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.

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"
 	],