ahatanak created this revision.
This patch fixes an infinite loop in IRGen that occurs when compiling the
following code:
void FUNC2() {
static void (^const block1)(int) = ^(int a){
if (a--)
block1(a);
};
When IRGen visits the call to "block1", it knows that it always calls the
block defined in Func2 enclosing the call (because "block1" is const
qualified), so it tries to emit the reference to "block1" as a constant and
calls CodeGenModule::GetAddrOfGlobalBlock to get the address of the block.
CodeGenModule::GetAddrOfGlobalBlock checks whether the block has already been
emitted (calling getAddrOfGlobalBlockIfEmitted). If the block hasn't been
emitted, it starts generating the block invoke function, which causes the
infinite loop.
I believe this happens because clang's constant folding got smarter (see
commit log of r290661, for example) and the call "refExpr->EvaluateAsRValue" in
CodeGenFunction::tryEmitAsConstant returns true now as a result.
This patch prevents the infinite loop by building the global block in
GenerateBlockFunction before it emits the IR of the body of the function.
rdar://problem/34541684
https://reviews.llvm.org/D38118
Files:
lib/CodeGen/CGBlocks.cpp
lib/CodeGen/CodeGenFunction.h
test/CodeGen/mangle-blocks.c
test/CodeGenObjC/local-static-block.m
test/CodeGenObjC/mangle-blocks.m
Index: test/CodeGenObjC/mangle-blocks.m
===================================================================
--- test/CodeGenObjC/mangle-blocks.m
+++ test/CodeGenObjC/mangle-blocks.m
@@ -18,11 +18,11 @@
@end
// CHECK: @"__func__.__14-[Test mangle]_block_invoke_2" = private unnamed_addr constant [30 x i8] c"-[Test mangle]_block_invoke_2\00", align 1
-// CHECK: @.str = private unnamed_addr constant {{.*}}, align 1
-// CHECK: @.str.1 = private unnamed_addr constant [7 x i8] c"mangle\00", align 1
+// CHECK: @.str{{.*}} = private unnamed_addr constant {{.*}}, align 1
+// CHECK: @.str[[STR1:.*]] = private unnamed_addr constant [7 x i8] c"mangle\00", align 1
// CHECK: define internal void @"__14-[Test mangle]_block_invoke"(i8* %.block_descriptor)
// CHECK: define internal void @"__14-[Test mangle]_block_invoke_2"(i8* %.block_descriptor){{.*}}{
-// CHECK: call void @__assert_rtn(i8* getelementptr inbounds ([30 x i8], [30 x i8]* @"__func__.__14-[Test mangle]_block_invoke_2", i32 0, i32 0), i8* getelementptr inbounds {{.*}}, i32 14, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.1, i32 0, i32 0))
+// CHECK: call void @__assert_rtn(i8* getelementptr inbounds ([30 x i8], [30 x i8]* @"__func__.__14-[Test mangle]_block_invoke_2", i32 0, i32 0), i8* getelementptr inbounds {{.*}}, i32 14, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str[[STR1]], i32 0, i32 0))
// CHECK: }
Index: test/CodeGenObjC/local-static-block.m
===================================================================
--- test/CodeGenObjC/local-static-block.m
+++ test/CodeGenObjC/local-static-block.m
@@ -46,6 +46,17 @@
}
}
+void FUNC2() {
+ static void (^const block1)(int) = ^(int a){
+ if (a--)
+ block1(a);
+ };
+}
+
+// CHECK-LABEL-LP64: define void @FUNC2(
+// CHECK: define internal void @_block_invoke{{.*}}(
+// CHECK: call void %{{.*}}(i8* bitcast ({ i8**, i32, i32, i8*, %struct.__block_descriptor* }* @__block_literal_global{{.*}} to i8*), i32 %{{.*}})
+
void FUNC1()
{
static NSArray *(^ArrayRecurs)(NSArray *addresses, unsigned long level) = ^(NSArray *addresses, unsigned long level) {
Index: test/CodeGen/mangle-blocks.c
===================================================================
--- test/CodeGen/mangle-blocks.c
+++ test/CodeGen/mangle-blocks.c
@@ -12,12 +12,12 @@
}
// CHECK: @__func__.__mangle_block_invoke_2 = private unnamed_addr constant [22 x i8] c"mangle_block_invoke_2\00", align 1
-// CHECK: @.str = private unnamed_addr constant {{.*}}, align 1
-// CHECK: @.str.1 = private unnamed_addr constant [7 x i8] c"mangle\00", align 1
+// CHECK: @.str{{.*}} = private unnamed_addr constant {{.*}}, align 1
+// CHECK: @.str[[STR1:.*]] = private unnamed_addr constant [7 x i8] c"mangle\00", align 1
// CHECK: define internal void @__mangle_block_invoke(i8* %.block_descriptor)
// CHECK: define internal void @__mangle_block_invoke_2(i8* %.block_descriptor){{.*}}{
-// CHECK: call void @__assert_rtn(i8* getelementptr inbounds ([22 x i8], [22 x i8]* @__func__.__mangle_block_invoke_2, i32 0, i32 0), i8* getelementptr inbounds {{.*}}, i32 9, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.1, i32 0, i32 0))
+// CHECK: call void @__assert_rtn(i8* getelementptr inbounds ([22 x i8], [22 x i8]* @__func__.__mangle_block_invoke_2, i32 0, i32 0), i8* getelementptr inbounds {{.*}}, i32 9, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str[[STR1]], i32 0, i32 0))
// CHECK: }
Index: lib/CodeGen/CodeGenFunction.h
===================================================================
--- lib/CodeGen/CodeGenFunction.h
+++ lib/CodeGen/CodeGenFunction.h
@@ -1586,7 +1586,8 @@
llvm::Function *GenerateBlockFunction(GlobalDecl GD,
const CGBlockInfo &Info,
const DeclMapTy &ldm,
- bool IsLambdaConversionToBlock);
+ bool IsLambdaConversionToBlock,
+ bool BuildGlobalBlock);
llvm::Constant *GenerateCopyHelperFunction(const CGBlockInfo &blockInfo);
llvm::Constant *GenerateDestroyHelperFunction(const CGBlockInfo &blockInfo);
Index: lib/CodeGen/CGBlocks.cpp
===================================================================
--- lib/CodeGen/CGBlocks.cpp
+++ lib/CodeGen/CGBlocks.cpp
@@ -725,12 +725,13 @@
llvm::Constant *blockFn
= CodeGenFunction(CGM, true).GenerateBlockFunction(CurGD, blockInfo,
LocalDeclMap,
- isLambdaConv);
+ isLambdaConv,
+ blockInfo.CanBeGlobal);
blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy);
// If there is nothing to capture, we can emit this as a global block.
if (blockInfo.CanBeGlobal)
- return buildGlobalBlock(CGM, blockInfo, blockFn);
+ return CGM.getAddrOfGlobalBlockIfEmitted(blockInfo.BlockExpression);
// Otherwise, we have to emit this as a local block.
@@ -1120,11 +1121,10 @@
blockFn = CodeGenFunction(*this).GenerateBlockFunction(GlobalDecl(),
blockInfo,
LocalDeclMap,
- false);
+ false, true);
}
- blockFn = llvm::ConstantExpr::getBitCast(blockFn, VoidPtrTy);
- return buildGlobalBlock(*this, blockInfo, blockFn);
+ return getAddrOfGlobalBlockIfEmitted(BE);
}
static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
@@ -1226,7 +1226,8 @@
CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
const CGBlockInfo &blockInfo,
const DeclMapTy &ldm,
- bool IsLambdaConversionToBlock) {
+ bool IsLambdaConversionToBlock,
+ bool BuildGlobalBlock) {
const BlockDecl *blockDecl = blockInfo.getBlockDecl();
CurGD = GD;
@@ -1285,6 +1286,10 @@
fnLLVMType, llvm::GlobalValue::InternalLinkage, name, &CGM.getModule());
CGM.SetInternalFunctionAttributes(blockDecl, fn, fnInfo);
+ if (BuildGlobalBlock)
+ buildGlobalBlock(CGM, blockInfo,
+ llvm::ConstantExpr::getBitCast(fn, VoidPtrTy));
+
// Begin generating the function.
StartFunction(blockDecl, fnType->getReturnType(), fn, fnInfo, args,
blockDecl->getLocation(),
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