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• Stack frame: A fragment of the stack segment used by a function. Usually contains function arguments, return-to-caller address, saved registers, local variables and other data specific to this function. On x86 (and most other architectures) caller and callee stack frames are contiguous.
• Frame pointer: A register or other variable that points to a fixed location inside the stack frame. Usually all data inside the stack frame is addressed relative to the frame pointer. On x86 it's usually ebp and it usually points just below the return address.
• Object: An instance of a (C++) class.
• Unwindable Object: A local object with auto storage-class specifier that is allocated on the stack and needs to be destructed when it goes out of scope.
• Stack UInwinding: Automatic destruction of such objects that happens when the control leaves the scope due to an exception.

• SEH exceptions (from "Structured Exception Handling"). Also known as Win32 or system exceptions. These are exhaustively covered in the famous Matt Pietrek article[1]. They are the only exceptions available to C programs. The compiler-level support includes keywords __try, __except, __finally and a few others.
• C++ exceptions (sometimes referred to as "EH"). Implemented on top of SEH, C++ exceptions allow throwing and catching of arbitrary types. A very important feature of C++ is automatic stack unwinding during exception processing, and MSVC uses a pretty complex underlying framework to ensure that it works properly in all cases.

    ...
    Local variables
    Other saved registers
    Saved ebp
    Return address
    Function arguments
    ...

SEH3 Stack Layout

    struct _SCOPETABLE_ENTRY {
      DWORD EnclosingLevel;
      void* FilterFunc;
      void* HandlerFunc;
    }

SEH4 Stack Layout

    struct _EH4_SCOPETABLE {
        DWORD GSCookieOffset;
        DWORD GSCookieXOROffset;
        DWORD EHCookieOffset;
        DWORD EHCookieXOROffset;
        _EH4_SCOPETABLE_RECORD ScopeRecord[1];
    };

    struct _EH4_SCOPETABLE_RECORD {
        DWORD EnclosingLevel;
        long (*FilterFunc)();
            union {
            void (*HandlerAddress)();
            void (*FinallyFunc)();
        };
    };

C++ EH Stack Layout

     (VC7+)
    mov eax, OFFSET __ehfuncinfo
    jmp ___CxxFrameHandler

    struct FuncInfo {
      // compiler version.
      // 0x19930520: up to VC6, 0x19930521: VC7.x(2002-2003), 0x19930522: VC8 (2005)
      DWORD magicNumber;

      // number of entries in unwind table
      int maxState;

      // table of unwind destructors
      UnwindMapEntry* pUnwindMap;

      // number of try blocks in the function
      DWORD nTryBlocks;

      // mapping of catch blocks to try blocks
      TryBlockMapEntry* pTryBlockMap;

      // not used on x86
      DWORD nIPMapEntries;

      // not used on x86
      void* pIPtoStateMap;

      // VC7+ only, expected exceptions list (function "throw" specifier) 
      ESTypeList* pESTypeList;

      // VC8+ only, bit 0 set if function was compiled with /EHs
      int EHFlags;
    };

    struct UnwindMapEntry {
      int toState;        // target state
      void (*action)();   // action to perform (unwind funclet address)
    };

    struct TryBlockMapEntry {
      int tryLow;
      int tryHigh;    // this try {} covers states ranging from tryLow to tryHigh
      int catchHigh;  // highest state inside catch handlers of this try
      int nCatches;   // number of catch handlers
      HandlerType* pHandlerArray; //catch handlers table
    };

struct HandlerType {
  // 0x01: const, 0x02: volatile, 0x08: reference
  DWORD adjectives;

  // RTTI descriptor of the exception type. 0=any (ellipsis)
  TypeDescriptor* pType;

  // ebp-based offset of the exception object in the function stack.
  // 0 = no object (catch by type)
  int dispCatchObj;

  // address of the catch handler code.
  // returns address where to continues execution (i.e. code after the try block)
  void* addressOfHandler;
};

    struct ESTypeList {
      // number of entries in the list
      int nCount;

      // list of exceptions; it seems only pType field in HandlerType is used
      HandlerType* pTypeArray;
    };

struct TypeDescriptor {
  // vtable of type_info class
  const void * pVFTable;

  // used to keep the demangled name returned by type_info::name()
  void* spare;

  // mangled type name, e.g. ".H" = "int", ".?AUA@@" = "struct A", ".?AVA@@" = "class A"
  char name[0];
};

    struct ThrowInfo {
      // 0x01: const, 0x02: volatile
      DWORD attributes;

      // exception destructor
      void (*pmfnUnwind)();

      // forward compatibility handler
      int (*pForwardCompat)();

      // list of types that can catch this exception.
      // i.e. the actual type and all its ancestors.
      CatchableTypeArray* pCatchableTypeArray;
    };

    struct CatchableTypeArray {
      // number of entries in the following array
      int nCatchableTypes; 
      CatchableType* arrayOfCatchableTypes[0];
    };

    struct CatchableType {
      // 0x01: simple type (can be copied by memmove), 0x02: can be caught by reference only, 0x04: has virtual bases
      DWORD properties;

      // see above
      TypeDescriptor* pType;

      // how to cast the thrown object to this type
      PMD thisDisplacement;

      // object size
      int sizeOrOffset;

      // copy constructor address
      void (*copyFunction)();
    };

    // Pointer-to-member descriptor.
    struct PMD {
      // member offset
      int mdisp;

      // offset of the vbtable (-1 if not a virtual base)
      int pdisp;

      // offset to the displacement value inside the vbtable
      int vdisp;
    };

    ...
    Saved edi
    Saved esi
    Saved ebx
    Next SEH frame
    Current SEH handler (__except_handler2)
    Pointer to the scopetable
    Try level
    Saved ebp (of this function)
    Exception pointers
    Local variables
    Saved ESP
    Local variables
    Callee EBP
    Return address
    Function arguments
    ...

func1           proc near

_excCode        = dword ptr -28h
buf             = byte ptr -24h
_saved_esp      = dword ptr -18h
_exception_info = dword ptr -14h
_next           = dword ptr -10h
_handler        = dword ptr -0Ch
_scopetable     = dword ptr -8
_trylevel       = dword ptr -4
str             = dword ptr  8

  push    ebp
  mov     ebp, esp
  push    -1
  push    offset _func1_scopetable
  push    offset _except_handler3
  mov     eax, large fs:0
  push    eax
  mov     large fs:0, esp
  add     esp, -18h
  push    ebx
  push    esi
  push    edi

  ; --- end of prolog ---

  mov     [ebp+_trylevel], 0 ;trylevel -1 -> 0: beginning of try block 0
  mov     [ebp+_trylevel], 1 ;trylevel 0 -> 1: beginning of try block 1
  mov     large dword ptr ds:123, 456
  mov     [ebp+_trylevel], 0 ;trylevel 1 -> 0: end of try block 1
  jmp     short _endoftry1

_func1_filter1:                         ; __except() filter of try block 1
  mov     ecx, [ebp+_exception_info]
  mov     edx, [ecx+EXCEPTION_POINTERS.ExceptionRecord]
  mov     eax, [edx+EXCEPTION_RECORD.ExceptionCode]
  mov     [ebp+_excCode], eax
  mov     ecx, [ebp+_excCode]
  xor     eax, eax
  cmp     ecx, EXCEPTION_ACCESS_VIOLATION
  setz    al
  retn

_func1_handler1:                        ; beginning of handler for try block 1
  mov     esp, [ebp+_saved_esp]
  push    offset aAccessViolatio ; "Access violation"
  call    _printf
  add     esp, 4
  mov     [ebp+_trylevel], 0 ;trylevel 1 -> 0: end of try block 1

_endoftry1:
  mov     edx, [ebp+str]
  push    edx
  lea     eax, [ebp+buf]
  push    eax
  call    _strcpy
  add     esp, 8
  mov     [ebp+_trylevel], -1 ; trylevel 0 -> -1: end of try block 0
  call    _func1_handler0     ; execute __finally of try block 0
  jmp     short _endoftry0

_func1_handler0:                        ; __finally handler of try block 0
  push    offset aInFinally ; "in finally"
  call    _puts
  add     esp, 4
  retn

_endoftry0:
  ; --- epilog ---
  mov     ecx, [ebp+_next]
  mov     large fs:0, ecx
  pop     edi
  pop     esi
  pop     ebx
  mov     esp, ebp
  pop     ebp
  retn
func1           endp

_func1_scopetable
  ;try block 0
  dd -1                      ;EnclosingLevel
  dd 0                       ;FilterFunc
  dd offset _func1_handler0  ;HandlerFunc

  ;try block 1
  dd 0                       ;EnclosingLevel
  dd offset _func1_filter1   ;FilterFunc
  dd offset _func1_handler1  ;HandlerFunc

    void func1 (char* str)
    {
      char buf[12];
      __try // try block 0
      {
         __try // try block 1
         {
           *(int*)123=456;
         }
         __except(GetExceptCode() == EXCEPTION_ACCESS_VIOLATION)
         {
            printf("Access violation");
         }
         strcpy(buf,str);
      }
      __finally
      {
         puts("in finally");
      }
    }

func1           proc near

_a1             = dword ptr -24h
_exc            = dword ptr -20h
e               = dword ptr -1Ch
a2              = dword ptr -18h
a1              = dword ptr -14h
_saved_esp      = dword ptr -10h
_next           = dword ptr -0Ch
_handler        = dword ptr -8
_state          = dword ptr -4

  push    ebp
  mov     ebp, esp
  push    0FFFFFFFFh
  push    offset func1_ehhandler
  mov     eax, large fs:0
  push    eax
  mov     large fs:0, esp
  push    ecx
  sub     esp, 14h
  push    ebx
  push    esi
  push    edi
  mov     [ebp+_saved_esp], esp

  ; --- end of prolog ---

  lea     ecx, [ebp+a1]
  call    A::A(void)
  mov     [ebp+_state], 0          ; state -1 -> 0: a1 constructed
  mov     [ebp+a1], 1              ; a1.m1 = 1
  mov     byte ptr [ebp+_state], 1 ; state 0 -> 1: try {
  lea     ecx, [ebp+a2]
  call    A::A(void)
  mov     [ebp+_a1], eax
  mov     byte ptr [ebp+_state], 2 ; state 2: a2 constructed
  mov     [ebp+a2], 2              ; a2.m1 = 2
  mov     eax, [ebp+a1]
  cmp     eax, [ebp+a2]            ; a1.m1 == a2.m1?
  jnz     short loc_40109F
  mov     [ebp+_exc], offset aAbc  ; _exc = "abc"
  push    offset __TI1?PAD         ; char *
  lea     ecx, [ebp+_exc]
  push    ecx
  call    _CxxThrowException       ; throw "abc";

loc_40109F:
  mov     byte ptr [ebp+_state], 1 ; state 2 -> 1: destruct a2
  lea     ecx, [ebp+a2]
  call    A::~A(void)
  jmp     short func1_try0end

; catch (char * e)
func1_try0handler_pchar:
  mov     edx, [ebp+e]
  push    edx
  push    offset aCaughtS ; "Caught %s\n"
  call    ds:printf       ;
  add     esp, 8
  mov     eax, offset func1_try0end
  retn

; catch (...)
func1_try0handler_ellipsis:
  push    offset aCaught___ ; "Caught ...\n"
  call    ds:printf
  add     esp, 4
  mov     eax, offset func1_try0end
  retn

func1_try0end:
  mov     [ebp+_state], 0          ; state 1 -> 0: }//try
  push    offset aAfterTry ; "after try\n"
  call    ds:printf
  add     esp, 4
  mov     [ebp+_state], -1         ; state 0 -> -1: destruct a1
  lea     ecx, [ebp+a1]
  call    A::~A(void)
  ; --- epilog ---
  mov     ecx, [ebp+_next]
  mov     large fs:0, ecx
  pop     edi
  pop     esi
  pop     ebx
  mov     esp, ebp
  pop     ebp
  retn
func1           endp

func1_ehhandler proc near
  mov     eax, offset func1_funcinfo
  jmp     __CxxFrameHandler
func1_ehhandler endp

func1_funcinfo
  dd 19930520h            ; magicNumber
  dd 4                    ; maxState
  dd offset func1_unwindmap ; pUnwindMap
  dd 1                    ; nTryBlocks
  dd offset func1_trymap  ; pTryBlockMap
  dd 0                    ; nIPMapEntries
  dd 0                    ; pIPtoStateMap
  dd 0                    ; pESTypeList

func1_unwindmap
  dd -1
  dd offset func1_unwind_1tobase ; action
  dd 0                    ; toState
  dd 0                    ; action
  dd 1                    ; toState
  dd offset func1_unwind_2to1 ; action
  dd 0                    ; toState
  dd 0                    ; action

func1_trymap
  dd 1                    ; tryLow
  dd 2                    ; tryHigh
  dd 3                    ; catchHigh
  dd 2                    ; nCatches
  dd offset func1_tryhandlers_0 ; pHandlerArray
  dd 0

func1_tryhandlers_0
dd 0                    ; adjectives
dd offset char * `RTTI Type Descriptor' ; pType
dd -1Ch                 ; dispCatchObj
dd offset func1_try0handler_pchar ; addressOfHandler
dd 0                    ; adjectives
dd 0                    ; pType
dd 0                    ; dispCatchObj
dd offset func1_try0handler_ellipsis ; addressOfHandler

func1_unwind_1tobase proc near
a1 = byte ptr -14h
  lea     ecx, [ebp+a1]
  call    A::~A(void)
  retn
func1_unwind_1tobase endp

func1_unwind_2to1 proc near
a2 = byte ptr -18h
  lea     ecx, [ebp+a2]
  call    A::~A(void)
  retn
func1_unwind_2to1 endp

• state 3 -> state 0 (no action)
• state 2 -> state 1 (destruct a2)
• state 1 -> state 0 (no action)
• state 0 -> state -1 (destruct a1)

    void func1 ()
    {
      A a1;
      a1.m1 = 1;
      try {
        A a2;
        a2.m1 = 2;
        if (a1.m1 == a1.m2) throw "abc";
      }
      catch(char* e)
      {
        printf("Caught %s\n",e);
      }
      catch(...)
      {
        printf("Caught ...\n");
      }
      printf("after try\n");
    }

• VC8 CRT debug information (many structure definitions)
• VC8 assembly output (/FAs)
• VC8 WinCE CRT source