Add some extra apis to remill arch for instruction minimum size and a…

…lignment (#549)
lifting-bits · Oct 10, 2021 · 7220001 · 7220001
1 parent 75a9e04
commit 7220001
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Showing 7 changed files with 92 additions and 34 deletions.
diff --git a/include/remill/Arch/Arch.h b/include/remill/Arch/Arch.h
@@ -208,8 +208,18 @@ class Arch {
     return this->DecodeInstruction(address, instr_bytes, inst);
   }
 
+  // Minimum alignment of an instruction for this particular architecture.
+  virtual uint64_t MinInstructionAlign(void) const = 0;
+
+  // Minimum number of bytes in an instruction for this particular architecture.
+  virtual uint64_t MinInstructionSize(void) const = 0;
+
   // Maximum number of bytes in an instruction for this particular architecture.
-  virtual uint64_t MaxInstructionSize(void) const = 0;
+  //
+  // `permit_fuse_idioms` is `true` if Remill is allowed to decode multiple
+  // instructions at a time and look for instruction fusing idioms that are
+  // common to this architecture.
+  virtual uint64_t MaxInstructionSize(bool permit_fuse_idioms=true) const = 0;
 
   // Default calling convention for this architecture.
   virtual llvm::CallingConv::ID DefaultCallingConv(void) const = 0;

diff --git a/lib/Arch/AArch32/Arch.cpp b/lib/Arch/AArch32/Arch.cpp
@@ -51,8 +51,17 @@ AArch32Arch::AArch32Arch(llvm::LLVMContext *context_, OSName os_name_,
 
 AArch32Arch::~AArch32Arch(void) {}
 
+// TODO(pag): Eventually handle Thumb2 and unaligned addresses.
+uint64_t AArch32Arch::MinInstructionAlign(void) const {
+  return 4;
+}
+
+uint64_t AArch32Arch::MinInstructionSize(void) const {
+  return 4;
+}
+
 // Maximum number of bytes in an instruction for this particular architecture.
-uint64_t AArch32Arch::MaxInstructionSize(void) const {
+uint64_t AArch32Arch::MaxInstructionSize(bool) const {
   return 4;
 }
 

diff --git a/lib/Arch/AArch32/Arch.h b/lib/Arch/AArch32/Arch.h
@@ -27,27 +27,29 @@ class AArch32Arch final : public Arch {
   virtual ~AArch32Arch(void);
 
   // Returns the name of the stack pointer register.
-  std::string_view StackPointerRegisterName(void) const override;
+  std::string_view StackPointerRegisterName(void) const final;
 
   // Returns the name of the program counter register.
-  std::string_view ProgramCounterRegisterName(void) const override;
+  std::string_view ProgramCounterRegisterName(void) const final;
 
   // Decode an instuction.
   bool DecodeInstruction(uint64_t address, std::string_view inst_bytes,
-                         Instruction &inst) const override;
+                         Instruction &inst) const final;
 
-  // Maximum number of bytes in an instruction.
-  uint64_t MaxInstructionSize(void) const override;
+  // Align/Minimum/Maximum number of bytes in an instruction.
+  uint64_t MinInstructionAlign(void) const final;
+  uint64_t MinInstructionSize(void) const final;
+  uint64_t MaxInstructionSize(bool permit_fuse_idioms) const final;
 
-  llvm::Triple Triple(void) const override;
-  llvm::DataLayout DataLayout(void) const override;
+  llvm::Triple Triple(void) const final;
+  llvm::DataLayout DataLayout(void) const final;
 
   // Default calling convention for this architecture.
-  llvm::CallingConv::ID DefaultCallingConv(void) const override;
+  llvm::CallingConv::ID DefaultCallingConv(void) const final;
 
   // Populate the `__remill_basic_block` function with variables.
   void PopulateBasicBlockFunction(llvm::Module *module,
-                                  llvm::Function *bb_func) const override;
+                                  llvm::Function *bb_func) const final;
 
  private:
   AArch32Arch(void) = delete;

diff --git a/lib/Arch/AArch64/Arch.cpp b/lib/Arch/AArch64/Arch.cpp
@@ -113,27 +113,29 @@ class AArch64Arch final : public Arch {
   virtual ~AArch64Arch(void);
 
   // Returns the name of the stack pointer register.
-  std::string_view StackPointerRegisterName(void) const override;
+  std::string_view StackPointerRegisterName(void) const final;
 
   // Returns the name of the program counter register.
-  std::string_view ProgramCounterRegisterName(void) const override;
+  std::string_view ProgramCounterRegisterName(void) const final;
 
   // Decode an instruction.
   bool DecodeInstruction(uint64_t address, std::string_view instr_bytes,
-                         Instruction &inst) const override;
+                         Instruction &inst) const final;
 
-  // Maximum number of bytes in an instruction.
-  uint64_t MaxInstructionSize(void) const override;
+  // Align/Minimum/Maximum number of bytes in an instruction.
+  uint64_t MinInstructionAlign(void) const final;
+  uint64_t MinInstructionSize(void) const final;
+  uint64_t MaxInstructionSize(bool permit_fuse_idioms) const final;
 
-  llvm::Triple Triple(void) const override;
-  llvm::DataLayout DataLayout(void) const override;
+  llvm::Triple Triple(void) const final;
+  llvm::DataLayout DataLayout(void) const final;
 
   // Default calling convention for this architecture.
-  llvm::CallingConv::ID DefaultCallingConv(void) const override;
+  llvm::CallingConv::ID DefaultCallingConv(void) const final;
 
   // Populate the `__remill_basic_block` function with variables.
   void PopulateBasicBlockFunction(llvm::Module *module,
-                                  llvm::Function *bb_func) const override;
+                                  llvm::Function *bb_func) const final;
 
  private:
   AArch64Arch(void) = delete;
@@ -473,8 +475,17 @@ void AArch64Arch::PopulateBasicBlockFunction(llvm::Module *module,
   (void) this->RegisterByName(kPCVariableName)->AddressOf(state_ptr_arg, ir);
 }
 
+// TODO(pag): Eventually handle Thumb2 and unaligned addresses.
+uint64_t AArch64Arch::MinInstructionAlign(void) const {
+  return 4;
+}
+
+uint64_t AArch64Arch::MinInstructionSize(void) const {
+  return 4;
+}
+
 // Maximum number of bytes in an instruction for this particular architecture.
-uint64_t AArch64Arch::MaxInstructionSize(void) const {
+uint64_t AArch64Arch::MaxInstructionSize(bool) const {
   return 4;
 }
 

diff --git a/lib/Arch/SPARC32/Arch.cpp b/lib/Arch/SPARC32/Arch.cpp
@@ -148,9 +148,17 @@ class SPARC32Arch final : public Arch {
     return kPCRegName;
   }
 
+  uint64_t MinInstructionAlign(void) const final {
+    return 4;
+  }
+
+  uint64_t MinInstructionSize(void) const final {
+    return 4;
+  }
+
   // Maximum number of bytes in an instruction.
-  uint64_t MaxInstructionSize(void) const final {
-    return 8;  // To handle `SET` idioms.
+  uint64_t MaxInstructionSize(bool permit_fuse_idioms) const final {
+    return permit_fuse_idioms ? 8 : 4;  // To handle `SET` idioms.
   }
 
   // Default calling convention for this architecture.

diff --git a/lib/Arch/SPARC64/Arch.cpp b/lib/Arch/SPARC64/Arch.cpp
@@ -56,9 +56,17 @@ class SPARC64Arch final : public Arch {
     return kPCRegName;
   }
 
+  uint64_t MinInstructionAlign(void) const final {
+    return 4;
+  }
+
+  uint64_t MinInstructionSize(void) const final {
+    return 4;
+  }
+
   // Maximum number of bytes in an instruction.
-  uint64_t MaxInstructionSize(void) const final {
-    return 8;  // To handle `SET` idioms.
+  uint64_t MaxInstructionSize(bool permit_fuse_idioms) const final {
+    return permit_fuse_idioms ? 8 : 4;  // To handle `SET` idioms.
   }
 
   // Default calling convention for this architecture.

diff --git a/lib/Arch/X86/Arch.cpp b/lib/Arch/X86/Arch.cpp
@@ -793,27 +793,29 @@ class X86Arch final : public Arch {
   virtual ~X86Arch(void);
 
   // Returns the name of the stack pointer register.
-  std::string_view StackPointerRegisterName(void) const override;
+  std::string_view StackPointerRegisterName(void) const final;
 
   // Returns the name of the program counter register.
-  std::string_view ProgramCounterRegisterName(void) const override;
+  std::string_view ProgramCounterRegisterName(void) const final;
 
   // Decode an instruction.
   bool DecodeInstruction(uint64_t address, std::string_view inst_bytes,
-                         Instruction &inst) const override;
+                         Instruction &inst) const final;
 
   // Maximum number of bytes in an instruction.
-  uint64_t MaxInstructionSize(void) const override;
+  uint64_t MinInstructionAlign(void) const final;
+  uint64_t MinInstructionSize(void) const final;
+  uint64_t MaxInstructionSize(bool permit_fuse_idioms) const final;
 
-  llvm::Triple Triple(void) const override;
-  llvm::DataLayout DataLayout(void) const override;
+  llvm::Triple Triple(void) const final;
+  llvm::DataLayout DataLayout(void) const final;
 
   // Default calling convention for this architecture.
-  llvm::CallingConv::ID DefaultCallingConv(void) const override;
+  llvm::CallingConv::ID DefaultCallingConv(void) const final;
 
   // Populate the `__remill_basic_block` function with variables.
   void PopulateBasicBlockFunction(llvm::Module *module,
-                                  llvm::Function *bb_func) const override;
+                                  llvm::Function *bb_func) const final;
 
  private:
   X86Arch(void) = delete;
@@ -833,8 +835,16 @@ X86Arch::X86Arch(llvm::LLVMContext *context_, OSName os_name_,
 
 X86Arch::~X86Arch(void) {}
 
+uint64_t X86Arch::MinInstructionAlign(void) const {
+  return 1;
+}
+
+uint64_t X86Arch::MinInstructionSize(void) const {
+  return 1;
+}
+
 // Maximum number of bytes in an instruction for this particular architecture.
-uint64_t X86Arch::MaxInstructionSize(void) const {
+uint64_t X86Arch::MaxInstructionSize(bool) const {
   return 15;
 }