[llvm] r258746 - [cfi] Cross-DSO CFI diagnostic mode (LLVM part).

[Evgeniy Stepanov via llvm-commits]

Author: eugenis
Date: Mon Jan 25 17:35:03 2016
New Revision: 258746

URL: http://llvm.org/viewvc/llvm-project?rev=258746&view=rev
Log:
[cfi] Cross-DSO CFI diagnostic mode (LLVM part).

* __cfi_check gets a 3rd argument: ubsan handler data
* Instead of trapping on failure, call __cfi_check_fail which must be
  present in the module (generated in the frontend).

Modified:
    llvm/trunk/lib/Transforms/IPO/CrossDSOCFI.cpp
    llvm/trunk/test/Transforms/CrossDSOCFI/basic.ll

Modified: llvm/trunk/lib/Transforms/IPO/CrossDSOCFI.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/CrossDSOCFI.cpp?rev=258746&r1=258745&r2=258746&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/CrossDSOCFI.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/CrossDSOCFI.cpp Mon Jan 25 17:35:03 2016
@@ -110,31 +110,30 @@ void CrossDSOCFI::buildCFICheck() {
 
   LLVMContext &Ctx = M->getContext();
   Constant *C = M->getOrInsertFunction(
-      "__cfi_check",
-      FunctionType::get(
-          Type::getVoidTy(Ctx),
-          {Type::getInt64Ty(Ctx), PointerType::getUnqual(Type::getInt8Ty(Ctx))},
-          false));
+      "__cfi_check", Type::getVoidTy(Ctx), Type::getInt64Ty(Ctx),
+      Type::getInt8PtrTy(Ctx), Type::getInt8PtrTy(Ctx), nullptr);
   Function *F = dyn_cast<Function>(C);
   F->setAlignment(4096);
   auto args = F->arg_begin();
-  Argument &CallSiteTypeId = *(args++);
+  Value &CallSiteTypeId = *(args++);
   CallSiteTypeId.setName("CallSiteTypeId");
-  Argument &Addr = *(args++);
+  Value &Addr = *(args++);
   Addr.setName("Addr");
+  Value &CFICheckFailData = *(args++);
+  CFICheckFailData.setName("CFICheckFailData");
   assert(args == F->arg_end());
 
   BasicBlock *BB = BasicBlock::Create(Ctx, "entry", F);
+  BasicBlock *ExitBB = BasicBlock::Create(Ctx, "exit", F);
 
-  BasicBlock *TrapBB = BasicBlock::Create(Ctx, "trap", F);
-  IRBuilder<> IRBTrap(TrapBB);
-  Function *TrapFn = Intrinsic::getDeclaration(M, Intrinsic::trap);
-  llvm::CallInst *TrapCall = IRBTrap.CreateCall(TrapFn);
-  TrapCall->setDoesNotReturn();
-  TrapCall->setDoesNotThrow();
-  IRBTrap.CreateUnreachable();
+  BasicBlock *TrapBB = BasicBlock::Create(Ctx, "fail", F);
+  IRBuilder<> IRBFail(TrapBB);
+  Constant *CFICheckFailFn = M->getOrInsertFunction(
+      "__cfi_check_fail", Type::getVoidTy(Ctx), Type::getInt8PtrTy(Ctx),
+      Type::getInt8PtrTy(Ctx), nullptr);
+  IRBFail.CreateCall(CFICheckFailFn, {&CFICheckFailData, &Addr});
+  IRBFail.CreateBr(ExitBB);
 
-  BasicBlock *ExitBB = BasicBlock::Create(Ctx, "exit", F);
   IRBuilder<> IRBExit(ExitBB);
   IRBExit.CreateRetVoid();
 

Modified: llvm/trunk/test/Transforms/CrossDSOCFI/basic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/CrossDSOCFI/basic.ll?rev=258746&r1=258745&r2=258746&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/CrossDSOCFI/basic.ll (original)
+++ llvm/trunk/test/Transforms/CrossDSOCFI/basic.ll Mon Jan 25 17:35:03 2016
@@ -1,35 +1,35 @@
 ; RUN: opt -S -cross-dso-cfi < %s | FileCheck %s
 
-; CHECK:     define void @__cfi_check(i64 %[[TYPE:.*]], i8* %[[ADDR:.*]]) align 4096
-; CHECK:     switch i64 %[[TYPE]], label %[[TRAP:.*]] [
+; CHECK:     define void @__cfi_check(i64 %[[TYPE:.*]], i8* %[[ADDR:.*]], i8* %[[DATA:.*]]) align 4096
+; CHECK:     switch i64 %[[TYPE]], label %[[FAIL:.*]] [
 ; CHECK-NEXT:   i64 111, label %[[L1:.*]]
 ; CHECK-NEXT:   i64 222, label %[[L2:.*]]
 ; CHECK-NEXT:   i64 333, label %[[L3:.*]]
 ; CHECK-NEXT:   i64 444, label %[[L4:.*]]
 ; CHECK-NEXT: {{]$}}
 
-; CHECK:     [[TRAP]]:
-; CHECK-NEXT:   call void @llvm.trap()
-; CHECK-MEXT:   unreachable
-
 ; CHECK:     [[EXIT:.*]]:
 ; CHECK-NEXT:   ret void
 
+; CHECK:     [[FAIL]]:
+; CHECK-NEXT:   call void @__cfi_check_fail(i8* %[[DATA]], i8* %[[ADDR]])
+; CHECK-NEXT:   br label %[[EXIT]]
+
 ; CHECK:     [[L1]]:
 ; CHECK-NEXT:   call i1 @llvm.bitset.test(i8* %[[ADDR]], metadata i64 111)
-; CHECK-NEXT:   br {{.*}} label %[[EXIT]], label %[[TRAP]]
+; CHECK-NEXT:   br {{.*}} label %[[EXIT]], label %[[FAIL]]
 
 ; CHECK:     [[L2]]:
 ; CHECK-NEXT:   call i1 @llvm.bitset.test(i8* %[[ADDR]], metadata i64 222)
-; CHECK-NEXT:   br {{.*}} label %[[EXIT]], label %[[TRAP]]
+; CHECK-NEXT:   br {{.*}} label %[[EXIT]], label %[[FAIL]]
 
 ; CHECK:     [[L3]]:
 ; CHECK-NEXT:   call i1 @llvm.bitset.test(i8* %[[ADDR]], metadata i64 333)
-; CHECK-NEXT:   br {{.*}} label %[[EXIT]], label %[[TRAP]]
+; CHECK-NEXT:   br {{.*}} label %[[EXIT]], label %[[FAIL]]
 
 ; CHECK:     [[L4]]:
 ; CHECK-NEXT:   call i1 @llvm.bitset.test(i8* %[[ADDR]], metadata i64 444)
-; CHECK-NEXT:   br {{.*}} label %[[EXIT]], label %[[TRAP]]
+; CHECK-NEXT:   br {{.*}} label %[[EXIT]], label %[[FAIL]]
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
@@ -66,6 +66,11 @@ entry:
   ret i32 5
 }
 
+define weak_odr hidden void @__cfi_check_fail(i8*, i8*) {
+entry:
+  ret void
+}
+
 !llvm.bitsets = !{!0, !1, !2, !3, !4, !7, !8, !9, !10, !11, !12, !13, !14, !15}
 !llvm.module.flags = !{!17}