Implement instrumentation pass

1 files changed, 77 insertions, 0 deletions

diff --git a/src/llvm_backend_opt.cpp b/src/llvm_backend_opt.cpp
index 2e03b7974..d5487d259 100644
--- a/src/llvm_backend_opt.cpp
+++ b/src/llvm_backend_opt.cpp
@@ -380,6 +380,80 @@ gb_internal void lb_run_remove_dead_instruction_pass(lbProcedure *p) {
 	}
 }
 
+gb_internal LLVMValueRef lb_run_instrumentation_pass_insert_call(lbProcedure *p, Entity *entity, LLVMBuilderRef dummy_builder) {
+	lbModule *m = p->module;
+
+	lbValue cc = lb_find_procedure_value_from_entity(m, entity);
+
+	LLVMValueRef args[2] = {};
+	args[0] = p->value;
+
+	LLVMValueRef returnaddress_args[1] = {};
+
+	returnaddress_args[0] = LLVMConstInt(LLVMInt32TypeInContext(m->ctx), 0, false);
+
+	char const *instrinsic_name = "llvm.returnaddress";
+	unsigned id = LLVMLookupIntrinsicID(instrinsic_name, gb_strlen(instrinsic_name));
+	GB_ASSERT_MSG(id != 0, "Unable to find %s", instrinsic_name);
+	LLVMValueRef ip = LLVMGetIntrinsicDeclaration(m->mod, id, nullptr, 0);
+	LLVMTypeRef call_type = LLVMIntrinsicGetType(m->ctx, id, nullptr, 0);
+	args[1] = LLVMBuildCall2(dummy_builder, call_type, ip, returnaddress_args, gb_count_of(returnaddress_args), "");
+
+	LLVMTypeRef fnp = lb_type_internal_for_procedures_raw(p->module, entity->type);
+	return LLVMBuildCall2(dummy_builder, fnp, cc.value, args, 2, "");
+}
+
+
+gb_internal void lb_run_instrumentation_pass(lbProcedure *p) {
+	lbModule *m = p->module;
+	Entity *enter = m->info->instrumentation_enter_entity;
+	Entity *exit  = m->info->instrumentation_exit_entity;
+	if (enter == nullptr || exit == nullptr) {
+		return;
+	}
+	if (!(p->entity &&
+	      p->entity->kind == Entity_Procedure &&
+	      p->entity->Procedure.has_instrumentation)) {
+		return;
+	}
+
+#define LLVM_V_NAME(x) x, cast(unsigned)(gb_count_of(x)-1)
+
+	LLVMBuilderRef dummy_builder = LLVMCreateBuilderInContext(m->ctx);
+	defer (LLVMDisposeBuilder(dummy_builder));
+
+	LLVMBasicBlockRef entry_bb = p->entry_block->block;
+	LLVMPositionBuilder(dummy_builder, entry_bb, LLVMGetFirstInstruction(entry_bb));
+	lb_run_instrumentation_pass_insert_call(p, enter, dummy_builder);
+	LLVMRemoveStringAttributeAtIndex(p->value, LLVMAttributeIndex_FunctionIndex, LLVM_V_NAME("instrument-function-entry"));
+
+	unsigned bb_count = LLVMCountBasicBlocks(p->value);
+	LLVMBasicBlockRef *bbs = gb_alloc_array(temporary_allocator(), LLVMBasicBlockRef, bb_count);
+	LLVMGetBasicBlocks(p->value, bbs);
+	for (unsigned i = 0; i < bb_count; i++) {
+		LLVMBasicBlockRef bb = bbs[i];
+		LLVMValueRef terminator = LLVMGetBasicBlockTerminator(bb);
+		if (terminator == nullptr ||
+		    !LLVMIsAReturnInst(terminator)) {
+			continue;
+		}
+
+		// TODO(bill): getTerminatingMustTailCall()
+		// If T is preceded by a musttail call, that's the real terminator.
+		// if (CallInst *CI = BB.getTerminatingMustTailCall())
+		// 	T = CI;
+
+
+		LLVMPositionBuilderBefore(dummy_builder, terminator);
+		lb_run_instrumentation_pass_insert_call(p, exit, dummy_builder);
+	}
+
+	LLVMRemoveStringAttributeAtIndex(p->value, LLVMAttributeIndex_FunctionIndex, LLVM_V_NAME("instrument-function-exit"));
+
+#undef LLVM_V_NAME
+}
+
+
 
 gb_internal void lb_run_function_pass_manager(LLVMPassManagerRef fpm, lbProcedure *p, lbFunctionPassManagerKind pass_manager_kind) {
 	if (p == nullptr) {
@@ -401,6 +475,7 @@ gb_internal void lb_run_function_pass_manager(LLVMPassManagerRef fpm, lbProcedur
 	    }
 	    break;
 	}
+	lb_run_instrumentation_pass(p);
 
 	LLVMRunFunctionPassManager(fpm, p->value);
 }
@@ -552,3 +627,5 @@ gb_internal void lb_run_remove_unused_globals_pass(lbModule *m) {
 		}
 	}
 }
+
+