all: add target-features string to all targets

This makes sure that the LLVM target features match the one generated by
Clang:

  - This fixes a bug introduced when setting the target CPU for all
    targets: Cortex-M4 would now start using floating point operations
    while they were disabled in C.
  - This will make it possible in the future to inline C functions in Go
    and vice versa. This will need some more work though.

There is a code size impact. Cortex-M4 targets are increased slightly in
binary size while Cortex-M0 targets tend to be reduced a little bit.
Other than that, there is little impact.

builder/build.go

@@ -136,7 +136,6 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(Buil
 		DefaultStackSize:   config.Target.DefaultStackSize,
 		NeedsStackObjects:  config.NeedsStackObjects(),
 		Debug:              true,
-		LLVMFeatures:       config.LLVMFeatures(),
 	}
 
 	// Load the target machine, which is the LLVM object that contains all

builder/builder_test.go

@@ -12,8 +12,8 @@ import (
 	"tinygo.org/x/go-llvm"
 )
 
-// Test whether the Clang generated "target-cpu" attribute matches the CPU
-// property in TinyGo target files.
+// Test whether the Clang generated "target-cpu" and "target-features"
+// attributes match the CPU and Features property in TinyGo target files.
 func TestClangAttributes(t *testing.T) {
 	var targetNames = []string{
 		// Please keep this list sorted!
@@ -112,16 +112,30 @@ func testClangAttributes(t *testing.T, options *compileopts.Options) {
 		t.Errorf("target has LLVM triple %#v but Clang makes it LLVM triple %#v", config.Triple(), mod.Target())
 	}
 
-	// Check the "target-cpu"  string attribute of the add function.
+	// Check the "target-cpu" and "target-features" string attribute of the add
+	// function.
 	add := mod.NamedFunction("add")
-	var cpu string
+	var cpu, features string
 	cpuAttr := add.GetStringAttributeAtIndex(-1, "target-cpu")
+	featuresAttr := add.GetStringAttributeAtIndex(-1, "target-features")
 	if !cpuAttr.IsNil() {
 		cpu = cpuAttr.GetStringValue()
 	}
+	if !featuresAttr.IsNil() {
+		features = featuresAttr.GetStringValue()
+	}
 	if cpu != config.CPU() {
 		t.Errorf("target has CPU %#v but Clang makes it CPU %#v", config.CPU(), cpu)
 	}
+	if features != config.Features() {
+		if llvm.Version != "11.0.0" {
+			// This needs to be removed once we switch to LLVM 12.
+			// LLVM 11.0.0 uses a different "target-features" string than LLVM
+			// 11.1.0 for Thumb targets. The Xtensa fork is still based on LLVM
+			// 11.0.0, so we need to skip this check on that version.
+			t.Errorf("target has LLVM features %#v but Clang makes it %#v", config.Features(), features)
+		}
+	}
 }
 
 // This TestMain is necessary because TinyGo may also be invoked to run certain

compileopts/config.go

@@ -34,10 +34,16 @@ func (c *Config) CPU() string {
 }
 
 // Features returns a list of features this CPU supports. For example, for a
-// RISC-V processor, that could be ["+a", "+c", "+m"]. For many targets, an
-// empty list will be returned.
-func (c *Config) Features() []string {
-	return c.Target.Features
+// RISC-V processor, that could be "+a,+c,+m". For many targets, an empty list
+// will be returned.
+func (c *Config) Features() string {
+	if c.Target.Features == "" {
+		return c.Options.LLVMFeatures
+	}
+	if c.Options.LLVMFeatures == "" {
+		return c.Target.Features
+	}
+	return c.Target.Features + "," + c.Options.LLVMFeatures
 }
 
 // GOOS returns the GOOS of the target. This might not always be the actual OS:
@@ -441,10 +447,6 @@ func (c *Config) WasmAbi() string {
 	return c.Target.WasmAbi
 }
 
-func (c *Config) LLVMFeatures() string {
-	return c.Options.LLVMFeatures
-}
-
 type TestConfig struct {
 	CompileTestBinary bool
 	// TODO: Filter the test functions to run, include verbose flag, etc

compileopts/target.go

@@ -25,7 +25,7 @@ type TargetSpec struct {
 	Inherits         []string `json:"inherits"`
 	Triple           string   `json:"llvm-target"`
 	CPU              string   `json:"cpu"`
-	Features         []string `json:"features"`
+	Features         string   `json:"features"`
 	GOOS             string   `json:"goos"`
 	GOARCH           string   `json:"goarch"`
 	BuildTags        []string `json:"build-tags"`
@@ -234,12 +234,16 @@ func defaultTarget(goos, goarch, triple string) (*TargetSpec, error) {
 	switch goarch {
 	case "386":
 		spec.CPU = "pentium4"
+		spec.Features = "+cx8,+fxsr,+mmx,+sse,+sse2,+x87"
 	case "amd64":
 		spec.CPU = "x86-64"
+		spec.Features = "+cx8,+fxsr,+mmx,+sse,+sse2,+x87"
 	case "arm":
 		spec.CPU = "generic"
+		spec.Features = "+armv7-a,+dsp,+fp64,+vfp2,+vfp2sp,+vfp3d16,+vfp3d16sp,-thumb-mode"
 	case "arm64":
 		spec.CPU = "generic"
+		spec.Features = "+neon"
 	}
 	if goos == "darwin" {
 		spec.CFlags = append(spec.CFlags, "-isysroot", "/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk")

compiler/compiler.go

@@ -43,7 +43,7 @@ type Config struct {
 	// Target and output information.
 	Triple          string
 	CPU             string
-	Features        []string
+	Features        string
 	GOOS            string
 	GOARCH          string
 	CodeModel       string
@@ -57,7 +57,6 @@ type Config struct {
 	DefaultStackSize   uint64
 	NeedsStackObjects  bool
 	Debug              bool // Whether to emit debug information in the LLVM module.
-	LLVMFeatures       string
 }
 
 // compilerContext contains function-independent data that should still be
@@ -189,12 +188,6 @@ func NewTargetMachine(config *Config) (llvm.TargetMachine, error) {
 		return llvm.TargetMachine{}, err
 	}
 
-	feat := config.Features
-	if len(config.LLVMFeatures) > 0 {
-		feat = append(feat, config.LLVMFeatures)
-	}
-	features := strings.Join(feat, ",")
-
 	var codeModel llvm.CodeModel
 	var relocationModel llvm.RelocMode
 
@@ -222,7 +215,7 @@ func NewTargetMachine(config *Config) (llvm.TargetMachine, error) {
 		relocationModel = llvm.RelocDynamicNoPic
 	}
 
-	machine := target.CreateTargetMachine(config.Triple, config.CPU, features, llvm.CodeGenLevelDefault, relocationModel, codeModel)
+	machine := target.CreateTargetMachine(config.Triple, config.CPU, config.Features, llvm.CodeGenLevelDefault, relocationModel, codeModel)
 	return machine, nil
 }
 

targets/cortex-m0.json

@@ -1,5 +1,6 @@
 {
 	"inherits": ["cortex-m"],
 	"llvm-target": "thumbv6m-unknown-unknown-eabi",
-	"cpu": "cortex-m0"
+	"cpu": "cortex-m0",
+	"features": "+armv6-m,+soft-float,+strict-align,+thumb-mode,-aes,-bf16,-cdecp0,-cdecp1,-cdecp2,-cdecp3,-cdecp4,-cdecp5,-cdecp6,-cdecp7,-crc,-crypto,-d32,-dotprod,-dsp,-fp-armv8,-fp-armv8d16,-fp-armv8d16sp,-fp-armv8sp,-fp16,-fp16fml,-fp64,-fpregs,-fullfp16,-hwdiv,-hwdiv-arm,-i8mm,-lob,-mve,-mve.fp,-neon,-ras,-sb,-sha2,-vfp2,-vfp2sp,-vfp3,-vfp3d16,-vfp3d16sp,-vfp3sp,-vfp4,-vfp4d16,-vfp4d16sp,-vfp4sp"
 }

targets/cortex-m0plus.json

@@ -1,5 +1,6 @@
 {
 	"inherits": ["cortex-m"],
 	"llvm-target": "thumbv6m-unknown-unknown-eabi",
-	"cpu": "cortex-m0plus"
+	"cpu": "cortex-m0plus",
+	"features": "+armv6-m,+soft-float,+strict-align,+thumb-mode,-aes,-bf16,-cdecp0,-cdecp1,-cdecp2,-cdecp3,-cdecp4,-cdecp5,-cdecp6,-cdecp7,-crc,-crypto,-d32,-dotprod,-dsp,-fp-armv8,-fp-armv8d16,-fp-armv8d16sp,-fp-armv8sp,-fp16,-fp16fml,-fp64,-fpregs,-fullfp16,-hwdiv,-hwdiv-arm,-i8mm,-lob,-mve,-mve.fp,-neon,-ras,-sb,-sha2,-vfp2,-vfp2sp,-vfp3,-vfp3d16,-vfp3d16sp,-vfp3sp,-vfp4,-vfp4d16,-vfp4d16sp,-vfp4sp"
 }

targets/cortex-m3.json

@@ -1,5 +1,6 @@
 {
 	"inherits": ["cortex-m"],
 	"llvm-target": "thumbv7m-unknown-unknown-eabi",
-	"cpu": "cortex-m3"
+	"cpu": "cortex-m3",
+	"features": "+armv7-m,+hwdiv,+soft-float,+strict-align,+thumb-mode,-aes,-bf16,-cdecp0,-cdecp1,-cdecp2,-cdecp3,-cdecp4,-cdecp5,-cdecp6,-cdecp7,-crc,-crypto,-d32,-dotprod,-dsp,-fp-armv8,-fp-armv8d16,-fp-armv8d16sp,-fp-armv8sp,-fp16,-fp16fml,-fp64,-fpregs,-fullfp16,-hwdiv-arm,-i8mm,-lob,-mve,-mve.fp,-neon,-ras,-sb,-sha2,-vfp2,-vfp2sp,-vfp3,-vfp3d16,-vfp3d16sp,-vfp3sp,-vfp4,-vfp4d16,-vfp4d16sp,-vfp4sp"
 }

targets/cortex-m4.json

@@ -2,6 +2,7 @@
 	"inherits": ["cortex-m"],
 	"llvm-target": "thumbv7em-unknown-unknown-eabi",
 	"cpu": "cortex-m4",
+	"features": "+armv7e-m,+dsp,+hwdiv,+soft-float,+strict-align,+thumb-mode,-aes,-bf16,-cdecp0,-cdecp1,-cdecp2,-cdecp3,-cdecp4,-cdecp5,-cdecp6,-cdecp7,-crc,-crypto,-d32,-dotprod,-fp-armv8,-fp-armv8d16,-fp-armv8d16sp,-fp-armv8sp,-fp16,-fp16fml,-fp64,-fpregs,-fullfp16,-hwdiv-arm,-i8mm,-lob,-mve,-mve.fp,-neon,-ras,-sb,-sha2,-vfp2,-vfp2sp,-vfp3,-vfp3d16,-vfp3d16sp,-vfp3sp,-vfp4,-vfp4d16,-vfp4d16sp,-vfp4sp",
 	"cflags": [
 		"-mfloat-abi=soft"
 	]

targets/cortex-m7.json

@@ -2,6 +2,7 @@
 	"inherits": ["cortex-m"],
 	"llvm-target": "thumbv7em-unknown-unknown-eabi",
 	"cpu": "cortex-m7",
+	"features": "+armv7e-m,+dsp,+hwdiv,+soft-float,+strict-align,+thumb-mode,-aes,-bf16,-cdecp0,-cdecp1,-cdecp2,-cdecp3,-cdecp4,-cdecp5,-cdecp6,-cdecp7,-crc,-crypto,-d32,-dotprod,-fp-armv8,-fp-armv8d16,-fp-armv8d16sp,-fp-armv8sp,-fp16,-fp16fml,-fp64,-fpregs,-fullfp16,-hwdiv-arm,-i8mm,-lob,-mve,-mve.fp,-neon,-ras,-sb,-sha2,-vfp2,-vfp2sp,-vfp3,-vfp3d16,-vfp3d16sp,-vfp3sp,-vfp4,-vfp4d16,-vfp4d16sp,-vfp4sp",
 	"cflags": [
 		"-mfloat-abi=soft"
 	]

targets/esp32c3.json

@@ -1,10 +1,13 @@
 {
 	"inherits": ["riscv32"],
-	"features": ["+c", "+m"],
+	"features": "+c,+m,-relax,-save-restore",
 	"build-tags": ["esp32c3", "esp"],
 	"serial": "uart",
 	"rtlib": "compiler-rt",
 	"libc": "picolibc",
+	"cflags": [
+		"-march=rv32imc"
+	],
 	"linkerscript": "targets/esp32c3.ld",
 	"extra-files": [
 		"src/device/esp/esp32c3.S"

targets/fe310.json

@@ -1,6 +1,6 @@
 {
 	"inherits": ["riscv32"],
 	"cpu": "sifive-e31",
-	"features": ["+a", "+c", "+m"],
+	"features": "+a,+c,+m,-64bit,-relax,-save-restore",
 	"build-tags": ["fe310", "sifive"]
 }

targets/gameboy-advance.json

@@ -1,6 +1,7 @@
 {
 	"llvm-target": "armv4t-unknown-unknown-eabi",
 	"cpu": "arm7tdmi",
+	"features": "+armv4t,+soft-float,+strict-align,-aes,-bf16,-cdecp0,-cdecp1,-cdecp2,-cdecp3,-cdecp4,-cdecp5,-cdecp6,-cdecp7,-crc,-crypto,-d32,-dotprod,-dsp,-fp-armv8,-fp-armv8d16,-fp-armv8d16sp,-fp-armv8sp,-fp16,-fp16fml,-fp64,-fpregs,-fullfp16,-hwdiv,-hwdiv-arm,-i8mm,-lob,-mve,-mve.fp,-neon,-ras,-sb,-sha2,-thumb-mode,-vfp2,-vfp2sp,-vfp3,-vfp3d16,-vfp3d16sp,-vfp3sp,-vfp4,-vfp4d16,-vfp4d16sp,-vfp4sp",
 	"build-tags": ["gameboyadvance", "arm7tdmi", "baremetal", "linux", "arm"],
 	"goos": "linux",
 	"goarch": "arm",

targets/k210.json

@@ -1,6 +1,6 @@
 {
 	"inherits": ["riscv64"],
-	"features": ["+a", "+c", "+m", "+f", "+d"],
+	"features": "+a,+c,+d,+f,+m,-relax,-save-restore",
 	"build-tags": ["k210", "kendryte"],
 	"code-model": "medium"
 }

targets/nintendoswitch.json

@@ -1,6 +1,7 @@
 {
   "llvm-target": "aarch64",
   "cpu": "cortex-a57",
+  "features": "+aes,+crc,+crypto,+fp-armv8,+neon,+sha2",
   "build-tags": ["nintendoswitch", "arm64"],
   "scheduler": "tasks",
   "goos": "linux",

targets/riscv-qemu.json

@@ -1,6 +1,6 @@
 {
 	"inherits": ["riscv32"],
-	"features": ["+a", "+c", "+m"],
+	"features": "+a,+c,+m,-relax,-save-restore",
 	"build-tags": ["virt", "qemu"],
 	"linkerscript": "targets/riscv-qemu.ld",
 	"emulator": ["qemu-system-riscv32", "-machine", "virt", "-nographic", "-bios", "none", "-kernel"]

targets/riscv.json

@@ -8,6 +8,7 @@
 	"libc": "picolibc",
 	"cflags": [
 		"-Werror",
+		"-mno-relax",
 		"-fno-exceptions", "-fno-unwind-tables",
 		"-ffunction-sections", "-fdata-sections"
 	],