junbuml edited subscribers, added: cfe-commits; removed: llvm-commits.
junbuml updated this revision to Diff 36107.
http://reviews.llvm.org/D12979
Files:
lib/CodeGen/CGCall.cpp
lib/CodeGen/CGException.cpp
lib/CodeGen/CodeGenFunction.cpp
lib/CodeGen/CodeGenFunction.h
test/CodeGenCXX/throw-expressions.cpp
Index: test/CodeGenCXX/throw-expressions.cpp
===================================================================
--- test/CodeGenCXX/throw-expressions.cpp
+++ test/CodeGenCXX/throw-expressions.cpp
@@ -112,3 +112,14 @@
// CHECK: ret i32* @val
return cond ? val : ((throw "foo"));
}
+
+// CHECK-LABEL: _Z5test9v
+// CHECK: invoke void @_ZN2EHC1Ev(%class.EH* %0) [[ATTR_NUM:#[0-9]+]]
+// CHECK: attributes [[ATTR_NUM]] = { cold noinline }
+class EH {
+public :
+ EH();
+};
+void test9() {
+ throw EH();
+}
Index: lib/CodeGen/CodeGenFunction.h
===================================================================
--- lib/CodeGen/CodeGenFunction.h
+++ lib/CodeGen/CodeGenFunction.h
@@ -283,6 +283,11 @@
/// finally block or filter expression.
bool IsOutlinedSEHHelper;
+ // True if the current insertion point is in cold regions (e.g., exception
+ // handling regions). As of now, this flag is ture only when handling throw
+ // statement.
+ bool IsColdRegion;
+
const CodeGen::CGBlockInfo *BlockInfo;
llvm::Value *BlockPointer;
Index: lib/CodeGen/CodeGenFunction.cpp
===================================================================
--- lib/CodeGen/CodeGenFunction.cpp
+++ lib/CodeGen/CodeGenFunction.cpp
@@ -44,7 +44,7 @@
CapturedStmtInfo(nullptr),
SanOpts(CGM.getLangOpts().Sanitize), IsSanitizerScope(false),
CurFuncIsThunk(false), AutoreleaseResult(false), SawAsmBlock(false),
- IsOutlinedSEHHelper(false),
+ IsOutlinedSEHHelper(false), IsColdRegion(false),
BlockInfo(nullptr), BlockPointer(nullptr),
LambdaThisCaptureField(nullptr), NormalCleanupDest(nullptr),
NextCleanupDestIndex(1), FirstBlockInfo(nullptr), EHResumeBlock(nullptr),
Index: lib/CodeGen/CGException.cpp
===================================================================
--- lib/CodeGen/CGException.cpp
+++ lib/CodeGen/CGException.cpp
@@ -400,6 +400,11 @@
void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E,
bool KeepInsertionPoint) {
+ // While handling the throw statement, inform that the insertion point is in
+ // cold regions so that we could perform cold region specific IR generation.
+ // For example, the NoInline attribute could be added in CallSites in throw
+ // statements.
+ IsColdRegion = true;
if (const Expr *SubExpr = E->getSubExpr()) {
QualType ThrowType = SubExpr->getType();
if (ThrowType->isObjCObjectPointerType()) {
@@ -417,6 +422,9 @@
// to leave ourselves at a valid insertion point.
if (KeepInsertionPoint)
EmitBlock(createBasicBlock("throw.cont"));
+
+ IsColdRegion = false;
+ // FIXME: Similarly, we could set IsColdRegion for catch blocks in ExitCXXTryStmt().
}
void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -3464,6 +3464,27 @@
Attrs.addAttribute(getLLVMContext(), llvm::AttributeSet::FunctionIndex,
llvm::Attribute::NoInline);
+ // As of now, IsColdRegion is true only while handling throw statements.
+ // It might be reasonable to avoid inlining CallSites invoked in exception
+ // handling context so that we can reduce code size blow-up in EH regions
+ // as well as indirectly increase inline opportunities for unwinding
+ // functions containing exception handling code.
+ if (IsColdRegion) {
+ // FIXME: We add both NoInline and Cold because the inline cold-threshold
+ // is not tuned yet (r200898). As of now, considering that CallSites in
+ // exception handling regions are very cold is not unreasonable even without
+ // profiling, and avoiding inlining in exception handling region may not have
+ // significant impacts on performance unless a program execution logic
+ // really depends on exception handling flows. However, when the inline
+ // cold-threshold is tuned, we may need to remove NoInline here so that we
+ // can allow a trivial constructor to be inlined.
+ Attrs =
+ Attrs.addAttribute(getLLVMContext(), llvm::AttributeSet::FunctionIndex,
+ llvm::Attribute::NoInline);
+ Attrs =
+ Attrs.addAttribute(getLLVMContext(), llvm::AttributeSet::FunctionIndex,
+ llvm::Attribute::Cold);
+ }
CS.setAttributes(Attrs);
CS.setCallingConv(static_cast<llvm::CallingConv::ID>(CallingConv));
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