From 9f4459cee160b8bf7ca39b69d223035c5635bbd3 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Tue, 12 May 2020 20:45:58 +0200
Subject: [PATCH] arm: make FPU configuraton consistent

Eventually we might want to start using the FPU, but the easy option
right now is to simply disable it everywhere. Previously, it depended on
whether Clang was built as part of TinyGo or it was an external binary.
By setting the floating point mode explicitly, such inconsistencies are
avoided.

This commit creates a new cortex-m4 target which can be the central
place for setting FPU-related settings across all Cortex-M4 chips.
---
 builder/library.go        | 2 +-
 targets/atsamd51g19a.json | 4 +---
 targets/atsamd51j19a.json | 4 +---
 targets/atsamd51j20a.json | 4 +---
 targets/cortex-m4.json    | 8 ++++++++
 targets/nrf52.json        | 5 +----
 targets/nrf52840.json     | 5 +----
 targets/stm32f4disco.json | 4 +---
 8 files changed, 15 insertions(+), 21 deletions(-)
 create mode 100644 targets/cortex-m4.json

diff --git a/builder/library.go b/builder/library.go
index d85e4d36..7bb506c7 100644
--- a/builder/library.go
+++ b/builder/library.go
@@ -69,7 +69,7 @@ func (l *Library) Load(target string) (path string, err error) {
 	// Precalculate the flags to the compiler invocation.
 	args := append(l.cflags(), "-c", "-Oz", "-g", "-ffunction-sections", "-fdata-sections", "-Wno-macro-redefined", "--target="+target, "-fdebug-prefix-map="+dir+"="+remapDir)
 	if strings.HasPrefix(target, "arm") || strings.HasPrefix(target, "thumb") {
-		args = append(args, "-fshort-enums", "-fomit-frame-pointer")
+		args = append(args, "-fshort-enums", "-fomit-frame-pointer", "-mfloat-abi=soft")
 	}
 	if strings.HasPrefix(target, "riscv32-") {
 		args = append(args, "-march=rv32imac", "-mabi=ilp32", "-fforce-enable-int128")
diff --git a/targets/atsamd51g19a.json b/targets/atsamd51g19a.json
index 59e2cd58..c3ac8160 100644
--- a/targets/atsamd51g19a.json
+++ b/targets/atsamd51g19a.json
@@ -1,9 +1,7 @@
 {
-	"inherits": ["cortex-m"],
-	"llvm-target": "armv7em-none-eabi",
+	"inherits": ["cortex-m4"],
 	"build-tags": ["atsamd51g19", "atsamd51", "sam"],
 	"cflags": [
-		"--target=armv7em-none-eabi",
 		"-Qunused-arguments"
 	],
 	"linkerscript": "targets/atsamd51.ld",
diff --git a/targets/atsamd51j19a.json b/targets/atsamd51j19a.json
index 9ddde66f..1bd42a0a 100644
--- a/targets/atsamd51j19a.json
+++ b/targets/atsamd51j19a.json
@@ -1,9 +1,7 @@
 {
-	"inherits": ["cortex-m"],
-	"llvm-target": "armv7em-none-eabi",
+	"inherits": ["cortex-m4"],
 	"build-tags": ["atsamd51j19", "atsamd51", "sam"],
 	"cflags": [
-		"--target=armv7em-none-eabi",
 		"-Qunused-arguments"
 	],
 	"linkerscript": "targets/atsamd51.ld",
diff --git a/targets/atsamd51j20a.json b/targets/atsamd51j20a.json
index cd8b431c..2089b5d6 100644
--- a/targets/atsamd51j20a.json
+++ b/targets/atsamd51j20a.json
@@ -1,9 +1,7 @@
 {
-	"inherits": ["cortex-m"],
-	"llvm-target": "armv7em-none-eabi",
+	"inherits": ["cortex-m4"],
 	"build-tags": ["sam", "atsamd51", "atsamd51j20", "atsamd51j20a"],
 	"cflags": [
-		"--target=armv7em-none-eabi",
 		"-Qunused-arguments"
 	],
 	"linkerscript": "targets/atsamd51j20a.ld",
diff --git a/targets/cortex-m4.json b/targets/cortex-m4.json
new file mode 100644
index 00000000..1d5ce2b1
--- /dev/null
+++ b/targets/cortex-m4.json
@@ -0,0 +1,8 @@
+{
+	"inherits": ["cortex-m"],
+	"llvm-target": "armv7em-none-eabi",
+	"cflags": [
+		"--target=armv7em-none-eabi",
+		"-mfloat-abi=soft"
+	]
+}
diff --git a/targets/nrf52.json b/targets/nrf52.json
index d48c9d33..58f42c29 100644
--- a/targets/nrf52.json
+++ b/targets/nrf52.json
@@ -1,10 +1,7 @@
 {
-	"inherits": ["cortex-m"],
-	"llvm-target": "armv7em-none-eabi",
+	"inherits": ["cortex-m4"],
 	"build-tags": ["nrf52", "nrf"],
 	"cflags": [
-		"--target=armv7em-none-eabi",
-		"-mfloat-abi=soft",
 		"-Qunused-arguments",
 		"-DNRF52832_XXAA",
 		"-I{root}/lib/CMSIS/CMSIS/Include",
diff --git a/targets/nrf52840.json b/targets/nrf52840.json
index 2c2eff7c..4ab30a20 100644
--- a/targets/nrf52840.json
+++ b/targets/nrf52840.json
@@ -1,10 +1,7 @@
 {
-	"inherits": ["cortex-m"],
-	"llvm-target": "armv7em-none-eabi",
+	"inherits": ["cortex-m4"],
 	"build-tags": ["nrf52840", "nrf"],
 	"cflags": [
-		"--target=armv7em-none-eabi",
-		"-mfloat-abi=soft",
 		"-Qunused-arguments",
 		"-DNRF52840_XXAA",
 		"-I{root}/lib/CMSIS/CMSIS/Include",
diff --git a/targets/stm32f4disco.json b/targets/stm32f4disco.json
index c142ab23..889d7c51 100644
--- a/targets/stm32f4disco.json
+++ b/targets/stm32f4disco.json
@@ -1,9 +1,7 @@
 {
-  "inherits": ["cortex-m"],
-  "llvm-target": "armv7em-none-eabi",
+  "inherits": ["cortex-m4"],
   "build-tags": ["stm32f4disco", "stm32f407", "stm32"],
   "cflags": [
-    "--target=armv7em-none-eabi",
     "-Qunused-arguments"
   ],
   "linkerscript": "targets/stm32f407.ld",