all: compile and link using clang, where possible

11 files changed, 79 insertions, 68 deletions

diff --git a/targets/arduino.json b/targets/arduino.json
index 795a99564..20e592be9 100644
--- a/targets/arduino.json
+++ b/targets/arduino.json
@@ -2,14 +2,15 @@
 	"inherits": ["avr"],
 	"llvm-target": "avr-atmel-none",
 	"build-tags": ["arduino", "atmega328p", "atmega", "avr5"],
-	"pre-link-args": [
-		"-nostartfiles",
-		"-mmcu=avr5",
+	"cflags": [
+		"-mmcu=atmega328p"
+	],
+	"ldflags": [
 		"-Wl,--defsym=_bootloader_size=512",
 		"-Wl,--defsym=_stack_size=512",
-		"-T", "src/device/avr/atmega328p.ld",
-		"-T", "targets/avr.ld",
-		"-Wl,--gc-sections",
+		"-T", "src/device/avr/atmega328p.ld"
+	],
+	"extra-files": [
 		"targets/avr.S",
 		"src/device/avr/atmega328p.s"
 	],
diff --git a/targets/arm.ld b/targets/arm.ld
index 2788fddd2..c964331da 100644
--- a/targets/arm.ld
+++ b/targets/arm.ld
@@ -1,4 +1,7 @@
 
+/* Unused, but here to silence a linker warning. */
+ENTRY(Reset_Handler)
+
 /* define output sections */
 SECTIONS
 {
diff --git a/targets/avr.json b/targets/avr.json
index debb54786..abe486ec3 100644
--- a/targets/avr.json
+++ b/targets/avr.json
@@ -1,5 +1,10 @@
 {
 	"build-tags": ["avr", "js", "wasm"],
+	"compiler": "avr-gcc",
 	"linker": "avr-gcc",
-	"objcopy": "avr-objcopy"
+	"objcopy": "avr-objcopy",
+	"ldflags": [
+		"-T", "targets/avr.ld",
+		"-Wl,--gc-sections"
+	]
 }
diff --git a/targets/bluepill.json b/targets/bluepill.json
index 3c086ec69..ef2c915ac 100644
--- a/targets/bluepill.json
+++ b/targets/bluepill.json
@@ -2,16 +2,14 @@
 	"inherits": ["cortex-m"],
 	"llvm-target": "armv7m-none-eabi",
 	"build-tags": ["bluepill", "stm32f103xx", "stm32"],
-	"pre-link-args": [
-		"-nostdlib",
-		"-nostartfiles",
-		"-mcpu=cortex-m3",
-		"-mthumb",
-		"-T", "targets/stm32.ld",
-		"-Wl,--gc-sections",
-		"-fno-exceptions", "-fno-unwind-tables",
-		"-ffunction-sections", "-fdata-sections",
-		"-Os",
+	"cflags": [
+		"--target=armv7m-none-eabi",
+		"-Qunused-arguments"
+	],
+	"ldflags": [
+		"-T", "targets/stm32.ld"
+	],
+	"extra-files": [
 		"src/device/stm32/stm32f103xx.s"
 	],
 	"flash": "openocd -f interface/stlink-v2.cfg -f target/stm32f1x.cfg -c 'program {hex} reset exit'"
diff --git a/targets/cortex-m.json b/targets/cortex-m.json
index 71d354f45..b373ef9b4 100644
--- a/targets/cortex-m.json
+++ b/targets/cortex-m.json
@@ -1,7 +1,18 @@
 {
 	"build-tags": ["tinygo.arm", "js", "wasm"],
-	"linker": "arm-none-eabi-gcc",
+	"compiler": "clang-7",
+	"linker": "arm-none-eabi-ld",
 	"rtlib": "compiler-rt",
+	"cflags": [
+		"-Oz",
+		"-mthumb",
+		"-fshort-enums",
+		"-fno-exceptions", "-fno-unwind-tables",
+		"-ffunction-sections", "-fdata-sections"
+	],
+	"ldflags": [
+		"--gc-sections"
+	],
 	"objcopy": "arm-none-eabi-objcopy",
 	"gdb": "arm-none-eabi-gdb"
 }
diff --git a/targets/cortex-m.s b/targets/cortex-m.s
index 62ed28ef6..595ff56f8 100644
--- a/targets/cortex-m.s
+++ b/targets/cortex-m.s
@@ -26,7 +26,7 @@ Default_Handler:
     .set   \handler, Default_Handler
 .endm
 
-.section .isr_vector
+.section .isr_vector, "a", %progbits
 .global  __isr_vector
     // Interrupt vector as defined by Cortex-M, starting with the stack top.
     // On reset, SP is initialized with *0x0 and PC is loaded with *0x4, loading
diff --git a/targets/digispark.json b/targets/digispark.json
index 02d9b87e4..6c198f4f5 100644
--- a/targets/digispark.json
+++ b/targets/digispark.json
@@ -2,14 +2,15 @@
 	"inherits": ["avr"],
 	"llvm-target": "avr-atmel-none",
 	"build-tags": ["digispark", "attiny85", "attiny", "avr2", "avr25"],
-	"pre-link-args": [
-		"-nostartfiles",
-		"-mmcu=attiny85",
+	"cflags": [
+		"-mmcu=attiny85"
+	],
+	"ldflags": [
 		"-Wl,--defsym=_bootloader_size=2180",
 		"-Wl,--defsym=_stack_size=128",
-		"-T", "src/device/avr/attiny85.ld",
-		"-T", "targets/avr.ld",
-		"-Wl,--gc-sections",
+		"-T", "src/device/avr/attiny85.ld"
+	],
+	"extra-files": [
 		"targets/avr.S",
 		"src/device/avr/attiny85.s"
 	],
diff --git a/targets/nrf51.json b/targets/nrf51.json
index 68c6b14f3..f37db3e92 100644
--- a/targets/nrf51.json
+++ b/targets/nrf51.json
@@ -2,18 +2,16 @@
 	"inherits": ["cortex-m"],
 	"llvm-target": "armv6m-none-eabi",
 	"build-tags": ["nrf51822", "nrf51", "nrf"],
-	"pre-link-args": [
-		"-nostdlib",
-		"-nostartfiles",
-		"-mcpu=cortex-m0",
-		"-mthumb",
-		"-T", "targets/nrf51.ld",
-		"-Wl,--gc-sections",
-		"-fno-exceptions", "-fno-unwind-tables",
-		"-ffunction-sections", "-fdata-sections",
-		"-Os",
+	"cflags": [
+		"--target=armv6m-none-eabi",
+		"-Qunused-arguments",
 		"-DNRF51",
-		"-Ilib/CMSIS/CMSIS/Include",
+		"-Ilib/CMSIS/CMSIS/Include"
+	],
+	"ldflags": [
+		"-T", "targets/nrf51.ld"
+	],
+	"extra-files": [
 		"lib/nrfx/mdk/system_nrf51.c",
 		"src/device/nrf/nrf51.s"
 	]
diff --git a/targets/nrf52.json b/targets/nrf52.json
index 53ff2a47e..6eeaf651a 100644
--- a/targets/nrf52.json
+++ b/targets/nrf52.json
@@ -2,18 +2,16 @@
 	"inherits": ["cortex-m"],
 	"llvm-target": "armv7em-none-eabi",
 	"build-tags": ["nrf52", "nrf"],
-	"pre-link-args": [
-		"-nostdlib",
-		"-nostartfiles",
-		"-mcpu=cortex-m4",
-		"-mthumb",
-		"-T", "targets/nrf52.ld",
-		"-Wl,--gc-sections",
-		"-fno-exceptions", "-fno-unwind-tables",
-		"-ffunction-sections", "-fdata-sections",
-		"-Os",
+	"cflags": [
+		"--target=armv7em-none-eabi",
+		"-Qunused-arguments",
 		"-DNRF52832_XXAA",
-		"-Ilib/CMSIS/CMSIS/Include",
+		"-Ilib/CMSIS/CMSIS/Include"
+	],
+	"ldflags": [
+		"-T", "targets/nrf52.ld"
+	],
+	"extra-files": [
 		"lib/nrfx/mdk/system_nrf52.c",
 		"src/device/nrf/nrf52.s"
 	]
diff --git a/targets/nrf52840.json b/targets/nrf52840.json
index 8346735c2..d49a1f0a2 100644
--- a/targets/nrf52840.json
+++ b/targets/nrf52840.json
@@ -2,18 +2,16 @@
 	"inherits": ["cortex-m"],
 	"llvm-target": "armv7em-none-eabi",
 	"build-tags": ["nrf52840", "nrf"],
-	"pre-link-args": [
-		"-nostdlib",
-		"-nostartfiles",
-		"-mcpu=cortex-m4",
-		"-mthumb",
-		"-T", "targets/nrf52840.ld",
-		"-Wl,--gc-sections",
-		"-fno-exceptions", "-fno-unwind-tables",
-		"-ffunction-sections", "-fdata-sections",
-		"-Os",
+	"cflags": [
+		"--target=armv7em-none-eabi",
+		"-Qunused-arguments",
 		"-DNRF52840_XXAA",
-		"-Ilib/CMSIS/CMSIS/Include",
+		"-Ilib/CMSIS/CMSIS/Include"
+	],
+	"ldflags": [
+		"-T", "targets/nrf52840.ld"
+	],
+	"extra-files": [
 		"lib/nrfx/mdk/system_nrf52840.c",
 		"src/device/nrf/nrf52840.s"
 	]
diff --git a/targets/qemu.json b/targets/qemu.json
index 7cc23da8f..929fb1e85 100644
--- a/targets/qemu.json
+++ b/targets/qemu.json
@@ -2,16 +2,14 @@
 	"inherits": ["cortex-m"],
 	"llvm-target": "armv7m-none-eabi",
 	"build-tags": ["qemu", "lm3s6965"],
-	"pre-link-args": [
-		"-nostdlib",
-		"-nostartfiles",
-		"-mcpu=cortex-m0",
-		"-mthumb",
-		"-T", "targets/lm3s6965.ld",
-		"-Wl,--gc-sections",
-		"-fno-exceptions", "-fno-unwind-tables",
-		"-ffunction-sections", "-fdata-sections",
-		"-Os",
+	"cflags": [
+		"--target=armv7m-none-eabi",
+		"-Qunused-arguments"
+	],
+	"ldflags": [
+		"-T", "targets/lm3s6965.ld"
+	],
+	"extra-files": [
 		"targets/cortex-m.s"
 	],
 	"emulator": ["qemu-system-arm", "-machine", "lm3s6965evb", "-semihosting", "-nographic", "-kernel"]