carbon-language/carbon-lang
1
0
Fork 0
mirror of https://github.com/carbon-language/carbon-lang.git synced 2026-10-05 16:31:04 +01:00
Code Issues Packages Projects Releases 10 Wiki Activity

Switch CARBON_CHECK to a format string API (#4285)

Browse Source 
This switches `DCHECK` and `FATAL` as well.

The goal is to reduce the code size impact of these assertions so that
we can keep more of them enabled. Currently, the largest cost I see from
`CHECK` is not the actual check or the cold code itself, but actually
the failure to inline trivial functions due to the presence of the cold
code. This means that our goal isn't to reduce apparent code size in the
final binary but the LLVM IR cost assessed for these routines in the
inliner, which closely correlates with code size but is a bit different.

As discussed in #4283, experimentation shows that a single function call
with a minimal number of arguments is the lowest cost model for these.
This is easily achieved with a format-string API that internally uses
`llvm::formatv`. This PR is essentially the `CHECK` version of #4283.

However, the check macros are substantially harder to make work with
both format strings and streaming because they also take a condition.
Also, unexpectedly, I was very successful at devising a regular
expression based automated rewrite from the streaming to the format
string form with only low 10s of manual fixes. This includes compacting
strings broken up across lines, etc. Given how well that went, I've
prepared this PR which just directly switches to the format string API
and migrate everything to use it.

One nice side-effect is that the format string approach ends up greatly
simplifying the implementation here as well.

This is ... *shockingly* effective. Parsing speeds up by more than 3%
with just this change. And checking speeds up by **8%** with this change
alone:
```
BM_CompileAPIFileDenseDecls<Phase::Parse>/256      86.3µs ± 1%  82.9µs ± 1%  -3.94%  (p=0.000 n=17+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/1024      431µs ± 1%   415µs ± 1%  -3.76%  (p=0.000 n=18+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/4096     1.77ms ± 1%  1.71ms ± 1%  -3.18%  (p=0.000 n=18+19)
BM_CompileAPIFileDenseDecls<Phase::Parse>/16384    7.44ms ± 1%  7.17ms ± 2%  -3.56%  (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Parse>/65536    30.7ms ± 1%  29.7ms ± 1%  -3.15%  (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Parse>/262144    131ms ± 1%   127ms ± 1%  -2.81%  (p=0.000 n=18+18)
BM_CompileAPIFileDenseDecls<Phase::Check>/256       878µs ± 2%   800µs ± 1%  -8.91%  (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/1024     1.88ms ± 2%  1.72ms ± 1%  -8.56%  (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/4096     5.78ms ± 2%  5.28ms ± 1%  -8.70%  (p=0.000 n=20+18)
BM_CompileAPIFileDenseDecls<Phase::Check>/16384    21.9ms ± 1%  20.1ms ± 1%  -8.02%  (p=0.000 n=18+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/65536    90.4ms ± 2%  83.1ms ± 1%  -8.04%  (p=0.000 n=19+20)
BM_CompileAPIFileDenseDecls<Phase::Check>/262144    381ms ± 2%   352ms ± 1%  -7.79%  (p=0.000 n=19+19)
```

---------

Co-authored-by: Richard Smith <richard@metafoo.co.uk>
Co-authored-by: josh11b <15258583+josh11b@users.noreply.github.com>
This commit is contained in:
Chandler Carruth
2024-09-12 16:42:08 +00:00
committed by GitHub
co-authored by Richard Smith josh11b
parent 35dfa5f03c
commit 4845f40dff
140 changed files with 1234 additions and 1161 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/lower/file_context.cpp
+12 -13
View File
@@ -38,13 +38,13 @@ FileContext::FileContext(llvm::LLVMContext& llvm_context,
sem_ir_(&sem_ir),
inst_namer_(inst_namer),
vlog_stream_(vlog_stream) {
CARBON_CHECK(!sem_ir.has_errors())
<< "Generating LLVM IR from invalid SemIR::File is unsupported.";
CARBON_CHECK(!sem_ir.has_errors(),
"Generating LLVM IR from invalid SemIR::File is unsupported.");
}
// TODO: Move this to lower.cpp.
auto FileContext::Run() -> std::unique_ptr<llvm::Module> {
CARBON_CHECK(llvm_module_) << "Run can only be called once.";
CARBON_CHECK(llvm_module_, "Run can only be called once.");
// Lower all types that were required to be complete.
types_.resize(sem_ir_->insts().size());
@@ -157,8 +157,8 @@ auto FileContext::GetGlobal(SemIR::InstId inst_id) -> llvm::Value* {
// TODO: For generics, handle references to symbolic constants.
CARBON_FATAL() << "Missing value: " << inst_id << " "
<< sem_ir().insts().Get(inst_id);
CARBON_FATAL("Missing value: {0} {1}", inst_id,
sem_ir().insts().Get(inst_id));
}
auto FileContext::BuildFunctionDecl(SemIR::FunctionId function_id)
@@ -187,7 +187,7 @@ auto FileContext::BuildFunctionDecl(SemIR::FunctionId function_id)
const auto return_info =
SemIR::ReturnTypeInfo::ForFunction(sem_ir(), function, specific_id);
CARBON_CHECK(return_info.is_valid()) << "Should not lower invalid functions.";
CARBON_CHECK(return_info.is_valid(), "Should not lower invalid functions.");
auto implicit_param_refs =
sem_ir().inst_blocks().GetOrEmpty(function.implicit_param_refs_id);
@@ -219,8 +219,7 @@ auto FileContext::BuildFunctionDecl(SemIR::FunctionId function_id)
switch (auto value_rep = SemIR::ValueRepr::ForType(sem_ir(), param_type_id);
value_rep.kind) {
case SemIR::ValueRepr::Unknown:
CARBON_FATAL()
<< "Incomplete parameter type lowering function declaration";
CARBON_FATAL("Incomplete parameter type lowering function declaration");
case SemIR::ValueRepr::None:
break;
case SemIR::ValueRepr::Copy:
@@ -364,8 +363,8 @@ auto FileContext::BuildDISubprogram(const SemIR::Function& function,
return nullptr;
}
auto name = sem_ir().names().GetAsStringIfIdentifier(function.name_id);
CARBON_CHECK(name) << "Unexpected special name for function: "
<< function.name_id;
CARBON_CHECK(name, "Unexpected special name for function: {0}",
function.name_id);
auto loc = GetLocForDI(function.definition_id);
// FIXME: Add more details here, including real subroutine type (once type
// information is built), etc.
@@ -390,7 +389,7 @@ static auto BuildTypeForInst(FileContext& context, SemIR::BuiltinInst inst)
-> llvm::Type* {
switch (inst.builtin_inst_kind) {
case SemIR::BuiltinInstKind::Invalid:
CARBON_FATAL() << "Unexpected builtin type in lowering.";
CARBON_FATAL("Unexpected builtin type in lowering.");
case SemIR::BuiltinInstKind::Error:
// This is a complete type but uses of it should never be lowered.
return nullptr;
@@ -423,7 +422,7 @@ template <typename InstT>
requires(InstT::Kind.is_type() == SemIR::InstIsType::Never)
static auto BuildTypeForInst(FileContext& /*context*/, InstT inst)
-> llvm::Type* {
CARBON_FATAL() << "Cannot use inst as type: " << inst;
CARBON_FATAL("Cannot use inst as type: {0}", inst);
}
static auto BuildTypeForInst(FileContext& context, SemIR::ClassType inst)
@@ -448,7 +447,7 @@ static auto BuildTypeForInst(FileContext& context, SemIR::IntType inst)
-> llvm::Type* {
auto width =
context.sem_ir().insts().TryGetAs<SemIR::IntLiteral>(inst.bit_width_id);
CARBON_CHECK(width) << "Can't lower int type with symbolic width";
CARBON_CHECK(width, "Can't lower int type with symbolic width");
return llvm::IntegerType::get(
context.llvm_context(),
context.sem_ir().ints().Get(width->int_id).getZExtValue());