[MS] Implement the __fastfail intrinsic as a builtin

__fastfail terminates the process immediately with a special system
call. It does not run any process shutdown code or exception recovery
logic.

Fixes PR31854

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@294606 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/Builtins.def b/include/clang/Basic/Builtins.def
index 326a8fa66360732ac26373ee63c528c41a26054c..08234c0051afc97ef33341e295251e2cc0eb0f18 100644 (file)
--- a/include/clang/Basic/Builtins.def
+++ b/include/clang/Basic/Builtins.def
@@ -773,6 +773,7 @@ LANGBUILTIN(_rotr,   "UiUii",     "n", ALL_MS_LANGUAGES)
 LANGBUILTIN(_lrotr,  "ULiULii",   "n", ALL_MS_LANGUAGES)
 LANGBUILTIN(_rotr64, "ULLiULLii", "n", ALL_MS_LANGUAGES)
 LANGBUILTIN(__va_start,       "vc**.", "nt", ALL_MS_LANGUAGES)
+LANGBUILTIN(__fastfail, "vUi",    "nr", ALL_MS_LANGUAGES)
 
 // Microsoft library builtins.
 LIBBUILTIN(_setjmpex, "iJ", "fj",   "setjmpex.h", ALL_MS_LANGUAGES)

diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index 9ecf118ed9eccc325b598bd1f1b926239fdaf6cf..5bdb5ee8d15fa373be6ac7087aebca9569b240a4 100644 (file)
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -482,10 +482,11 @@ enum class CodeGenFunction::MSVCIntrin {
   _InterlockedIncrement,
   _InterlockedOr,
   _InterlockedXor,
+  __fastfail,
 };
 
 Value *CodeGenFunction::EmitMSVCBuiltinExpr(MSVCIntrin BuiltinID,
-  const CallExpr *E) {
+                                            const CallExpr *E) {
   switch (BuiltinID) {
   case MSVCIntrin::_BitScanForward:
   case MSVCIntrin::_BitScanReverse: {
@@ -566,6 +567,37 @@ Value *CodeGenFunction::EmitMSVCBuiltinExpr(MSVCIntrin BuiltinID,
       llvm::AtomicOrdering::SequentiallyConsistent);
     return Builder.CreateAdd(RMWI, ConstantInt::get(IntTy, 1));
   }
+
+  case MSVCIntrin::__fastfail: {
+    // Request immediate process termination from the kernel. The instruction
+    // sequences to do this are documented on MSDN:
+    // https://msdn.microsoft.com/en-us/library/dn774154.aspx
+    llvm::Triple::ArchType ISA = getTarget().getTriple().getArch();
+    StringRef Asm, Constraints;
+    switch (ISA) {
+    default:
+      ErrorUnsupported(E, "__fastfail call for this architecture");
+      break;
+    case llvm::Triple::x86:
+    case llvm::Triple::x86_64:
+      Asm = "int $$0x29";
+      Constraints = "{cx}";
+      break;
+    case llvm::Triple::thumb:
+      Asm = "udf #251";
+      Constraints = "{r0}";
+      break;
+    }
+    llvm::FunctionType *FTy = llvm::FunctionType::get(VoidTy, {Int32Ty}, false);
+    llvm::InlineAsm *IA =
+        llvm::InlineAsm::get(FTy, Asm, Constraints, /*SideEffects=*/true);
+    llvm::AttributeSet NoReturnAttr =
+        AttributeSet::get(getLLVMContext(), llvm::AttributeSet::FunctionIndex,
+                          llvm::Attribute::NoReturn);
+    CallSite CS = Builder.CreateCall(IA, EmitScalarExpr(E->getArg(0)));
+    CS.setAttributes(NoReturnAttr);
+    return CS.getInstruction();
+  }
   }
   llvm_unreachable("Incorrect MSVC intrinsic!");
 }
@@ -2276,6 +2308,11 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
     break;
   }
 
+  case Builtin::BI__fastfail: {
+    return RValue::get(EmitMSVCBuiltinExpr(MSVCIntrin::__fastfail, E));
+    break;
+  }
+
   case Builtin::BI__builtin_coro_size: {
     auto & Context = getContext();
     auto SizeTy = Context.getSizeType();

diff --git a/lib/Headers/intrin.h b/lib/Headers/intrin.h
index a35262af846ab5dfc395e4979d97bb6c7197d25e..1b98dd8267ee0dcd13884ac93155f0fec481b92e 100644 (file)
--- a/lib/Headers/intrin.h
+++ b/lib/Headers/intrin.h
@@ -69,7 +69,6 @@ static __inline__
 __int64 __emul(int, int);
 static __inline__
 unsigned __int64 __emulu(unsigned int, unsigned int);
-void __cdecl __fastfail(unsigned int);
 unsigned int __getcallerseflags(void);
 static __inline__
 void __halt(void);

diff --git a/test/CodeGen/ms-intrinsics.c b/test/CodeGen/ms-intrinsics.c
index 25eae44e02720573a235f3368a11ae265415ef94..7b03035615eeaa524be21abd50e687260bfdce61 100644 (file)
--- a/test/CodeGen/ms-intrinsics.c
+++ b/test/CodeGen/ms-intrinsics.c
@@ -3,7 +3,7 @@
 // RUN:         | FileCheck %s -check-prefixes CHECK,CHECK-I386,CHECK-INTEL
 // RUN: %clang_cc1 -ffreestanding -fms-extensions -fms-compatibility -fms-compatibility-version=17.00 \
 // RUN:         -triple thumbv7--windows -Oz -emit-llvm %s -o - \
-// RUN:         | FileCheck %s --check-prefixes CHECK,CHECK-ARM-X64
+// RUN:         | FileCheck %s --check-prefixes CHECK,CHECK-ARM,CHECK-ARM-X64
 // RUN: %clang_cc1 -ffreestanding -fms-extensions -fms-compatibility -fms-compatibility-version=17.00 \
 // RUN:         -triple x86_64--windows -Oz -emit-llvm %s -o - \
 // RUN:         | FileCheck %s --check-prefixes CHECK,CHECK-X64,CHECK-ARM-X64,CHECK-INTEL
@@ -419,3 +419,15 @@ __int64 test_InterlockedDecrement64(__int64 volatile *Addend) {
 // CHECK-ARM-X64: }
 
 #endif
+
+void test__fastfail() {
+  __fastfail(42);
+}
+// CHECK-LABEL: define{{.*}} void @test__fastfail()
+// CHECK-ARM: call void asm sideeffect "udf #251", "{r0}"(i32 42) #[[NORETURN:[0-9]+]]
+// CHECK-INTEL: call void asm sideeffect "int $$0x29", "{cx}"(i32 42) #[[NORETURN:[0-9]+]]
+
+// Attributes come last.
+
+// CHECK: attributes #[[NORETURN]] = { noreturn{{.*}} }
+