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Enhance stack protector for calling no return function 

Reviewed By: LuoYuanke, WangPengfei, lebedev.ri

Differential Revision: https://reviews.llvm.org/D138774
This commit is contained in:
Xiang1 Zhang 2022-11-28 15:02:04 +08:00
parent fc743f034a
commit 416e8c6ad5
3 changed files with 243 additions and 7 deletions
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26
llvm/lib/CodeGen/StackProtector.cpp
View File

@ -414,11 +414,11 @@ static Value *getStackGuard(const TargetLoweringBase *TLI, Module *M,
///
/// Returns true if the platform/triple supports the stackprotectorcreate pseudo
/// node.
static bool CreatePrologue(Function *F, Module *M, ReturnInst *RI,
static bool CreatePrologue(Function *F, Module *M, Instruction *CheckLoc,
const TargetLoweringBase *TLI, AllocaInst *&AI) {
bool SupportsSelectionDAGSP = false;
IRBuilder<> B(&F->getEntryBlock().front());
PointerType *PtrTy = Type::getInt8PtrTy(RI->getContext());
PointerType *PtrTy = Type::getInt8PtrTy(CheckLoc->getContext());
AI = B.CreateAlloca(PtrTy, nullptr, "StackGuardSlot");
Value *GuardSlot = getStackGuard(TLI, M, B, &SupportsSelectionDAGSP);
@ -443,14 +443,27 @@ bool StackProtector::InsertStackProtectors() {
AllocaInst *AI = nullptr; // Place on stack that stores the stack guard.
for (BasicBlock &BB : llvm::make_early_inc_range(*F)) {
ReturnInst *RI = dyn_cast<ReturnInst>(BB.getTerminator());
if (!RI)
Instruction *CheckLoc = dyn_cast<ReturnInst>(BB.getTerminator());
if (!CheckLoc) {
for (auto &Inst : BB) {
auto *CB = dyn_cast<CallBase>(&Inst);
if (!CB)
continue;
if (!CB->doesNotReturn())
continue;
// Do stack check before non-return calls (e.g: __cxa_throw)
CheckLoc = CB;
break;
}
}
if (!CheckLoc)
continue;
// Generate prologue instrumentation if not already generated.
if (!HasPrologue) {
HasPrologue = true;
SupportsSelectionDAGSP &= CreatePrologue(F, M, RI, TLI, AI);
SupportsSelectionDAGSP &= CreatePrologue(F, M, CheckLoc, TLI, AI);
}
// SelectionDAG based code generation. Nothing else needs to be done here.
@ -476,8 +489,7 @@ bool StackProtector::InsertStackProtectors() {
// verifier guarantees that a tail call is either directly before the
// return or with a single correct bitcast of the return value in between so
// we don't need to worry about many situations here.
Instruction *CheckLoc = RI;
Instruction *Prev = RI->getPrevNonDebugInstruction();
Instruction *Prev = CheckLoc->getPrevNonDebugInstruction();
if (Prev && isa<CallInst>(Prev) && cast<CallInst>(Prev)->isTailCall())
CheckLoc = Prev;
else if (Prev) {

30
llvm/test/CodeGen/X86/stack-protector-2.ll
View File

@ -192,4 +192,34 @@ define dso_local void @bar_nossp(i64 %0) {
ret void
}
; Check stack protect for noreturn call
define dso_local i32 @foo_no_return(i32 %0) #1 {
; CHECK-LABEL: @foo_no_return
entry:
%cmp = icmp sgt i32 %0, 4
br i1 %cmp, label %if.then, label %if.end
; CHECK: if.then: ; preds = %entry
; CHECK-NEXT: %StackGuard1 = load volatile i8*, i8* addrspace(257)* inttoptr (i32 40 to i8* addrspace(257)*), align 8
; CHECK-NEXT: %1 = load volatile i8*, i8** %StackGuardSlot, align 8
; CHECK-NEXT: %2 = icmp eq i8* %StackGuard1, %1
; CHECK-NEXT: br i1 %2, label %SP_return, label %CallStackCheckFailBlk
; CHECK: SP_return: ; preds = %if.then
; CHECK-NEXT: %call = call i32 @foo_no_return(i32 1)
; CHECK-NEXT: br label %return
; CHECK: if.end: ; preds = %entry
; CHECK-NEXT: br label %return
if.then: ; preds = %entry
%call = call i32 @foo_no_return(i32 1)
br label %return
if.end: ; preds = %entry
br label %return
return: ; preds = %if.end, %if.then
ret i32 0
}
attributes #0 = { sspstrong }
attributes #1 = { noreturn sspreq}

194
llvm/test/CodeGen/X86/stack-protector-no-return.ll Normal file
View File

@ -0,0 +1,194 @@
; RUN: llc %s -mtriple=x86_64-unknown-linux-gnu -o - | FileCheck %s
$__clang_call_terminate = comdat any
@_ZTIi = external dso_local constant i8*
@.str = private unnamed_addr constant [5 x i8] c"win\0A\00", align 1
; Function Attrs: mustprogress noreturn sspreq uwtable
define dso_local void @_Z7catchesv() local_unnamed_addr #0 personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
; CHECK-LABEL: _Z7catchesv:
; CHECK: # %bb.0: # %entry
; CHECK: movq %fs:40, %rax
; CHECK-NEXT: movq %rax, 8(%rsp)
entry:
%exception = tail call i8* @__cxa_allocate_exception(i64 4) #8
%0 = bitcast i8* %exception to i32*
store i32 1, i32* %0, align 16
invoke void @__cxa_throw(i8* nonnull %exception, i8* bitcast (i8** @_ZTIi to i8*), i8* null) #9
to label %unreachable unwind label %lpad
; CHECK: callq __cxa_allocate_exception
; CHECK-NEXT: movl $1, (%rax)
; CHECK-NEXT: movq %fs:40, %rcx
; CHECK-NEXT: cmpq 8(%rsp), %rcx
; CHECK-NEXT: jne .LBB0_12
; CHECK-NEXT: # %bb.1: # %SP_return
; CHECK-NEXT: .Ltmp0:
; CHECK-NEXT: movl $_ZTIi, %esi
; CHECK-NEXT: movq %rax, %rdi
; CHECK-NEXT: xorl %edx, %edx
; CHECK-NEXT: callq __cxa_throw
lpad: ; preds = %entry
%1 = landingpad { i8*, i32 }
catch i8* null
%2 = extractvalue { i8*, i32 } %1, 0
%3 = tail call i8* @__cxa_begin_catch(i8* %2) #8
%call = invoke i64 @write(i32 noundef 1, i8* noundef getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0), i64 noundef 4)
to label %invoke.cont unwind label %lpad1
; CHECK: callq __cxa_begin_catch
; CHECK-NEXT: .Ltmp3:
; CHECK-NEXT: movl $.L.str, %esi
; CHECK-NEXT: movl $4, %edx
; CHECK-NEXT: movl $1, %edi
; CHECK-NEXT: callq write
invoke.cont: ; preds = %lpad
invoke void @_exit(i32 noundef 1) #9
to label %invoke.cont2 unwind label %lpad1
; CHECK: # %bb.3: # %invoke.cont
; CHECK-NEXT: movq %fs:40, %rax
; CHECK-NEXT: cmpq 8(%rsp), %rax
; CHECK-NEXT: jne .LBB0_12
; CHECK-NEXT: # %bb.4: # %SP_return3
; CHECK-NEXT: .Ltmp5:
; CHECK-NEXT: movl $1, %edi
; CHECK-NEXT: callq _exit
invoke.cont2: ; preds = %invoke.cont
unreachable
lpad1: ; preds = %invoke.cont, %lpad
%4 = landingpad { i8*, i32 }
cleanup
invoke void @__cxa_end_catch()
to label %eh.resume unwind label %terminate.lpad
; CHECK: .LBB0_6: # %lpad1
; CHECK-NEXT: .Ltmp7:
; CHECK-NEXT: movq %rax, %rbx
; CHECK-NEXT: .Ltmp8:
; CHECK-NEXT: callq __cxa_end_catch
eh.resume: ; preds = %lpad1
resume { i8*, i32 } %4
; CHECK: # %bb.7: # %eh.resume
; CHECK-NEXT: movq %fs:40, %rax
; CHECK-NEXT: cmpq 8(%rsp), %rax
; CHECK-NEXT: jne .LBB0_12
; CHECK-NEXT: # %bb.8: # %SP_return6
; CHECK-NEXT: movq %rbx, %rdi
; CHECK-NEXT: callq _Unwind_Resume@PLT
terminate.lpad: ; preds = %lpad1
%5 = landingpad { i8*, i32 }
catch i8* null
%6 = extractvalue { i8*, i32 } %5, 0
tail call void @__clang_call_terminate(i8* %6) #10
unreachable
; CHECK: .LBB0_9: # %terminate.lpad
; CHECK: movq %fs:40, %rcx
; CHECK-NEXT: cmpq 8(%rsp), %rcx
; CHECK-NEXT: jne .LBB0_12
; CHECK-NEXT: # %bb.10: # %SP_return9
; CHECK-NEXT: movq %rax, %rdi
; CHECK-NEXT: callq __clang_call_terminate
; CHECK: .LBB0_12: # %CallStackCheckFailBlk
; CHECK-NEXT: callq __stack_chk_fail@PLT
unreachable: ; preds = %entry
unreachable
}
; Function Attrs: nofree
declare dso_local noalias i8* @__cxa_allocate_exception(i64) local_unnamed_addr #1
; Function Attrs: nofree noreturn
declare dso_local void @__cxa_throw(i8*, i8*, i8*) local_unnamed_addr #2
declare dso_local i32 @__gxx_personality_v0(...)
; Function Attrs: nofree
declare dso_local i8* @__cxa_begin_catch(i8*) local_unnamed_addr #1
; Function Attrs: nofree
declare dso_local noundef i64 @write(i32 noundef, i8* nocapture noundef readonly, i64 noundef) local_unnamed_addr #3
; Function Attrs: nofree noreturn
declare dso_local void @_exit(i32 noundef) local_unnamed_addr #4
; Function Attrs: nofree
declare dso_local void @__cxa_end_catch() local_unnamed_addr #1
; Function Attrs: noinline noreturn nounwind
define linkonce_odr hidden void @__clang_call_terminate(i8* %0) local_unnamed_addr #5 comdat {
%2 = tail call i8* @__cxa_begin_catch(i8* %0) #8
tail call void @_ZSt9terminatev() #10
unreachable
}
; Function Attrs: nofree noreturn nounwind
declare dso_local void @_ZSt9terminatev() local_unnamed_addr #6
; Function Attrs: mustprogress nofree sspreq uwtable
define dso_local void @_Z4vulni(i32 noundef %op) local_unnamed_addr #7 {
; CHECK-LABEL: _Z4vulni:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: pushq %rax
; CHECK-NEXT: .cfi_def_cfa_offset 16
; CHECK-NEXT: movq %fs:40, %rax
; CHECK-NEXT: movq %rax, (%rsp)
; CHECK-NEXT: cmpl $1, %edi
; CHECK-NEXT: je .LBB2_1
; CHECK-NEXT: # %bb.3: # %if.end
; CHECK-NEXT: movq %fs:40, %rax
; CHECK-NEXT: cmpq (%rsp), %rax
; CHECK-NEXT: jne .LBB2_5
; CHECK-NEXT: # %bb.4: # %SP_return3
; CHECK-NEXT: popq %rax
; CHECK-NEXT: .cfi_def_cfa_offset 8
; CHECK-NEXT: retq
; CHECK-NEXT: .LBB2_1: # %if.then
; CHECK-NEXT: .cfi_def_cfa_offset 16
; CHECK-NEXT: movl $4, %edi
; CHECK-NEXT: callq __cxa_allocate_exception
; CHECK-NEXT: movl $1, (%rax)
; CHECK-NEXT: movq %fs:40, %rcx
; CHECK-NEXT: cmpq (%rsp), %rcx
; CHECK-NEXT: jne .LBB2_5
; CHECK-NEXT: # %bb.2: # %SP_return
; CHECK-NEXT: movl $_ZTIi, %esi
; CHECK-NEXT: movq %rax, %rdi
; CHECK-NEXT: xorl %edx, %edx
; CHECK-NEXT: callq __cxa_throw
; CHECK-NEXT: .LBB2_5: # %CallStackCheckFailBlk2
; CHECK-NEXT: callq __stack_chk_fail@PLT
entry:
%cmp = icmp eq i32 %op, 1
br i1 %cmp, label %if.then, label %if.end
if.then: ; preds = %entry
%exception = tail call i8* @__cxa_allocate_exception(i64 4) #8
%0 = bitcast i8* %exception to i32*
store i32 1, i32* %0, align 16
tail call void @__cxa_throw(i8* %exception, i8* bitcast (i8** @_ZTIi to i8*), i8* null) #9
unreachable
if.end: ; preds = %entry
ret void
}
attributes #0 = { mustprogress noreturn sspreq uwtable }
attributes #1 = { nofree }
attributes #2 = { nofree noreturn }
attributes #3 = { nofree }
attributes #4 = { nofree noreturn }
attributes #5 = { noinline noreturn nounwind }
attributes #6 = { nofree noreturn nounwind }
attributes #7 = { mustprogress nofree sspreq uwtable }
attributes #8 = { nounwind }
attributes #9 = { noreturn }
attributes #10 = { noreturn nounwind }