llvm-6502/test/CodeGen/X86/seh-safe-div.ll
Reid Kleckner f77571aeac Add a Windows EH preparation pass that zaps resumes
If the personality is not a recognized MSVC personality function, this
pass delegates to the dwarf EH preparation pass. This chaining supports
people on *-windows-itanium or *-windows-gnu targets.

Currently this recognizes some personalities used by MSVC and turns
resume instructions into traps to avoid link errors.  Even if cleanups
are not used in the source program, LLVM requires the frontend to emit a
code path that resumes unwinding after an exception.  Clang does this,
and we get unreachable resume instructions. PR20300 covers cleaning up
these unreachable calls to resume.

Reviewers: majnemer

Differential Revision: http://reviews.llvm.org/D7216

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227405 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-29 00:41:44 +00:00

198 lines
5.7 KiB
LLVM

; 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()