Jou on embedded

[Akuli]

From DMs with @Moosems:

This will probably require:

• changes to compiler (supporting different architectures, in LLVM and when linking)
• changes to the language (if WINDOWS: doesn't really make sense on embedded)
• documentation

[Moosems]

A special embedded api for pinout would likely be necessary as well

[Moosems]

How does target compilation work right now?

[Akuli]

Very much hard-coded / always using whatever system the compiler is running on:

jou/compiler/target.jou

Lines 25 to 49 in 2b33658

	@public
	def init_target() -> None:
	LLVMInitializeX86TargetInfo()
	LLVMInitializeX86Target()
	LLVMInitializeX86TargetMC()
	LLVMInitializeX86AsmParser()
	LLVMInitializeX86AsmPrinter()
	if MACOS:
	# Support the new M1 macs. This will enable the target also on x86_64
	# macs, but it doesn't matter.
	LLVMInitializeAArch64TargetInfo()
	LLVMInitializeAArch64Target()
	LLVMInitializeAArch64TargetMC()
	LLVMInitializeAArch64AsmParser()
	LLVMInitializeAArch64AsmPrinter()
	if WINDOWS:
	# LLVM's default is x86_64-pc-windows-msvc
	target.triple = "x86_64-pc-windows-gnu"
	else:
	triple = LLVMGetDefaultTargetTriple()
	assert strlen(triple) < sizeof target.triple
	strcpy(target.triple, triple)
	LLVMDisposeMessage(triple)

[Akuli]

Another problem is that 64-bitness is hard-coded into various places. C's size_t type is 32-bit or 64-bit depending on the platform. Jou assumes it is 64-bit.

For example, consider the strlen() function:

In Jou, it returns long, and Jou's long is always 64 bit:

jou/stdlib/str.jou

Lines 25 to 27 in 2b33658

	# Calculate the length of a string in bytes. Note that strlen("ö") == 2, for example.
	@public
	declare strlen(s: byte*) -> long

See also #304.