uClibc and -checkaction=C

[sarneaud]

uClibc's assert() implementation uses a 4-parameter __assert() function, like the __assert_fail() function in other libcs.

Currently ldc2 doesn't recognise uClibc and falls back to generating code for a 3-parameter __assert(). I don't see an easy fix because LLVM's target triples don't seem to support uClibc.

[kinke]

I don't see an easy fix because LLVM's target triples don't seem to support uClibc.

We have this as workaround for that:

ldc/driver/main.cpp

Lines 536 to 545 in 7474c19

	void fixupUClibcEnv() {
	llvm::Triple triple(mTargetTriple);
	if (triple.getEnvironmentName().find("uclibc") != 0)
	return;
	std::string envName = triple.getEnvironmentName();
	envName.replace(0, 6, "gnu");
	triple.setEnvironmentName(envName);
	mTargetTriple = triple.normalize();
	isUClibc = true;
	}

This isUClibc is currently only used to set the predefined version CRuntime_UClibc. We'd need to adapt this too:

ldc/gen/runtime.cpp

Lines 378 to 390 in 5e5ce19

	static std::vector<PotentiallyLazyType> getCAssertFunctionParamTypes() {
	const auto voidPtr = Type::tvoidptr;
	const auto uint = Type::tuns32;
	if (global.params.targetTriple->isOSDarwin() ||
	global.params.targetTriple->isOSSolaris() || isMusl()) {
	return {voidPtr, voidPtr, uint, voidPtr};
	}
	if (global.params.targetTriple->getEnvironment() == llvm::Triple::Android) {
	return {voidPtr, uint, voidPtr};
	}
	return {voidPtr, voidPtr, uint};
	}

[rracariu]

uClibc will work at least ARM and MIPS were tested to some extent, see the status issues: #2995 and #2810 - MIPS still has issues with ABI compatibility but this is not related to uClibc.

To enable uClibc support the triple looks like armv6-hardfloat-linux-uclibceabi or mipsel-unknown-linux-uclibc

[sarneaud]

@rracariu Thanks, but this is specifically a problem with -checkaction=C and uClibc, not uClibc support in general.

[rracariu]

@sarneaud OK, got it. Then exposing isUClibc outside main.cpp should work.
Maybe have a helper function similar to isMusl()