Commit aff2e47821aaad5cac74ed8a3cac2e72283b594b | zig

author	vegecode <justin.b.alexander1@gmail.com> 2019-04-07 22:17:21-05:00
committer	Andrew Kelley <andrew@ziglang.org> 2019-04-10 12:35:16-04:00
log	aff2e47821aaad5cac74ed8a3cac2e72283b594b
tree	a34d36b0b6a4e628a5be0bb883e03607bf877194
parent	dea1027f9799e6ce0f7f2594c6b555d9675c281a

compiler-rt: correct use_thumb_1 flag

The flag is for generating correct arm-thumb interwork veneers in the
assembly code __aeabi_{memcpy,memset,etc} functions.

Armv6m only does thumb code generation regardless of whether arm or
thumb is selected and armv6t2 uses the newer thumb 2 set. All other
versions that zig supports pre-armv7 need the veneers and hence the
flag. Armv5 is actually armv5t.

Relevant code from clang/lib/Basic/Targets/Arm.cpp

```c
bool ARMTargetInfo::isThumb() const {
  return ArchISA == llvm::ARM::ISAKind::THUMB;
  }

bool ARMTargetInfo::supportsThumb() const {
  return CPUAttr.count('T') || ArchVersion >= 6;
}

bool ARMTargetInfo::supportsThumb2() const {
  return CPUAttr.equals("6T2") ||
    (ArchVersion >= 7 && !CPUAttr.equals("8M_BASE"));
}
```

Also see

http://www.llvm.org/svn/llvm-project/llvm/trunk/lib/Target/ARM/ARM.td

1 files changed, 69 insertions(+), 8 deletions(-)

std
- special
  - compiler_rt.zig

std/special/compiler_rt.zig+69-8

...	@@ -253,14 +253,75 @@ const is_arm_arch = switch (builtin.arch) {	...	@@ -253,14 +253,75 @@ const is_arm_arch = switch (builtin.arch) {
253		253
254	const is_arm_32 = is_arm_arch and !is_arm_64;	254	const is_arm_32 = is_arm_arch and !is_arm_64;
255		255
256	const use_thumb_1 = is_arm_32 and switch (builtin.arch.arm) {	256	const use_thumb_1 = usesThumb1(builtin.arch);
257	builtin.Arch.Arm32.v6,	257
258	builtin.Arch.Arm32.v6m,	258	fn usesThumb1(arch: builtin.Arch) bool {
259	builtin.Arch.Arm32.v6k,	259	return switch (arch) {
260	builtin.Arch.Arm32.v6t2,	260	.arm => switch (arch.arm) {
261	=> true,	261	.v6m => true,
262	else => false,	262	else => false,
263	};	263	},
		264	.armeb => switch (arch.armeb) {
		265	.v6m => true,
		266	else => false,
		267	},
		268	.thumb => switch (arch.thumb) {
		269	.v5,
		270	.v5te,
		271	.v4t,
		272	.v6,
		273	.v6m,
		274	.v6k,
		275	=> true,
		276	else => false,
		277	},
		278	.thumbeb => switch (arch.thumbeb) {
		279	.v5,
		280	.v5te,
		281	.v4t,
		282	.v6,
		283	.v6m,
		284	.v6k,
		285	=> true,
		286	else => false,
		287	},
		288	else => false,
		289	};
		290	}
		291
		292	test "usesThumb1" {
		293	testing.expect(usesThumb1(builtin.Arch{ .arm = .v6m }));
		294	testing.expect(!usesThumb1(builtin.Arch{ .arm = .v5 }));
		295	//etc.
		296
		297	testing.expect(usesThumb1(builtin.Arch{ .armeb = .v6m }));
		298	testing.expect(!usesThumb1(builtin.Arch{ .armeb = .v5 }));
		299	//etc.
		300
		301	testing.expect(usesThumb1(builtin.Arch{ .thumb = .v5 }));
		302	testing.expect(usesThumb1(builtin.Arch{ .thumb = .v5te }));
		303	testing.expect(usesThumb1(builtin.Arch{ .thumb = .v4t }));
		304	testing.expect(usesThumb1(builtin.Arch{ .thumb = .v6 }));
		305	testing.expect(usesThumb1(builtin.Arch{ .thumb = .v6k }));
		306	testing.expect(usesThumb1(builtin.Arch{ .thumb = .v6m }));
		307	testing.expect(!usesThumb1(builtin.Arch{ .thumb = .v6t2 }));
		308	//etc.
		309
		310	testing.expect(usesThumb1(builtin.Arch{ .thumbeb = .v5 }));
		311	testing.expect(usesThumb1(builtin.Arch{ .thumbeb = .v5te }));
		312	testing.expect(usesThumb1(builtin.Arch{ .thumbeb = .v4t }));
		313	testing.expect(usesThumb1(builtin.Arch{ .thumbeb = .v6 }));
		314	testing.expect(usesThumb1(builtin.Arch{ .thumbeb = .v6k }));
		315	testing.expect(usesThumb1(builtin.Arch{ .thumbeb = .v6m }));
		316	testing.expect(!usesThumb1(builtin.Arch{ .thumbeb = .v6t2 }));
		317	//etc.
		318
		319	testing.expect(!usesThumb1(builtin.Arch{ .aarch64 = .v8 }));
		320	testing.expect(!usesThumb1(builtin.Arch{ .aarch64_be = .v8 }));
		321	testing.expect(!usesThumb1(builtin.Arch.x86_64));
		322	testing.expect(!usesThumb1(builtin.Arch.riscv32));
		323	//etc.
		324	}
264		325
265	nakedcc fn __aeabi_uidivmod() void {	326	nakedcc fn __aeabi_uidivmod() void {
266	@setRuntimeSafety(false);	327	@setRuntimeSafety(false);