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[clang][bytecode] Initialize global strings via memcpy (#140789)

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If we know the char width is 1, we can just copy
the data over instead of going through the Pointer API.
This commit is contained in:
Timm Baeder
2025-05-21 07:56:15 +02:00
committed by GitHub
parent 3c8a6bc3b7
commit 645846d43b
1 changed files with 29 additions and 23 deletions
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52
clang/lib/AST/ByteCode/Program.cpp
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@@ -68,32 +68,38 @@ unsigned Program::createGlobalString(const StringLiteral *S, const Expr *Base) {
/*isExtern=*/false);
G->block()->invokeCtor();
new (G->block()->rawData()) InlineDescriptor(Desc);
new (G->block()->rawData())
GlobalInlineDescriptor{GlobalInitState::Initialized};
Globals.push_back(G);
// Construct the string in storage.
const Pointer Ptr(G->block());
for (unsigned I = 0; I <= StringLength; ++I) {
Pointer Field = Ptr.atIndex(I);
const uint32_t CodePoint = I == StringLength ? 0 : S->getCodeUnit(I);
switch (CharType) {
case PT_Sint8: {
using T = PrimConv<PT_Sint8>::T;
Field.deref<T>() = T::from(CodePoint, BitWidth);
break;
}
case PT_Uint16: {
using T = PrimConv<PT_Uint16>::T;
Field.deref<T>() = T::from(CodePoint, BitWidth);
break;
}
case PT_Uint32: {
using T = PrimConv<PT_Uint32>::T;
Field.deref<T>() = T::from(CodePoint, BitWidth);
break;
}
default:
llvm_unreachable("unsupported character type");
if (CharWidth == 1) {
std::memcpy(&Ptr.atIndex(0).deref<char>(), S->getString().data(),
StringLength);
} else {
// Construct the string in storage.
for (unsigned I = 0; I <= StringLength; ++I) {
Pointer Field = Ptr.atIndex(I);
const uint32_t CodePoint = I == StringLength ? 0 : S->getCodeUnit(I);
switch (CharType) {
case PT_Sint8: {
using T = PrimConv<PT_Sint8>::T;
Field.deref<T>() = T::from(CodePoint, BitWidth);
break;
}
case PT_Uint16: {
using T = PrimConv<PT_Uint16>::T;
Field.deref<T>() = T::from(CodePoint, BitWidth);
break;
}
case PT_Uint32: {
using T = PrimConv<PT_Uint32>::T;
Field.deref<T>() = T::from(CodePoint, BitWidth);
break;
}
default:
llvm_unreachable("unsupported character type");
}
}
}
Ptr.initialize();