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 d85e4d365..7bb506c76 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 59e2cd58c..c3ac81608 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 9ddde66fe..1bd42a0ad 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 cd8b431cb..2089b5d6e 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 000000000..1d5ce2b19
--- /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 d48c9d33c..58f42c29e 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 2c2eff7ca..4ab30a208 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 c142ab23b..889d7c513 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",