First pass at adding metering

rdunnington · Jun 7, 2024 · 8ef7271 · 8ef7271
1 parent 711dc99
commit 8ef7271
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Showing 5 changed files with 549 additions and 459 deletions.
diff --git a/build.zig b/build.zig
@@ -13,11 +13,16 @@ const ExeOpts = struct {
     description: []const u8,
     step_dependencies: ?[]*Build.Step = null,
     should_emit_asm: bool = false,
+    options: *Build.Step.Options,
 };
 
 pub fn build(b: *Build) void {
     const should_emit_asm = b.option(bool, "asm", "Emit asm for the bytebox binaries") orelse false;
     const no_clang = b.option(bool, "noclang", "Pass this if clang isn't in the PATH") orelse false;
+    const enable_metering = b.option(bool, "meter", "Enable metering") orelse false;
+
+    const options = b.addOptions();
+    options.addOption(bool, "enable_metering", enable_metering);
 
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
@@ -38,6 +43,8 @@ pub fn build(b: *Build) void {
         .imports = &[_]ModuleImport{stable_array_import},
     });
 
+    bytebox_module.addOptions("config", options);
+
     // exe.root_module.addImport(import.name, import.module);
 
     const imports = [_]ModuleImport{
@@ -51,6 +58,7 @@ pub fn build(b: *Build) void {
         .step_name = "run",
         .description = "Run a wasm program",
         .should_emit_asm = should_emit_asm,
+        .options = options,
     });
 
     var bench_steps = [_]*Build.Step{
@@ -64,6 +72,7 @@ pub fn build(b: *Build) void {
         .step_name = "bench",
         .description = "Run the benchmark suite",
         .step_dependencies = &bench_steps,
+        .options = options,
     });
 
     const lib_bytebox: *Build.Step.Compile = b.addStaticLibrary(.{
@@ -73,6 +82,7 @@ pub fn build(b: *Build) void {
         .optimize = optimize,
     });
     lib_bytebox.root_module.addImport(stable_array_import.name, stable_array_import.module);
+    lib_bytebox.root_module.addOptions("config", options);
     lib_bytebox.installHeader(b.path("src/bytebox.h"), "bytebox.h");
     b.installArtifact(lib_bytebox);
 
@@ -83,6 +93,7 @@ pub fn build(b: *Build) void {
         .optimize = optimize,
     });
     unit_tests.root_module.addImport(stable_array_import.name, stable_array_import.module);
+    unit_tests.root_module.addOptions("config", options);
     const run_unit_tests = b.addRunArtifact(unit_tests);
     const unit_test_step = b.step("test-unit", "Run unit tests");
     unit_test_step.dependOn(&run_unit_tests.step);
@@ -93,6 +104,7 @@ pub fn build(b: *Build) void {
         .root_src = "test/wasm/main.zig",
         .step_name = "test-wasm",
         .description = "Run the wasm testsuite",
+        .options = options,
     });
 
     // wasi tests
@@ -127,6 +139,7 @@ pub fn build(b: *Build) void {
             .root_src = "test/mem64/main.zig",
             .step_name = "test-mem64",
             .description = "Run the mem64 test",
+            .options = options,
         });
     }
 
@@ -151,6 +164,7 @@ fn buildExeWithRunStep(b: *Build, target: Build.ResolvedTarget, optimize: std.bu
     for (imports) |import| {
         exe.root_module.addImport(import.name, import.module);
     }
+    exe.root_module.addOptions("config", opts.options);
 
     // exe.emit_asm = if (opts.should_emit_asm) .emit else .default;
     b.installArtifact(exe);

diff --git a/src/instance.zig b/src/instance.zig
@@ -3,6 +3,8 @@ const AllocError = std.mem.Allocator.Error;
 
 const builtin = @import("builtin");
 
+const metering = @import("metering.zig");
+
 const common = @import("common.zig");
 const StableArray = common.StableArray;
 const Logger = common.Logger;
@@ -57,7 +59,7 @@ pub const TrapError = error{
     TrapOutOfBoundsTableAccess,
     TrapStackExhausted,
     TrapUnknown,
-};
+} || metering.MeteringTrapError;
 
 pub const DebugTrace = struct {
     pub const Mode = enum {
@@ -616,6 +618,10 @@ pub const ModuleInstantiateOpts = struct {
 
 pub const InvokeOpts = struct {
     trap_on_start: bool = false,
+    meter: metering.Meter = metering.initial_meter,
+};
+pub const ResumeInvokeOpts = struct {
+    meter: metering.Meter = metering.initial_meter,
 };
 
 pub const DebugTrapInstructionMode = enum {
@@ -629,7 +635,7 @@ pub const VM = struct {
     const InstantiateFn = *const fn (vm: *VM, module: *ModuleInstance, opts: ModuleInstantiateOpts) anyerror!void;
     const InvokeFn = *const fn (vm: *VM, module: *ModuleInstance, handle: FunctionHandle, params: [*]const Val, returns: [*]Val, opts: InvokeOpts) anyerror!void;
     const InvokeWithIndexFn = *const fn (vm: *VM, module: *ModuleInstance, func_index: usize, params: [*]const Val, returns: [*]Val) anyerror!void;
-    const ResumeInvokeFn = *const fn (vm: *VM, module: *ModuleInstance, returns: []Val) anyerror!void;
+    const ResumeInvokeFn = *const fn (vm: *VM, module: *ModuleInstance, returns: []Val, opts: ResumeInvokeOpts) anyerror!void;
     const StepFn = *const fn (vm: *VM, module: *ModuleInstance, returns: []Val) anyerror!void;
     const SetDebugTrapFn = *const fn (vm: *VM, module: *ModuleInstance, wasm_address: u32, mode: DebugTrapInstructionMode) anyerror!bool;
     const FormatBacktraceFn = *const fn (vm: *VM, indent: u8, allocator: std.mem.Allocator) anyerror!std.ArrayList(u8);
@@ -699,8 +705,8 @@ pub const VM = struct {
         try vm.invoke_with_index_fn(vm, module, func_index, params, returns);
     }
 
-    pub fn resumeInvoke(vm: *VM, module: *ModuleInstance, returns: []Val) anyerror!void {
-        try vm.resume_invoke_fn(vm, module, returns);
+    pub fn resumeInvoke(vm: *VM, module: *ModuleInstance, returns: []Val, opts: ResumeInvokeOpts) anyerror!void {
+        try vm.resume_invoke_fn(vm, module, returns, opts);
     }
 
     pub fn step(vm: *VM, module: *ModuleInstance, returns: []Val) anyerror!void {
@@ -1186,8 +1192,8 @@ pub const ModuleInstance = struct {
     }
 
     /// Use to resume an invoked function after it returned error.DebugTrap
-    pub fn resumeInvoke(self: *ModuleInstance, returns: []Val) anyerror!void {
-        try self.vm.resumeInvoke(self, returns);
+    pub fn resumeInvoke(self: *ModuleInstance, returns: []Val, opts: ResumeInvokeOpts) anyerror!void {
+        try self.vm.resumeInvoke(self, returns, opts);
     }
 
     pub fn step(self: *ModuleInstance, returns: []Val) anyerror!void {

diff --git a/src/metering.zig b/src/metering.zig
@@ -0,0 +1,20 @@
+const config = @import("config");
+const Instruction = @import("definition.zig").Instruction;
+
+pub const enabled = config.enable_metering;
+
+pub const Meter = if (enabled) usize else void;
+
+pub const initial_meter = if (enabled) 0 else {};
+
+pub const MeteringTrapError = if (enabled) error{TrapMeterExceeded} else error{};
+
+pub fn reduce(fuel: Meter, instruction: Instruction) Meter {
+    if (fuel == 0) {
+        return fuel;
+    }
+    return switch (instruction.opcode) {
+        .Invalid, .Unreachable, .DebugTrap, .Noop, .Block, .Loop, .If, .IfNoElse, .Else, .End, .Branch, .Branch_If, .Branch_Table, .Drop => fuel,
+        else => fuel - 1,
+    };
+}
diff --git a/src/vm_register.zig b/src/vm_register.zig
@@ -56,6 +56,7 @@ const inst = @import("instance.zig");
 const VM = inst.VM;
 const ModuleInstance = inst.ModuleInstance;
 const InvokeOpts = inst.InvokeOpts;
+const ResumeInvokeOpts = inst.ResumeInvokeOpts;
 const DebugTrapInstructionMode = inst.DebugTrapInstructionMode;
 const ModuleInstantiateOpts = inst.ModuleInstantiateOpts;
 
@@ -1131,10 +1132,11 @@ pub const RegisterVM = struct {
         return error.Unimplemented;
     }
 
-    pub fn resumeInvoke(vm: *VM, module: *ModuleInstance, returns: []Val) anyerror!void {
+    pub fn resumeInvoke(vm: *VM, module: *ModuleInstance, returns: []Val, opts: ResumeInvokeOpts) anyerror!void {
         _ = vm;
         _ = module;
         _ = returns;
+        _ = opts;
         return error.Unimplemented;
     }