Error checking improvements

dyninst · Jun 20, 2016 · 476d083 · 476d083
1 parent 60f1779
commit 476d083
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Showing 2 changed files with 28 additions and 32 deletions.
diff --git a/common/src/arch-x86.C b/common/src/arch-x86.C
@@ -8210,15 +8210,6 @@ ia32_instruction& ia32_decode(unsigned int capa, const unsigned char* addr, ia32
         return instruct;
     }
 
-    /* Set the amount of prefix bytes */
-    if(instruct.loc) 
-    {
-        instruct.loc->num_prefixes = pref.getCount();
-    }
-
-    /* Adjust the instruction size for the prefixes */
-    instruct.size = pref.getCount();
-
     /* Skip the prefixes so that we don't decode them again */
     addr += instruct.size;
 

diff --git a/common/src/arch-x86.h b/common/src/arch-x86.h
@@ -409,21 +409,16 @@ enum AMD64_REG_NUMBERS {
 #define POP_EBI  (0x5e)
 #define POP_EDI  (0x5f)
 
-
 #define PUSHAD   (0x60)
 #define POPAD    (0x61)
 
-
-
-
 #define JE_R8    (0x74)
 #define JNE_R8   (0x75)
 #define JL_R8    (0x7C)
 #define JLE_R8   (0x7E)
 #define JG_R8    (0x7F)
 #define JGE_R8   (0x7D)
 
-
 #define MOVREGMEM_REG (0x8b) 
 #define MOV_R8_TO_RM8 (0x88)     //move r8 to r/m8
 #define MOV_R16_TO_RM16 (0x89)   //move r16 to r/m16
@@ -432,20 +427,12 @@ enum AMD64_REG_NUMBERS {
 #define MOV_RM16_TO_R16 (0x8b)
 #define MOV_RM32_TO_R32 (0x8b)
 
-
-
 #define NOP      (0x90)
 #define PUSHFD   (0x9C)
 #define POPFD    (0x9D)
 
-
 #define JCXZ     (0xE3)
 
-
-
-
-
-
 #define FSAVE    (0x9BDD)
 #define FSAVE_OP (6)
 
@@ -468,7 +455,6 @@ enum {
   RepGroup = 0
 };
 
-
 #ifndef VEX_PREFIX_MASKS
 #define VEX_PREFIX_MASKS
 
@@ -800,7 +786,6 @@ enum sizehacks {
   shREPNESCAS
 };
 
-
 struct ia32_condition
 {
   bool is;
@@ -811,9 +796,6 @@ struct ia32_condition
   void set(int _tttn) { is = true; tttn = _tttn; }
 };
 
-bool ia32_decode_prefixes(const unsigned char* addr, ia32_instruction& insn);
-
-
 struct ia32_operand {  // operand as given in Intel book tables
   unsigned int admet;  // addressing method
   unsigned int optype; // operand type;
@@ -861,7 +843,7 @@ class ia32_instruction
   friend bool ia32_decode_prefixes(const unsigned char* addr, ia32_instruction& insn);
   friend COMMON_EXPORT ia32_instruction& ia32_decode(unsigned int capa, const unsigned char* addr,
 		  		       ia32_instruction& instruct);
-  friend COMMON_EXPORT int ia32_decode_opcode(unsigned int capa, 
+  friend int ia32_decode_opcode(unsigned int capa, 
                         const unsigned char* addr, ia32_instruction& instruct, 
                         ia32_entry** gotit_ret);
   friend unsigned int ia32_decode_operands (const ia32_prefixes& pref, const ia32_entry& gotit, 
@@ -919,19 +901,42 @@ class ia32_instruction
 #define IA32_DECODE_PREFIXES	(1<<0)
 #define IA32_DECODE_MNEMONICS	(1<<1)
 #define IA32_DECODE_OPERANDS	(1<<2)
-#define IA32_DECODE_JMPS	(1<<3)
+#define IA32_DECODE_JMPS	    (1<<3)
 #define IA32_DECODE_MEMACCESS	(1<<4)
 #define IA32_DECODE_CONDITION 	(1<<5)
 
-#define IA32_FULL_DECODER (IA32_DECODE_PREFIXES | IA32_DECODE_MNEMONICS | IA32_DECODE_OPERANDS | IA32_DECODE_JMPS | IA32_DECODE_MEMACCESS | IA32_DECODE_CONDITION)
+#define IA32_FULL_DECODER (IA32_DECODE_PREFIXES \
+        | IA32_DECODE_MNEMONICS \
+        | IA32_DECODE_OPERANDS \
+        | IA32_DECODE_JMPS \
+        | IA32_DECODE_MEMACCESS \
+        | IA32_DECODE_CONDITION)
 #define IA32_SIZE_DECODER 0
 
-COMMON_EXPORT ia32_instruction& ia32_decode(unsigned int capabilities, 
-        const unsigned char* addr, ia32_instruction&);
+/* TODO: documentation*/
+COMMON_EXPORT bool ia32_decode_prefixes(const unsigned char* addr, ia32_instruction& insn);
+
+/**
+ * Decode just the opcode of the given instruction. This implies that
+ * ia32_decode_prefixes has already been called on the given instruction
+ * and addr has been moved past the prefix bytes. Returns zero on success,
+ * non zero otherwise.
+ */
 COMMON_EXPORT int ia32_decode_opcode(unsigned int capa, 
         const unsigned char* addr, ia32_instruction& instruct, 
         ia32_entry** gotit_ret);
 
+/**
+ * Do a complete decoding of the instruction at the given address. This
+ * function calls ia32_decode_prefixes, ia32_decode_opcode and
+ * ia32_decode_operands. Returns zero on success, non zero otherwise.
+ * When there is a decoding failure, the state of the given instruction
+ * is not defined. capabilities is a mask of the above flags (IA32_DECODE_*).
+ * The mask determines what part of the instruction should be decoded.
+ */
+COMMON_EXPORT ia32_instruction& ia32_decode(unsigned int capabilities,
+        const unsigned char* addr, ia32_instruction&);
+
 
 enum dynamic_call_address_mode {
   REGISTER_DIRECT, REGISTER_INDIRECT,