Index: lib/interception/interception_win.cc
===================================================================
--- lib/interception/interception_win.cc
+++ lib/interception/interception_win.cc
@@ -129,14 +129,14 @@
         continue;
     }
 
-    switch (*(unsigned short*)(code + cursor)) {  // NOLINT
+    switch (*(u16*)(code + cursor)) {  // NOLINT
       case 0x5540:  // 40 55 : rex push rbp
       case 0x5340:  // 40 53 : rex push rbx
         cursor += 2;
         continue;
     }
 
-    switch (0x00FFFFFF & *(unsigned int*)(code + cursor)) {
+    switch (0x00FFFFFF & *(u32*)(code + cursor)) {
       case 0xc18b48:    // 48 8b c1 : mov rax, rcx
       case 0xc48b48:    // 48 8b c4 : mov rax, rsp
       case 0xd9f748:    // 48 f7 d9 : neg rcx
@@ -171,14 +171,14 @@
         continue;
     }
 
-    switch (*(unsigned int*)(code + cursor)) {
+    switch (*(u32*)(code + cursor)) {
       case 0x24448b48:  // 48 8b 44 24 XX : mov rax, qword ptr [rsp + 0xXX]
         cursor += 5;
         continue;
     }
 
     // Check first 5 bytes.
-    switch (0xFFFFFFFFFFull & *(unsigned long long*)(code + cursor)) {
+    switch (0xFFFFFFFFFFull & *(u64*)(code + cursor)) {
       case 0x08245c8948:    // 48 89 5c 24 08 : mov QWORD PTR [rsp+0x8], rbx
       case 0x1024748948:    // 48 89 74 24 10 : mov QWORD PTR [rsp+0x10], rsi
         cursor += 5;
@@ -186,7 +186,7 @@
     }
 
     // Check 8 bytes.
-    switch (*(unsigned long long*)(code + cursor)) {
+    switch (*(u64*)(code + cursor)) {
       case 0x90909090909006EBull:  // JMP +6,  6x NOP
         cursor += 8;
         continue;
@@ -201,6 +201,28 @@
   size_t cursor = 0;
   while (cursor < size) {
     switch (code[cursor]) {
+      case '\xE8':  // E8 XX XX XX XX = call <func>
+      case '\xE9':  // E9 XX XX XX XX = jmp <label>
+      case '\xC3':  // C3 = ret
+      case '\xEB':  // EB XX = jmp XX (short jump)
+      case '\x70':  // 7X YY = jx XX (short conditional jump)
+      case '\x71':
+      case '\x72':
+      case '\x73':
+      case '\x74':
+      case '\x75':
+      case '\x76':
+      case '\x77':
+      case '\x78':
+      case '\x79':
+      case '\x7A':
+      case '\x7B':
+      case '\x7C':
+      case '\x7D':
+      case '\x7E':
+      case '\x7F':
+        return 0;
+
       case '\x50':  // push eax
       case '\x51':  // push ecx
       case '\x52':  // push edx
@@ -215,15 +237,15 @@
       case '\x6A':  // 6A XX = push XX
         cursor += 2;
         continue;
-      case '\xE9':  // E9 XX YY ZZ WW = jmp WWZZYYXX
       case '\xB8':  // B8 XX YY ZZ WW = mov eax, WWZZYYXX
         cursor += 5;
         continue;
     }
-    switch (*(unsigned short*)(code + cursor)) {  // NOLINT
+    switch (*(u16*)(code + cursor)) {  // NOLINT
       case 0xFF8B:  // 8B FF = mov edi, edi
       case 0xEC8B:  // 8B EC = mov ebp, esp
       case 0xC033:  // 33 C0 = xor eax, eax
+      case 0xC933:  // 33 C9 = xor ecx, ecx
         cursor += 2;
         continue;
       case 0x458B:  // 8B 45 XX = mov eax, dword ptr [ebp+XXh]
@@ -244,7 +266,7 @@
         cursor += 4;
         continue;
     }
-    switch (0x00FFFFFF & *(unsigned int*)(code + cursor)) {
+    switch (0x00FFFFFF & *(u32*)(code + cursor)) {
       case 0x24448A:  // 8A 44 24 XX = mov eal, dword ptr [esp+XXh]
       case 0x24448B:  // 8B 44 24 XX = mov eax, dword ptr [esp+XXh]
       case 0x244C8B:  // 8B 4C 24 XX = mov ecx, dword ptr [esp+XXh]
@@ -254,7 +276,7 @@
         cursor += 4;
         continue;
     }
-    switch (*(unsigned int *)(code + cursor)) {
+    switch (*(u32*)(code + cursor)) {
       case 0x2444B60F:  // 0F B6 44 24 XX = movzx eax, byte ptr [esp+XXh]
         cursor += 5;
         continue;
Index: lib/interception/tests/interception_win_test.cc
===================================================================
--- lib/interception/tests/interception_win_test.cc
+++ lib/interception/tests/interception_win_test.cc
@@ -27,7 +27,8 @@
 typedef int (*IdentityFunction)(int);
 
 #if !SANITIZER_WINDOWS64
-u8 kIdentityCodeWithPrologue[] = {
+
+const u8 kIdentityCodeWithPrologue[] = {
     0x55,              // push        ebp
     0x8B, 0xEC,        // mov         ebp,esp
     0x8B, 0x45, 0x08,  // mov         eax,dword ptr [ebp + 8]
@@ -35,7 +36,7 @@
     0xC3,              // ret
 };
 
-u8 kIdentityCodeWithPushPop[] = {
+const u8 kIdentityCodeWithPushPop[] = {
     0x55,              // push        ebp
     0x8B, 0xEC,        // mov         ebp,esp
     0x53,              // push        ebx
@@ -47,28 +48,85 @@
     0xC3,              // ret
 };
 
+const u8 kPatchableCode1[] = {
+    0xB8, 0x4B, 0x00, 0x00, 0x00,   // mov eax,4B
+    0x33, 0xC9,                     // xor ecx,ecx
+    0xC3,                           // ret
+};
+
+const u8 kPatchableCode2[] = {
+    0x55,                           // push ebp
+    0x8B, 0xEC,                     // mov ebp,esp
+    0x33, 0xC0,                     // xor eax,eax
+    0x5D,                           // pop ebp
+    0xC3,                           // ret
+};
+
+const u8 kPatchableCode3[] = {
+    0x55,                           // push ebp
+    0x8B, 0xEC,                     // mov ebp,esp
+    0x6A, 0x00,                     // push 0
+    0xE8, 0x3D, 0xFF, 0xFF, 0xFF,   // call <func>
+};
+
+const u8 kUnpatchableCode1[] = {
+    0xC3,                           // ret
+};
+
+const u8 kUnpatchableCode2[] = {
+    0x33, 0xC9,                     // xor ecx,ecx
+    0xC3,                           // ret
+};
+
+const u8 kUnpatchableCode3[] = {
+    0x75, 0xCC,                     // jne <label>
+    0x33, 0xC9,                     // xor ecx,ecx
+    0xC3,                           // ret
+};
+
+const u8 kUnpatchableCode4[] = {
+    0x74, 0xCC,                     // jne <label>
+    0x33, 0xC9,                     // xor ecx,ecx
+    0xC3,                           // ret
+};
+
+const u8 kUnpatchableCode5[] = {
+    0xEB, 0x02,                     // jmp <label>
+    0x33, 0xC9,                     // xor ecx,ecx
+    0xC3,                           // ret
+};
+
+const u8 kUnpatchableCode6[] = {
+    0xE9, 0xCC, 0xCC, 0xCC, 0xCC,   // jmp <label>
+    0x90, 0x90, 0x90, 0x90,
+};
+
+const u8 kUnpatchableCode7[] = {
+    0xE8, 0xCC, 0xCC, 0xCC, 0xCC,   // call <func>
+    0x90, 0x90, 0x90, 0x90,
+};
+
 #endif
 
 // A buffer holding the dynamically generated code under test.
 u8* ActiveCode;
 size_t ActiveCodeLength = 4096;
 
-bool LoadActiveCode(u8* Code, size_t CodeLength, uptr* EntryPoint) {
+template<class T>
+void LoadActiveCode(const T &Code, uptr *EntryPoint) {
   if (ActiveCode == nullptr) {
     ActiveCode =
         (u8*)::VirtualAlloc(nullptr, ActiveCodeLength, MEM_COMMIT | MEM_RESERVE,
                             PAGE_EXECUTE_READWRITE);
-    if (ActiveCode == nullptr) return false;
+    ASSERT_NE(ActiveCode, nullptr);
   }
 
   size_t Position = 0;
   *EntryPoint = (uptr)&ActiveCode[0];
 
   // Copy the function body.
-  for (size_t i = 0; i < CodeLength; ++i)
-  	ActiveCode[Position++] = Code[i];
-
-  return true;
+  for (size_t i = 0; i < sizeof(T); ++i)
+    ActiveCode[Position++] = Code[i];
 }
 
 int InterceptorFunctionCalled;
@@ -96,10 +154,21 @@
   EXPECT_NE(DbgPrint_adddress, isdigit_address);
 }
 
-void TestIdentityFunctionPatching(u8* IdentityCode, size_t IdentityCodeLength) {
+template<class T>
+bool TestFunctionPatching(const T &Code) {
+  uptr Address;
+  int x = sizeof(T);
+
+  LoadActiveCode<T>(Code, &Address);
+  uptr UnusedRealAddress = 0;
+  return OverrideFunction(Address, (uptr)&InterceptorFunction,
+                          &UnusedRealAddress);
+}
+
+template<class T>
+void TestIdentityFunctionPatching(const T &IdentityCode) {
   uptr IdentityAddress;
-  ASSERT_TRUE(
-      LoadActiveCode(IdentityCode, IdentityCodeLength, &IdentityAddress));
+  LoadActiveCode<T>(IdentityCode, &IdentityAddress);
   IdentityFunction Identity = (IdentityFunction)IdentityAddress;
 
   // Validate behavior before dynamic patching.
@@ -129,10 +198,22 @@
 
 #if !SANITIZER_WINDOWS64
 TEST(Interception, OverrideFunction) {
-  TestIdentityFunctionPatching(kIdentityCodeWithPrologue,
-                               sizeof(kIdentityCodeWithPrologue));
-  TestIdentityFunctionPatching(kIdentityCodeWithPushPop,
-                               sizeof(kIdentityCodeWithPushPop));
+  TestIdentityFunctionPatching(kIdentityCodeWithPrologue);
+  TestIdentityFunctionPatching(kIdentityCodeWithPushPop);
+}
+
+TEST(Interception, PatchableFunction) {
+  EXPECT_TRUE(TestFunctionPatching(kPatchableCode1));
+  EXPECT_TRUE(TestFunctionPatching(kPatchableCode2));
+  EXPECT_TRUE(TestFunctionPatching(kPatchableCode3));
+
+  EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode1));
+  EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode2));
+  EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode3));
+  EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode4));
+  EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode5));
+  EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode6));
+  EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode7));
 }
 #endif