Function TestBinarySize

builder/sizes_test.go:34–74

Test whether code and data size is as expected for the given targets. This tests both the logic of loadProgramSize and checks that code size doesn't change unintentionally. If you find that code or data size is reduced, then great! You can reduce the number in this test. If you find that the code o

(t *testing.T)

// increase. If so, please consider whether this new feature is indeed worth the
// size increase for all users.
func TestBinarySize(t *testing.T) {
	if runtime.GOOS == "linux" && !hasBuiltinTools {
		// Debian LLVM packages are modified a bit and tend to produce
		// different machine code. Ideally we'd fix this (with some attributes
		// or something?), but for now skip it.
		t.Skip("Skip: using external LLVM version so binary size might differ")
	}

	// This is a small number of very diverse targets that we want to test.
	tests := []sizeTest{
		// microcontrollers
		{"hifive1b", "examples/echo", 3680, 280, 0, 2252},
		{"microbit", "examples/serial", 2694, 342, 8, 2248},
		{"wioterminal", "examples/pininterrupt", 7074, 1510, 120, 7248},

		// TODO: also check wasm. Right now this is difficult, because
		// wasm binaries are run through wasm-opt and therefore the
		// output varies by binaryen version.
	}
	for _, tc := range tests {
		tc := tc
		t.Run(tc.target+"/"+tc.path, func(t *testing.T) {
			t.Parallel()

			// Build the binary.
			result := buildBinary(t, tc.target, tc.path)

			// Check whether the size of the binary matches the expected size.
			sizes, err := loadProgramSize(result.Executable, nil)
			if err != nil {
				t.Fatal("could not read program size:", err)
			}
			if sizes.Code != tc.codeSize || sizes.ROData != tc.rodataSize || sizes.Data != tc.dataSize || sizes.BSS != tc.bssSize {
				t.Errorf("Unexpected code size when compiling: -target=%s %s", tc.target, tc.path)
				t.Errorf("            code rodata   data    bss")
				t.Errorf("expected: %6d %6d %6d %6d", tc.codeSize, tc.rodataSize, tc.dataSize, tc.bssSize)
				t.Errorf("actual:   %6d %6d %6d %6d", sizes.Code, sizes.ROData, sizes.Data, sizes.BSS)
			}
		})
	}
}

// Check that the -size=full flag attributes binary size to the correct package
// without filesystem paths and things like that.