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Compute and cache the value representation of a type when it becomes complete. #3271

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merged 16 commits into from
Oct 13, 2023
Merged

Compute and cache the value representation of a type when it becomes complete. #3271

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27df53f
Fix lowering of tuple values to use the value representation rather than
zygoloid Oct 6, 2023
4e9162b
Park
zygoloid Oct 11, 2023
d26138b
Merge branch 'trunk' into toolchain-tuple-value-type
zygoloid Oct 11, 2023
49de992
Compute a value representation type and store it on the SemIR::File.
zygoloid Oct 12, 2023
0d13567
Merge branch 'trunk' into toolchain-tuple-value-type
zygoloid Oct 12, 2023
e4a9bdf
Make treatment of builtins consistent. Autoupdate.
zygoloid Oct 12, 2023
89088fc
Bug fixes.
zygoloid Oct 12, 2023
b54ee10
Fix YAML test.
zygoloid Oct 12, 2023
9a4089a
Merge branch 'trunk' into toolchain-tuple-value-type
zygoloid Oct 12, 2023
13f34a1
Autoupdate
zygoloid Oct 12, 2023
b9e100c
Add TODO comments.
zygoloid Oct 13, 2023
efb54b4
Add a test TODO.
zygoloid Oct 13, 2023
58e9196
Merge branch 'trunk' into toolchain-tuple-value-type
zygoloid Oct 13, 2023
f05a01b
Post-merge fixes.
zygoloid Oct 13, 2023
67916c6
Merge branch 'trunk' into toolchain-tuple-value-type
zygoloid Oct 13, 2023
a2fcf03
Merge branch 'trunk' into toolchain-tuple-value-type
zygoloid Oct 13, 2023
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55 changes: 29 additions & 26 deletions toolchain/lower/handle.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -306,21 +306,11 @@ static auto GetStructOrTupleElement(FunctionContext& context,
auto* elem_ptr =
context.builder().CreateStructGEP(aggr_type, aggr_value, idx, name);

// If this is a value access, load the element if necessary.
// If this is a value access, we were holding a pointer to the value, so load
// the element.
if (aggr_cat == SemIR::ExpressionCategory::Value) {
switch (
SemIR::GetValueRepresentation(context.semantics_ir(), result_type_id)
.kind) {
case SemIR::ValueRepresentation::None:
return llvm::PoisonValue::get(context.GetType(result_type_id));
case SemIR::ValueRepresentation::Copy:
return context.builder().CreateLoad(context.GetType(result_type_id),
elem_ptr, name + ".load");
case SemIR::ValueRepresentation::Pointer:
return elem_ptr;
case SemIR::ValueRepresentation::Custom:
CARBON_FATAL() << "TODO: Add support for custom value representation";
}
return context.builder().CreateLoad(context.GetType(result_type_id),
elem_ptr, name + ".load");
}
return elem_ptr;
}
Expand Down Expand Up @@ -360,12 +350,10 @@ auto EmitStructOrTupleValueRepresentation(FunctionContext& context,
SemIR::TypeId type_id,
SemIR::NodeBlockId refs_id,
llvm::Twine name) -> llvm::Value* {
auto* llvm_type = context.GetType(type_id);

switch (SemIR::GetValueRepresentation(context.semantics_ir(), type_id).kind) {
case SemIR::ValueRepresentation::None:
// TODO: Add a helper to get a "no value representation" value.
return llvm::PoisonValue::get(llvm_type);
return llvm::PoisonValue::get(context.GetType(type_id));

case SemIR::ValueRepresentation::Copy: {
auto refs = context.semantics_ir().GetNodeBlock(refs_id);
Expand All @@ -374,20 +362,35 @@ auto EmitStructOrTupleValueRepresentation(FunctionContext& context,
// TODO: Remove the LLVM StructType wrapper in this case, so we don't
// need this `insert_value` wrapping.
return context.builder().CreateInsertValue(
llvm::PoisonValue::get(llvm_type), context.GetLocal(refs[0]), {0});
llvm::PoisonValue::get(context.GetType(type_id)),
context.GetLocal(refs[0]), {0});
}

case SemIR::ValueRepresentation::Pointer: {
// Write the object representation to a local alloca so we can produce a
// pointer to it as the value representation.
auto* alloca = context.builder().CreateAlloca(
llvm_type, /*ArraySize=*/nullptr, name);
auto refs = context.semantics_ir().GetNodeBlock(refs_id);

// Compute the type of the value representation. Note that we don't use
// `context.GetType(type_id)` here, because that would give us the object
// representation rather than the value representation.
// TODO: Consider precomputing or caching this.
llvm::SmallVector<llvm::Type*> element_types;
element_types.reserve(refs.size());
for (auto [i, ref] : llvm::enumerate(refs)) {
element_types.push_back(context.GetLocal(ref)->getType());
}
llvm::Type* llvm_value_rep_type =
llvm::StructType::get(context.llvm_context(), element_types);

// Write the value representation to a local alloca so we can produce a
// pointer to it as the value representation of the struct or tuple.
auto* alloca =
context.builder().CreateAlloca(llvm_value_rep_type,
/*ArraySize=*/nullptr, name);
for (auto [i, ref] :
llvm::enumerate(context.semantics_ir().GetNodeBlock(refs_id))) {
auto* gep = context.builder().CreateStructGEP(llvm_type, alloca, i);
// TODO: We are loading a value representation here and storing an
// object representation!
context.builder().CreateStore(context.GetLocal(ref), gep);
context.builder().CreateStore(
context.GetLocal(ref),
context.builder().CreateStructGEP(llvm_value_rep_type, alloca, i));
}
return alloca;
}
Expand Down
13 changes: 7 additions & 6 deletions toolchain/lower/testdata/let/tuple.carbon
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Original file line number Diff line number Diff line change
Expand Up @@ -49,13 +49,14 @@ fn F() -> i32 {
// CHECK:STDOUT: store i32 %7, ptr %9, align 4
// CHECK:STDOUT: %10 = getelementptr inbounds { i32, i32 }, ptr %tuple10, i32 0, i32 1
// CHECK:STDOUT: store i32 %8, ptr %10, align 4
// CHECK:STDOUT: %tuple11 = alloca { { i32, i32, i32 }, { i32, i32 } }, align 8
// CHECK:STDOUT: %11 = getelementptr inbounds { { i32, i32, i32 }, { i32, i32 } }, ptr %tuple11, i32 0, i32 0
// CHECK:STDOUT: %tuple11 = alloca { ptr, ptr }, align 8
// CHECK:STDOUT: %11 = getelementptr inbounds { ptr, ptr }, ptr %tuple11, i32 0, i32 0
// CHECK:STDOUT: store ptr %tuple, ptr %11, align 8
// CHECK:STDOUT: %12 = getelementptr inbounds { { i32, i32, i32 }, { i32, i32 } }, ptr %tuple11, i32 0, i32 1
// CHECK:STDOUT: %12 = getelementptr inbounds { ptr, ptr }, ptr %tuple11, i32 0, i32 1
// CHECK:STDOUT: store ptr %tuple10, ptr %12, align 8
// CHECK:STDOUT: %tuple.index = getelementptr inbounds { { i32, i32, i32 }, { i32, i32 } }, ptr %tuple11, i32 0, i32 1
// CHECK:STDOUT: %tuple.index12 = getelementptr inbounds { i32, i32 }, ptr %tuple.index, i32 0, i32 1
// CHECK:STDOUT: %tuple.index.load = load i32, ptr %tuple.index12, align 4
// CHECK:STDOUT: ret i32 %tuple.index.load
// CHECK:STDOUT: %tuple.index.load = load { i32, i32 }, ptr %tuple.index, align 4
// CHECK:STDOUT: %tuple.index12 = getelementptr inbounds { i32, i32 }, { i32, i32 } %tuple.index.load, i32 0, i32 1
// CHECK:STDOUT: %tuple.index.load13 = load i32, { i32, i32 } %tuple.index12, align 4
// CHECK:STDOUT: ret i32 %tuple.index.load13
// CHECK:STDOUT: }
6 changes: 3 additions & 3 deletions toolchain/lower/testdata/tuple/value_formation.carbon
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Original file line number Diff line number Diff line change
Expand Up @@ -46,10 +46,10 @@ fn F() {
// CHECK:STDOUT: store i32 %8, ptr %11, align 4
// CHECK:STDOUT: %12 = getelementptr inbounds { i32, i32, i32 }, ptr %tuple6, i32 0, i32 2
// CHECK:STDOUT: store i32 %9, ptr %12, align 4
// CHECK:STDOUT: %tuple7 = alloca { { i32, i32, i32 }, { i32, i32, i32 } }, align 8
// CHECK:STDOUT: %13 = getelementptr inbounds { { i32, i32, i32 }, { i32, i32, i32 } }, ptr %tuple7, i32 0, i32 0
// CHECK:STDOUT: %tuple7 = alloca { ptr, ptr }, align 8
// CHECK:STDOUT: %13 = getelementptr inbounds { ptr, ptr }, ptr %tuple7, i32 0, i32 0
// CHECK:STDOUT: store ptr %tuple, ptr %13, align 8
// CHECK:STDOUT: %14 = getelementptr inbounds { { i32, i32, i32 }, { i32, i32, i32 } }, ptr %tuple7, i32 0, i32 1
// CHECK:STDOUT: %14 = getelementptr inbounds { ptr, ptr }, ptr %tuple7, i32 0, i32 1
// CHECK:STDOUT: store ptr %tuple6, ptr %14, align 8
// CHECK:STDOUT: call void @G(ptr %tuple7)
// CHECK:STDOUT: ret void
Expand Down
6 changes: 3 additions & 3 deletions toolchain/lower/testdata/tuple/value_forwarding.carbon
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Expand Up @@ -16,10 +16,10 @@ fn F(a: (i32, i32, i32), b: (i32, i32, i32)) {
// CHECK:STDOUT: declare void @G(ptr)
// CHECK:STDOUT:
// CHECK:STDOUT: define void @F(ptr %a, ptr %b) {
// CHECK:STDOUT: %tuple = alloca { { i32, i32, i32 }, { i32, i32, i32 } }, align 8
// CHECK:STDOUT: %1 = getelementptr inbounds { { i32, i32, i32 }, { i32, i32, i32 } }, ptr %tuple, i32 0, i32 0
// CHECK:STDOUT: %tuple = alloca { ptr, ptr }, align 8
// CHECK:STDOUT: %1 = getelementptr inbounds { ptr, ptr }, ptr %tuple, i32 0, i32 0
// CHECK:STDOUT: store ptr %a, ptr %1, align 8
// CHECK:STDOUT: %2 = getelementptr inbounds { { i32, i32, i32 }, { i32, i32, i32 } }, ptr %tuple, i32 0, i32 1
// CHECK:STDOUT: %2 = getelementptr inbounds { ptr, ptr }, ptr %tuple, i32 0, i32 1
// CHECK:STDOUT: store ptr %b, ptr %2, align 8
// CHECK:STDOUT: call void @G(ptr %tuple)
// CHECK:STDOUT: ret void
Expand Down