cgo: add support for printf

GNUmakefile

@@ -806,6 +806,7 @@ build/release: tinygo gen-device wasi-libc $(if $(filter 1,$(USE_SYSTEM_BINARYEN
 	@mkdir -p build/release/tinygo/lib/CMSIS/CMSIS
 	@mkdir -p build/release/tinygo/lib/macos-minimal-sdk
 	@mkdir -p build/release/tinygo/lib/mingw-w64/mingw-w64-crt/lib-common
+	@mkdir -p build/release/tinygo/lib/mingw-w64/mingw-w64-crt/stdio
 	@mkdir -p build/release/tinygo/lib/mingw-w64/mingw-w64-headers/defaults
 	@mkdir -p build/release/tinygo/lib/musl/arch
 	@mkdir -p build/release/tinygo/lib/musl/crt
@@ -840,10 +841,12 @@ endif
 	@cp -rp lib/musl/src/include         build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/internal        build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/legacy          build/release/tinygo/lib/musl/src
+	@cp -rp lib/musl/src/locale          build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/linux           build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/malloc          build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/mman            build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/math            build/release/tinygo/lib/musl/src
+	@cp -rp lib/musl/src/multibyte       build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/signal          build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/stdio           build/release/tinygo/lib/musl/src
 	@cp -rp lib/musl/src/string          build/release/tinygo/lib/musl/src
@@ -853,6 +856,7 @@ endif
 	@cp -rp lib/mingw-w64/mingw-w64-crt/def-include                 build/release/tinygo/lib/mingw-w64/mingw-w64-crt
 	@cp -rp lib/mingw-w64/mingw-w64-crt/lib-common/api-ms-win-crt-* build/release/tinygo/lib/mingw-w64/mingw-w64-crt/lib-common
 	@cp -rp lib/mingw-w64/mingw-w64-crt/lib-common/kernel32.def.in  build/release/tinygo/lib/mingw-w64/mingw-w64-crt/lib-common
+	@cp -rp lib/mingw-w64/mingw-w64-crt/stdio/ucrt_*                build/release/tinygo/lib/mingw-w64/mingw-w64-crt/stdio
 	@cp -rp lib/mingw-w64/mingw-w64-headers/crt/                    build/release/tinygo/lib/mingw-w64/mingw-w64-headers
 	@cp -rp lib/mingw-w64/mingw-w64-headers/defaults/include        build/release/tinygo/lib/mingw-w64/mingw-w64-headers/defaults
 	@cp -rp lib/nrfx/*                   build/release/tinygo/lib/nrfx

builder/build.go

@@ -169,11 +169,12 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 		}
 		libcDependencies = append(libcDependencies, dummyCompileJob(path))
 	case "mingw-w64":
-		_, unlock, err := MinGW.load(config, tmpdir)
+		job, unlock, err := MinGW.load(config, tmpdir)
 		if err != nil {
 			return BuildResult{}, err
 		}
-		unlock()
+		defer unlock()
+		libcDependencies = append(libcDependencies, job)
 		libcDependencies = append(libcDependencies, makeMinGWExtraLibs(tmpdir, config.GOARCH())...)
 	case "":
 		// no library specified, so nothing to do

builder/builtins.go

@@ -8,14 +8,13 @@ import (
 	"github.com/tinygo-org/tinygo/goenv"
 )
 
-// These are the GENERIC_SOURCES according to CMakeList.txt.
 var genericBuiltins = []string{
+	// These are the GENERIC_SOURCES according to CMakeList.txt as of LLVM 17.
 	"absvdi2.c",
 	"absvsi2.c",
 	"absvti2.c",
 	"adddf3.c",
 	"addsf3.c",
-	"addtf3.c",
 	"addvdi3.c",
 	"addvsi3.c",
 	"addvti3.c",
@@ -40,12 +39,12 @@ var genericBuiltins = []string{
 	"divdf3.c",
 	"divdi3.c",
 	"divmoddi4.c",
+	//"divmodsi4.c", // see aeabiBuiltins
+	"divmodti4.c",
 	"divsc3.c",
 	"divsf3.c",
 	"divsi3.c",
-	"divtc3.c",
 	"divti3.c",
-	"divtf3.c",
 	"extendsfdf2.c",
 	"extendhfsf2.c",
 	"ffsdi2.c",
@@ -91,7 +90,6 @@ var genericBuiltins = []string{
 	"mulsc3.c",
 	"mulsf3.c",
 	"multi3.c",
-	"multf3.c",
 	"mulvdi3.c",
 	"mulvsi3.c",
 	"mulvti3.c",
@@ -111,13 +109,11 @@ var genericBuiltins = []string{
 	"popcountti2.c",
 	"powidf2.c",
 	"powisf2.c",
-	"powitf2.c",
 	"subdf3.c",
 	"subsf3.c",
 	"subvdi3.c",
 	"subvsi3.c",
 	"subvti3.c",
-	"subtf3.c",
 	"trampoline_setup.c",
 	"truncdfhf2.c",
 	"truncdfsf2.c",
@@ -126,12 +122,43 @@ var genericBuiltins = []string{
 	"ucmpti2.c",
 	"udivdi3.c",
 	"udivmoddi4.c",
+	//"udivmodsi4.c", // see aeabiBuiltins
 	"udivmodti4.c",
 	"udivsi3.c",
 	"udivti3.c",
 	"umoddi3.c",
 	"umodsi3.c",
 	"umodti3.c",
+
+	// These are the GENERIC_TF_SOURCES as of LLVM 17.
+	// They are not needed on all platforms (32-bit platforms usually don't need
+	// these) but they seem to compile fine so it's easier to include them.
+	"addtf3.c",
+	"comparetf2.c",
+	"divtc3.c",
+	"divtf3.c",
+	"extenddftf2.c",
+	"extendhftf2.c",
+	"extendsftf2.c",
+	"fixtfdi.c",
+	"fixtfsi.c",
+	"fixtfti.c",
+	"fixunstfdi.c",
+	"fixunstfsi.c",
+	"fixunstfti.c",
+	"floatditf.c",
+	"floatsitf.c",
+	"floattitf.c",
+	"floatunditf.c",
+	"floatunsitf.c",
+	"floatuntitf.c",
+	"multc3.c",
+	"multf3.c",
+	"powitf2.c",
+	"subtf3.c",
+	"trunctfdf2.c",
+	"trunctfhf2.c",
+	"trunctfsf2.c",
 }
 
 var aeabiBuiltins = []string{

builder/mingw-w64.go

@@ -27,14 +27,30 @@ var MinGW = Library{
 		_, err = io.Copy(outf, inf)
 		return err
 	},
-	sourceDir: func() string { return "" }, // unused
+	sourceDir: func() string { return filepath.Join(goenv.Get("TINYGOROOT"), "lib/mingw-w64") },
 	cflags: func(target, headerPath string) []string {
-		// No flags necessary because there are no files to compile.
-		return nil
+		mingwDir := filepath.Join(goenv.Get("TINYGOROOT"), "lib/mingw-w64")
+		return []string{
+			"-nostdlibinc",
+			"-isystem", mingwDir + "/mingw-w64-headers/crt",
+			"-I", mingwDir + "/mingw-w64-headers/defaults/include",
+			"-I" + headerPath,
+		}
 	},
 	librarySources: func(target string) ([]string, error) {
-		// We only use the UCRT DLL file. No source files necessary.
-		return nil, nil
+		// These files are needed so that printf and the like are supported.
+		sources := []string{
+			"mingw-w64-crt/stdio/ucrt_fprintf.c",
+			"mingw-w64-crt/stdio/ucrt_fwprintf.c",
+			"mingw-w64-crt/stdio/ucrt_printf.c",
+			"mingw-w64-crt/stdio/ucrt_snprintf.c",
+			"mingw-w64-crt/stdio/ucrt_sprintf.c",
+			"mingw-w64-crt/stdio/ucrt_vfprintf.c",
+			"mingw-w64-crt/stdio/ucrt_vprintf.c",
+			"mingw-w64-crt/stdio/ucrt_vsnprintf.c",
+			"mingw-w64-crt/stdio/ucrt_vsprintf.c",
+		}
+		return sources, nil
 	},
 }
 

builder/musl.go

@@ -92,6 +92,8 @@ var Musl = Library{
 			"-Wno-ignored-pragmas",
 			"-Wno-tautological-constant-out-of-range-compare",
 			"-Wno-deprecated-non-prototype",
+			"-Wno-format",
+			"-Wno-parentheses",
 			"-Qunused-arguments",
 			// Select include dirs. Don't include standard library includes
 			// (that would introduce host dependencies and other complications),
@@ -119,11 +121,13 @@ var Musl = Library{
 			"internal/syscall_ret.c",
 			"internal/vdso.c",
 			"legacy/*.c",
+			"locale/*.c",
 			"linux/*.c",
 			"malloc/*.c",
 			"malloc/mallocng/*.c",
 			"mman/*.c",
 			"math/*.c",
+			"multibyte/*.c",
 			"signal/*.c",
 			"stdio/*.c",
 			"string/*.c",

builder/picolibc.go

@@ -29,6 +29,7 @@ var Picolibc = Library{
 			"-D_HAVE_ALIAS_ATTRIBUTE",
 			"-DTINY_STDIO",
 			"-DPOSIX_IO",
+			"-DFORMAT_DEFAULT_INTEGER", // use __i_vfprintf and __i_vfscanf by default
 			"-D_IEEE_LIBM",
 			"-D__OBSOLETE_MATH_FLOAT=1", // use old math code that doesn't expect a FPU
 			"-D__OBSOLETE_MATH_DOUBLE=0",

src/runtime/runtime_tinygowasm.go

@@ -21,6 +21,11 @@ func fd_write(id uint32, iovs *__wasi_iovec_t, iovs_len uint, nwritten *uint) (e
 //go:wasmimport wasi_snapshot_preview1 proc_exit
 func proc_exit(exitcode uint32)
 
+// Flush stdio on exit.
+//
+//export __stdio_exit
+func __stdio_exit()
+
 const (
 	putcharBufferSize = 120
 	stdout            = 1
@@ -72,6 +77,9 @@ func abort() {
 
 //go:linkname syscall_Exit syscall.Exit
 func syscall_Exit(code int) {
+	// TODO: should we call __stdio_exit here?
+	// It's a low-level exit (syscall.Exit) so doing any libc stuff seems
+	// unexpected, but then where else should stdio buffers be flushed?
 	proc_exit(uint32(code))
 }
 

src/runtime/runtime_wasm_js.go

@@ -18,6 +18,7 @@ func _start() {
 
 	wasmNested = true
 	run()
+	__stdio_exit()
 	wasmNested = false
 }
 

src/runtime/runtime_wasm_wasi.go

@@ -19,6 +19,7 @@ func _start() {
 	heapStart = uintptr(unsafe.Pointer(&heapStartSymbol))
 	heapEnd = uintptr(wasm_memory_size(0) * wasmPageSize)
 	run()
+	__stdio_exit()
 }
 
 // Read the command line arguments from WASI.

testdata/cgo/main.c

@@ -1,4 +1,5 @@
 #include "main.h"
+#include <stdio.h>
 
 int global = 3;
 bool globalBool = 1;
@@ -67,3 +68,7 @@ void unionSetData(short f0, short f1, short f2) {
 void arraydecay(int buf1[5], int buf2[3][8], int buf3[4][7][2]) {
 	// Do nothing.
 }
+
+void printf_single_int(char *format, int arg) {
+	printf(format, arg);
+}

testdata/cgo/main.go

@@ -174,6 +174,10 @@ func main() {
 	// libc: test basic stdio functionality
 	putsBuf := []byte("line written using C puts\x00")
 	C.puts((*C.char)(unsafe.Pointer(&putsBuf[0])))
+
+	// libc: test whether printf works in C.
+	printfBuf := []byte("line written using C printf with value=%d\n\x00")
+	C.printf_single_int((*C.char)(unsafe.Pointer(&printfBuf[0])), -21)
 }
 
 func printUnion(union C.joined_t) C.joined_t {

testdata/cgo/main.h

@@ -150,3 +150,5 @@ extern int global;
 // Test array decaying into a pointer.
 typedef int arraydecay_buf3[4][7][2];
 void arraydecay(int buf1[5], int buf2[3][8], arraydecay_buf3 buf3);
+
+void printf_single_int(char *format, int arg);

testdata/cgo/out.txt

@@ -75,3 +75,4 @@ len(C.GoStringN(nil, 0)): 0
 len(C.GoBytes(nil, 0)): 0
 copied string: foobar
 line written using C puts
+line written using C printf with value=-21