llvm-project/llvm/test/CodeGen/X86/seh-safe-div.ll

; RUN: llc -mtriple x86_64-pc-windows-msvc < %s | FileCheck %s

; This test case is also intended to be run manually as a complete functional
; test. It should link, print something, and exit zero rather than crashing.
; It is the hypothetical lowering of a C source program that looks like:
;
;   int safe_div(int *n, int *d) {
;     int r;
;     __try {
;       __try {
;         r = *n / *d;
;       } __except(GetExceptionCode() == EXCEPTION_ACCESS_VIOLATION) {
;         puts("EXCEPTION_ACCESS_VIOLATION");
;         r = -1;
;       }
;     } __except(GetExceptionCode() == EXCEPTION_INT_DIVIDE_BY_ZERO) {
;       puts("EXCEPTION_INT_DIVIDE_BY_ZERO");
;       r = -2;
;     }
;     return r;
;   }

@str1 = internal constant [27 x i8] c"EXCEPTION_ACCESS_VIOLATION\00"
@str2 = internal constant [29 x i8] c"EXCEPTION_INT_DIVIDE_BY_ZERO\00"

define i32 @safe_div(i32* %n, i32* %d) {
entry:
  %r = alloca i32, align 4
  invoke void @try_body(i32* %r, i32* %n, i32* %d)
          to label %__try.cont unwind label %lpad

lpad:
  %vals = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__C_specific_handler to i8*)
          catch i8* bitcast (i32 (i8*, i8*)* @safe_div_filt0 to i8*)
          catch i8* bitcast (i32 (i8*, i8*)* @safe_div_filt1 to i8*)
  %ehptr = extractvalue { i8*, i32 } %vals, 0
  %sel = extractvalue { i8*, i32 } %vals, 1
  %filt0_val = call i32 @llvm.eh.typeid.for(i8* bitcast (i32 (i8*, i8*)* @safe_div_filt0 to i8*))
  %is_filt0 = icmp eq i32 %sel, %filt0_val
  br i1 %is_filt0, label %handler0, label %eh.dispatch1

eh.dispatch1:
  %filt1_val = call i32 @llvm.eh.typeid.for(i8* bitcast (i32 (i8*, i8*)* @safe_div_filt1 to i8*))
  %is_filt1 = icmp eq i32 %sel, %filt1_val
  br i1 %is_filt1, label %handler1, label %eh.resume

handler0:
  call void @puts(i8* getelementptr ([27 x i8]* @str1, i32 0, i32 0))
  store i32 -1, i32* %r, align 4
  br label %__try.cont

handler1:
  call void @puts(i8* getelementptr ([29 x i8]* @str2, i32 0, i32 0))
  store i32 -2, i32* %r, align 4
  br label %__try.cont

eh.resume:
  resume { i8*, i32 } %vals

__try.cont:
  %safe_ret = load i32* %r, align 4
  ret i32 %safe_ret
}

; Normal path code

; CHECK: {{^}}safe_div:
; CHECK: .seh_proc safe_div
; CHECK: .seh_handler __C_specific_handler, @unwind, @except
; CHECK: .Ltmp0:
; CHECK: leaq [[rloc:.*\(%rsp\)]], %rcx
; CHECK: callq try_body
; CHECK-NEXT: .Ltmp1
; CHECK: .LBB0_7:
; CHECK: movl [[rloc]], %eax
; CHECK: retq

; Landing pad code

; CHECK: .Ltmp3:
; CHECK: movl $1, %[[sel:[a-z]+]]
; CHECK: .Ltmp4
; CHECK: movl $2, %[[sel]]
; CHECK: .L{{.*}}:
; CHECK: cmpl $1, %[[sel]]

; CHECK: # %handler0
; CHECK: callq puts
; CHECK: movl $-1, [[rloc]]
; CHECK: jmp .LBB0_7

; CHECK: cmpl $2, %[[sel]]

; CHECK: # %handler1
; CHECK: callq puts
; CHECK: movl $-2, [[rloc]]
; CHECK: jmp .LBB0_7

; FIXME: EH preparation should eliminate the 'resume' instr and we should not do
; the previous 'cmp;jeq'.
; CHECK-NOT: _Unwind_Resume
; CHECK: ud2

; CHECK: .seh_handlerdata
; CHECK: .long 2
; CHECK: .long .Ltmp0@IMGREL
; CHECK: .long .Ltmp1@IMGREL+1
; CHECK: .long safe_div_filt0@IMGREL
; CHECK: .long .Ltmp3@IMGREL
; CHECK: .long .Ltmp0@IMGREL
; CHECK: .long .Ltmp1@IMGREL+1
; CHECK: .long safe_div_filt1@IMGREL
; CHECK: .long .Ltmp4@IMGREL
; CHECK: .text
; CHECK: .seh_endproc


define void @try_body(i32* %r, i32* %n, i32* %d) {
entry:
  %0 = load i32* %n, align 4
  %1 = load i32* %d, align 4
  %div = sdiv i32 %0, %1
  store i32 %div, i32* %r, align 4
  ret void
}

; The prototype of these filter functions is:
; int filter(EXCEPTION_POINTERS *eh_ptrs, void *rbp);

; The definition of EXCEPTION_POINTERS is:
;   typedef struct _EXCEPTION_POINTERS {
;     EXCEPTION_RECORD *ExceptionRecord;
;     CONTEXT          *ContextRecord;
;   } EXCEPTION_POINTERS;

; The definition of EXCEPTION_RECORD is:
;   typedef struct _EXCEPTION_RECORD {
;     DWORD ExceptionCode;
;     ...
;   } EXCEPTION_RECORD;

; The exception code can be retreived with two loads, one for the record
; pointer and one for the code.  The values of local variables can be
; accessed via rbp, but that would require additional not yet implemented LLVM
; support.

define i32 @safe_div_filt0(i8* %eh_ptrs, i8* %rbp) {
  %eh_ptrs_c = bitcast i8* %eh_ptrs to i32**
  %eh_rec = load i32** %eh_ptrs_c
  %eh_code = load i32* %eh_rec
  ; EXCEPTION_ACCESS_VIOLATION = 0xC0000005
  %cmp = icmp eq i32 %eh_code, 3221225477
  %filt.res = zext i1 %cmp to i32
  ret i32 %filt.res
}

define i32 @safe_div_filt1(i8* %eh_ptrs, i8* %rbp) {
  %eh_ptrs_c = bitcast i8* %eh_ptrs to i32**
  %eh_rec = load i32** %eh_ptrs_c
  %eh_code = load i32* %eh_rec
  ; EXCEPTION_INT_DIVIDE_BY_ZERO = 0xC0000094
  %cmp = icmp eq i32 %eh_code, 3221225620
  %filt.res = zext i1 %cmp to i32
  ret i32 %filt.res
}

@str_result = internal constant [21 x i8] c"safe_div result: %d\0A\00"

define i32 @main() {
  %d.addr = alloca i32, align 4
  %n.addr = alloca i32, align 4

  store i32 10, i32* %n.addr, align 4
  store i32 2, i32* %d.addr, align 4
  %r1 = call i32 @safe_div(i32* %n.addr, i32* %d.addr)
  call void (i8*, ...)* @printf(i8* getelementptr ([21 x i8]* @str_result, i32 0, i32 0), i32 %r1)

  store i32 10, i32* %n.addr, align 4
  store i32 0, i32* %d.addr, align 4
  %r2 = call i32 @safe_div(i32* %n.addr, i32* %d.addr)
  call void (i8*, ...)* @printf(i8* getelementptr ([21 x i8]* @str_result, i32 0, i32 0), i32 %r2)

  %r3 = call i32 @safe_div(i32* %n.addr, i32* null)
  call void (i8*, ...)* @printf(i8* getelementptr ([21 x i8]* @str_result, i32 0, i32 0), i32 %r3)
  ret i32 0
}

define void @_Unwind_Resume() {
  call void @abort()
  unreachable
}

declare i32 @__C_specific_handler(...)
declare i32 @llvm.eh.typeid.for(i8*) readnone nounwind
declare void @puts(i8*)
declare void @printf(i8*, ...)
declare void @abort()