[clang] [clang][bytecode] Save Immediate bit in Function (PR #139671)

[Timm Baeder via cfe-commits]

Timm =?utf-8?q?Bäder?= <tbaeder at redhat.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/139671 at github.com>


https://github.com/tbaederr updated https://github.com/llvm/llvm-project/pull/139671

>From dbfd167600797aea5dcc34fc2f6d9e6659363bda Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Mon, 12 May 2025 17:59:38 +0200
Subject: [PATCH 1/2] [clang][bytecode] Save Immediate bit in Function

Otherwise, we have to look at the FunctionDecl at every function call.
---
 clang/lib/AST/ByteCode/Function.cpp | 1 +
 clang/lib/AST/ByteCode/Function.h   | 2 ++
 clang/lib/AST/ByteCode/Interp.cpp   | 2 +-
 3 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/clang/lib/AST/ByteCode/Function.cpp b/clang/lib/AST/ByteCode/Function.cpp
index 8a4e089d9ecd0..f790d13738953 100644
--- a/clang/lib/AST/ByteCode/Function.cpp
+++ b/clang/lib/AST/ByteCode/Function.cpp
@@ -26,6 +26,7 @@ Function::Function(Program &P, FunctionDeclTy Source, unsigned ArgSize,
       HasRVO(HasRVO) {
   if (const auto *F = dyn_cast<const FunctionDecl *>(Source)) {
     Variadic = F->isVariadic();
+    Immediate = F->isImmediateFunction();
     if (const auto *CD = dyn_cast<CXXConstructorDecl>(F)) {
       Virtual = CD->isVirtual();
       Kind = FunctionKind::Ctor;
diff --git a/clang/lib/AST/ByteCode/Function.h b/clang/lib/AST/ByteCode/Function.h
index 436574dd3a4c7..c21ac441ad5d5 100644
--- a/clang/lib/AST/ByteCode/Function.h
+++ b/clang/lib/AST/ByteCode/Function.h
@@ -155,6 +155,7 @@ class Function final {
 
   /// Checks if the function is virtual.
   bool isVirtual() const { return Virtual; };
+  bool isImmediate() const { return Immediate; }
 
   /// Checks if the function is a constructor.
   bool isConstructor() const { return Kind == FunctionKind::Ctor; }
@@ -292,6 +293,7 @@ class Function final {
   bool Defined = false;
   bool Variadic = false;
   bool Virtual = false;
+  bool Immediate = false;
 
 public:
   /// Dumps the disassembled bytecode to \c llvm::errs().
diff --git a/clang/lib/AST/ByteCode/Interp.cpp b/clang/lib/AST/ByteCode/Interp.cpp
index 43f8d156589b6..a13b56c82cb44 100644
--- a/clang/lib/AST/ByteCode/Interp.cpp
+++ b/clang/lib/AST/ByteCode/Interp.cpp
@@ -1502,7 +1502,7 @@ bool Call(InterpState &S, CodePtr OpPC, const Function *Func,
   InterpFrame *FrameBefore = S.Current;
   S.Current = NewFrame.get();
 
-  InterpStateCCOverride CCOverride(S, Func->getDecl()->isImmediateFunction());
+  InterpStateCCOverride CCOverride(S, Func->isImmediate());
   // Note that we cannot assert(CallResult.hasValue()) here since
   // Ret() above only sets the APValue if the curent frame doesn't
   // have a caller set.

>From 0d3bbfaa33e78d825f41f32f272fa75c7143bea3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Tue, 13 May 2025 09:08:13 +0200
Subject: [PATCH 2/2] Use bitfields

Actually shrinks the struct from 528 to 520 bytes.
---
 clang/lib/AST/ByteCode/Function.h | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/clang/lib/AST/ByteCode/Function.h b/clang/lib/AST/ByteCode/Function.h
index c21ac441ad5d5..45a1c1bf9f839 100644
--- a/clang/lib/AST/ByteCode/Function.h
+++ b/clang/lib/AST/ByteCode/Function.h
@@ -277,23 +277,32 @@ class Function final {
   /// List of parameter offsets.
   llvm::SmallVector<unsigned, 8> ParamOffsets;
   /// Flag to indicate if the function is valid.
-  bool IsValid = false;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned IsValid : 1;
   /// Flag to indicate if the function is done being
   /// compiled to bytecode.
-  bool IsFullyCompiled = false;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned IsFullyCompiled : 1;
   /// Flag indicating if this function takes the this pointer
   /// as the first implicit argument
-  bool HasThisPointer = false;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned HasThisPointer : 1;
   /// Whether this function has Return Value Optimization, i.e.
   /// the return value is constructed in the caller's stack frame.
   /// This is done for functions that return non-primive values.
-  bool HasRVO = false;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned HasRVO : 1;
   /// If we've already compiled the function's body.
-  bool HasBody = false;
-  bool Defined = false;
-  bool Variadic = false;
-  bool Virtual = false;
-  bool Immediate = false;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned HasBody : 1;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned Defined : 1;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned Variadic : 1;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned Virtual : 1;
+  LLVM_PREFERRED_TYPE(bool)
+  unsigned Immediate : 1;
 
 public:
   /// Dumps the disassembled bytecode to \c llvm::errs().