::GetFunctionNameWithTemplate<Elf32_Sym>(addr, load_bias, name, func_offset);
+  bool GetFunctionName(uint64_t addr, std::string* name, uint64_t* func_offset) override {
+    return ElfInterface::GetFunctionNameWithTemplate<Elf32_Sym>(addr, name, func_offset);
   }
 
   bool GetGlobalVariable(const std::string& name, uint64_t* memory_address) override {
@@ -198,15 +196,16 @@ class ElfInterface64 : public ElfInterface {
     return ElfInterface::ReadAllHeaders<Elf64_Ehdr, Elf64_Phdr, Elf64_Shdr>(load_bias);
   }
 
-  void InitHeaders() override { ElfInterface::InitHeadersWithTemplate<uint64_t>(); }
+  void InitHeaders(uint64_t load_bias) override {
+    ElfInterface::InitHeadersWithTemplate<uint64_t>(load_bias);
+  }
 
   bool GetSoname(std::string* soname) override {
     return ElfInterface::GetSonameWithTemplate<Elf64_Dyn>(soname);
   }
 
-  bool GetFunctionName(uint64_t addr, uint64_t load_bias, std::string* name,
-                       uint64_t* func_offset) override {
-    return ElfInterface::GetFunctionNameWithTemplate<Elf64_Sym>(addr, load_bias, name, func_offset);
+  bool GetFunctionName(uint64_t addr, std::string* name, uint64_t* func_offset) override {
+    return ElfInterface::GetFunctionNameWithTemplate<Elf64_Sym>(addr, name, func_offset);
   }
 
   bool GetGlobalVariable(const std::string& name, uint64_t* memory_address) override {