Add --print-large-functions for checking which functions likely dominate the compile time.

releasenotes.md

@@ -15,6 +15,7 @@
 - Change typedef and const enums to not convert from literals by default.
 - Add `@constinit` to allow old typedef behaviour.
 - Include actual element count in the error message when the array initializer size does not match the expected size.
+- Add `--print-large-functions` for checking which functions likely dominate the compile time.
 
 ### Stdlib changes
 - Summarize sort macros as generic function wrappers to reduce the amount of generated code. #2831

src/build/build.h

@@ -210,6 +210,7 @@ typedef struct BuildOptions_
 	bool test_nosort;
 	bool test_noleak;
 	bool test_show_output;
+	bool print_large_functions;
 	const char *custom_linker_path;
 	uint32_t symtab_size;
 	unsigned version;
@@ -416,6 +417,7 @@ typedef struct
 	bool old_enums;
 	bool old_compact_eq;
 	bool single_threaded;
+	bool print_large_functions;
 	int build_threads;
 	TrustLevel trust_level;
 	OptimizationSetting optsetting;

src/build/build_options.c

@@ -140,6 +140,7 @@ static void usage(bool full)
 		print_opt("--use-old-slice-copy", "Use the old slice copy semantics.");
 		print_opt("--use-old-enums", "Use the old enum syntax and semantics.");
 		print_opt("--use-old-compact-eq", "Enable the old ability to use '@compact' to make a struct comparable.");
+		print_opt("--print-large-functions", "Print functions with large compile size.");
 		print_opt("--warn-deadcode=<yes|no|error>", "Print warning on dead-code: yes, no, error.");
 		print_opt("--warn-methodsnotresolved=<yes|no|error>", "Print warning on methods not resolved when accessed: yes, no, error.");
 		print_opt("--warn-deprecation=<yes|no|error>", "Print warning when using deprecated code and constructs: yes, no, error.");
@@ -895,6 +896,11 @@ static void parse_option(BuildOptions *options)
 				options->test_nosort = true;
 				return;
 			}
+			if (match_longopt("print-large-functions"))
+			{
+				options->print_large_functions = true;
+				return;
+			}
 			if ((argopt = match_argopt("warn-deadcode")))
 			{
 				options->warnings.dead_code = parse_opt_select(WarningLevel, argopt, warnings);

src/build/builder.c

@@ -429,6 +429,8 @@ static void update_build_target_from_options(BuildTarget *target, BuildOptions *
 	target->old_slice_copy = options->old_slice_copy;
 	target->old_enums = options->old_enums;
 	target->old_compact_eq = options->old_compact_eq;
+
+	target->print_large_functions = options->print_large_functions;
 	// Remove feature flags
 	FOREACH(const char *, remove_feature, options->removed_feature_names)
 	{

src/compiler/llvm_codegen_function.c

@@ -609,7 +609,15 @@ void llvm_emit_body(GenContext *c, LLVMValueRef function, FunctionPrototype *pro
 		c->debug.block_stack = NULL;
 		LLVMDIBuilderFinalizeSubprogram(c->debug.builder, c->debug.function);
 	}
-
+	if (compiler.build.print_large_functions)
+	{
+		unsigned instruction_count = LLVMGetFunctionInstructionCount(function);
+		if (instruction_count > 5000)
+		{
+			eprintf("%8u instructions found in %s:%s (%s) - function is very long.\n", instruction_count, decl->unit->module->name->module,
+				decl->name, decl->unit->file->full_path);
+		}
+	}
 	c->builder = prev_builder;
 	c->cur_func.ref = prev_function;
 }

src/compiler/sema_internal.h

@@ -51,14 +51,14 @@ const char *context_filename(SemaContext *context);
 AstId context_get_defers(SemaContext *context, AstId defer_bottom, bool is_success);
 void context_pop_defers(SemaContext *context, AstId *next);
 void context_pop_defers_and_replace_ast(SemaContext *context, Ast *ast);
-void context_change_scope_for_label(SemaContext *context, DeclId label, SourceSpan span);
+void context_change_scope_for_label(SemaContext *context, DeclId label_id, SourceSpan span);
 void context_change_scope_with_flags(SemaContext *context, ScopeFlags flags, SourceSpan span);
 SemaContext *context_transform_for_eval(SemaContext *context, SemaContext *temp_context, CompilationUnit *eval_unit);
 
 TokenType sema_splitpathref(const char *string, ArraySize len, Path **path_ref, const char **ident_ref);
-void sema_print_inline(SemaContext *context, SourceSpan span_original);
+void sema_print_inline(SemaContext *context, SourceSpan original);
 void sema_error_at(SemaContext *context, SourceSpan span, const char *message, ...);
-bool sema_warn_at(SemaContext *context, SourceSpan span, WarningLevel warning, const char *message, ...);
+bool sema_warn_at(SemaContext *context, SourceSpan span, WarningLevel level, const char *message, ...);
 
 void sema_context_init(SemaContext *context, CompilationUnit *unit);
 void sema_context_destroy(SemaContext *context);

test/unit/stdlib/core/builtintests.c3

@@ -225,7 +225,7 @@ macro test_hash_vector_macro_bool()
 	}
 	$endforeach
 }
-fn void test_hash_vector()
+fn void test_hash_vector() @if($feature(SLOW_TESTS))
 {
 	test_hash_vector_macro(char, ichar, short, ushort, int, uint, long, ulong, int128, uint128);
 	test_hash_vector_macro_bool();

wrapper/include/c3_llvm.h

@@ -81,6 +81,7 @@ void LLVMSetDSOLocal(LLVMValueRef Global, bool value);
 void LLVMSetTargetMachineUseInitArray(LLVMTargetMachineRef ref, bool use_init_array);
 void LLVMSetTargetMachineEmulatedTLS(LLVMTargetMachineRef ref, bool emulated_tls);
 void LLVMSetNoSanitizeAddress(LLVMValueRef Global);
+unsigned LLVMGetFunctionInstructionCount(LLVMValueRef function);
 
 #ifdef __cplusplus
 }

wrapper/src/wrapper.cpp

@@ -341,6 +341,11 @@ void LLVMSetNoSanitizeAddress(LLVMValueRef Global)
 	global->setSanitizerMetadata(data);
 }
 
+unsigned LLVMGetFunctionInstructionCount(LLVMValueRef function)
+{
+	auto func = llvm::unwrap<llvm::Function>(function);
+	return func->getInstructionCount();
+}
 void LLVMBuilderSetFastMathFlags(LLVMBuilderRef Builder, FastMathOption option)
 {
 	llvm::FastMathFlags math_flags {};