Tier 1 support for hexagon-linux

[alexrp]

• Standard library support
• libc is available even when cross-compiling
• Stack traces work
• All behavior tests pass
• All standard library tests pass
• No disabled tests
• Enabled in CI (QEMU)

Open issues:

• Consider integrating Qualcomm's musl port for Hexagon #21588
• Re-enable native f16 lowering for Hexagon #22013

[alexrp]

Just noting that further progress on this port is basically blocked until LLVM 20 due to llvm/llvm-project#116798; we can't link anything larger than trivial freestanding programs due to it, including all module tests.

[androm3da]

Just noting that further progress on this port is basically blocked until LLVM 20 due to llvm/llvm-project#116798; we can't link anything larger than trivial freestanding programs due to it, including all module tests.

This has now been backported to 19.1.5 - sorry for the inconvenience. Let me know if you come across any other issues.

[alexrp]

This has now been backported to 19.1.5 - sorry for the inconvenience. Let me know if you come across any other issues.

Nice; I wasn't confident the backport would be accepted. Thanks!

[alexrp]

test-c-import, test-compiler-rt, and test-universal-libc now pass.

test-behavior fails with:

test-behavior
└─ run test behavior-hexagon-linux.4.19...6.11.5-none.2.28-hexagonv60-Debug
   └─ zig test Debug hexagon-linux-none failure
error: zig: /home/alexrp/Source/llvm-project/llvm/include/llvm/CodeGen/ValueTypes.h:307: llvm::MVT llvm::EVT::getSimpleVT() const: Assertion `isSimple() && "Expected a SimpleValueType!"' failed.

error: the following command terminated unexpectedly:
/home/alexrp/Source/ziglang/zig/zig-out/bin/zig test -ODebug -target hexagon-linux-none -mcpu baseline -Mroot=/home/alexrp/Source/ziglang/zig/test/behavior.zig --cache-dir /home/alexrp/Source/ziglang/zig/.zig-cache --global-cache-dir /home/alexrp/.cache/zig --name test -L /opt/llvm-19/lib -I /opt/llvm-19/include --zig-lib-dir /home/alexrp/Source/ziglang/zig/lib --listen=-

test-std fails with:

test-std
└─ run test std-hexagon-linux.4.19...6.11.5-none.2.28-hexagonv60-Debug
   └─ zig test Debug hexagon-linux-none failure
error: Call operand #1 has unhandled type v4i1
UNREACHABLE executed at /home/alexrp/Source/llvm-project/llvm/lib/CodeGen/CallingConvLower.cpp:137!

error: the following command terminated unexpectedly:
/home/alexrp/Source/ziglang/zig/zig-out/bin/zig test -ODebug -target hexagon-linux-none -mcpu baseline -Mroot=/home/alexrp/Source/ziglang/zig/lib/std/std.zig --cache-dir /home/alexrp/Source/ziglang/zig/.zig-cache --global-cache-dir /home/alexrp/.cache/zig --name test -L /opt/llvm-19/lib -I /opt/llvm-19/include --zig-lib-dir /home/alexrp/Source/ziglang/zig/lib --listen=-

We're probably exercising a lot of code paths in the Hexagon backend that Clang doesn't. 🙂

[alexrp]

• [Hexagon] Cannot handle call operand v8i1 llvm/llvm-project#59009
• [llvm][Hexagon] unable to allocate function argument crash in llvm::HexagonTargetLowering::LowerFormalArguments() llvm/llvm-project#118879
• [llvm][Hexagon] Expected a SimpleValueType crash with vectors of large integers llvm/llvm-project#118881