1 files changed, 121 insertions, 0 deletions
diff --git a/src/stack_report.cpp b/src/stack_report.cpp
new file mode 100644
index 0000000000..3a0abd6cef
--- /dev/null
+++ b/src/stack_report.cpp
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2019 Andrew Kelley
+ *
+ * This file is part of zig, which is MIT licensed.
+ * See http://opensource.org/licenses/MIT
+ */
+
+#include "stack_report.hpp"
+
+static void tree_print(FILE *f, ZigType *ty, size_t indent);
+
+static void pretty_print_bytes(FILE *f, double n) {
+    if (n > 1024.0 * 1024.0 * 1024.0) {
+        fprintf(f, "%.02f GiB", n / 1024.0 / 1024.0 / 1024.0);
+        return;
+    }
+    if (n > 1024.0 * 1024.0) {
+        fprintf(f, "%.02f MiB", n / 1024.0 / 1024.0);
+        return;
+    }
+    if (n > 1024.0) {
+        fprintf(f, "%.02f KiB", n / 1024.0);
+        return;
+    }
+    fprintf(f, "%.02f bytes", n );
+    return;
+}
+
+static int compare_type_abi_sizes_desc(const void *a, const void *b) {
+    uint64_t size_a = (*(ZigType * const*)(a))->abi_size;
+    uint64_t size_b = (*(ZigType * const*)(b))->abi_size;
+    if (size_a > size_b)
+        return -1;
+    if (size_a < size_b)
+        return 1;
+    return 0;
+}
+
+static void start_child(FILE *f, size_t indent) {
+    fprintf(f, "\n");
+    for (size_t i = 0; i < indent; i += 1) {
+        fprintf(f, " ");
+    }
+}
+
+static void start_peer(FILE *f, size_t indent) {
+    fprintf(f, ",\n");
+    for (size_t i = 0; i < indent; i += 1) {
+        fprintf(f, " ");
+    }
+}
+
+static void tree_print_struct(FILE *f, ZigType *struct_type, size_t indent) {
+    ZigList<ZigType *> children = {};
+    uint64_t sum_from_fields = 0;
+    for (size_t i = 0; i < struct_type->data.structure.src_field_count; i += 1) {
+        TypeStructField *field = &struct_type->data.structure.fields[i];
+        children.append(field->type_entry);
+        sum_from_fields += field->type_entry->abi_size;
+    }
+    qsort(children.items, children.length, sizeof(ZigType *), compare_type_abi_sizes_desc);
+
+    start_peer(f, indent);
+    fprintf(f, "\"padding\": \"%" ZIG_PRI_u64 "\"", struct_type->abi_size - sum_from_fields);
+
+    start_peer(f, indent);
+    fprintf(f, "\"fields\": [");
+
+    for (size_t i = 0; i < children.length; i += 1) {
+        if (i == 0) {
+            start_child(f, indent + 1);
+        } else {
+            start_peer(f, indent + 1);
+        }
+        fprintf(f, "{");
+
+        ZigType *child_type = children.at(i);
+        tree_print(f, child_type, indent + 2);
+
+        start_child(f, indent + 1);
+        fprintf(f, "}");
+    }
+
+    start_child(f, indent);
+    fprintf(f, "]");
+}
+
+static void tree_print(FILE *f, ZigType *ty, size_t indent) {
+    start_child(f, indent);
+    fprintf(f, "\"type\": \"%s\"", buf_ptr(&ty->name));
+
+    start_peer(f, indent);
+    fprintf(f, "\"sizef\": \"");
+    pretty_print_bytes(f, ty->abi_size);
+    fprintf(f, "\"");
+
+    start_peer(f, indent);
+    fprintf(f, "\"size\": \"%" ZIG_PRI_u64 "\"", ty->abi_size);
+
+    switch (ty->id) {
+        case ZigTypeIdFnFrame:
+            return tree_print_struct(f, ty->data.frame.locals_struct, indent);
+        case ZigTypeIdStruct:
+            return tree_print_struct(f, ty, indent);
+        default:
+            start_child(f, indent);
+            return;
+    }
+}
+
+void zig_print_stack_report(CodeGen *g, FILE *f) {
+    if (g->largest_frame_fn == nullptr) {
+        fprintf(f, "{\"error\": \"No async function frames in entire compilation.\"}\n");
+        return;
+    }
+    fprintf(f, "{");
+    tree_print(f, g->largest_frame_fn->frame_type, 1);
+
+    start_child(f, 0);
+    fprintf(f, "}\n");
+}