[llvm] [Github][libc] Add qemu-system-hexagon to the libc container (PR #219433)

[via llvm-commits]

https://github.com/quic-k updated https://github.com/llvm/llvm-project/pull/219433

>From 44b757d61be84eb359046e10d12a42554e595071 Mon Sep 17 00:00:00 2001
From: Kushal Pal <kushpal at qti.qualcomm.com>
Date: Fri, 28 Aug 2026 15:49:21 +0530
Subject: [PATCH] [Github][libc] Add qemu-system-hexagon to the libc container

Running the LLVM libc bare-metal hermetic tests for Hexagon requires a
Hexagon system emulator. This is not available as a distribution package,
and the machine model the tests use ("-M sim") currently only exists in
the Qualcomm fork of QEMU, so build just the hexagon-softmmu target from
source and pin to a tag from there.

The installed binary is smoke-tested before the source tree is removed.

This only makes the emulator available in the image. Enabling the Hexagon
libc tests in CI is a follow-up change.

Signed-off-by: Kushal Pal <kushpal at qti.qualcomm.com>
---
 .github/workflows/containers/libc/Dockerfile | 28 +++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/.github/workflows/containers/libc/Dockerfile b/.github/workflows/containers/libc/Dockerfile
index d2cb71435059a..b79da99176c14 100644
--- a/.github/workflows/containers/libc/Dockerfile
+++ b/.github/workflows/containers/libc/Dockerfile
@@ -1,6 +1,7 @@
 FROM docker.io/library/ubuntu:24.04
 
 # MPFR is required by some of the mathlib tests.
+# The last few packages are needed to build qemu-system-hexagon below.
 RUN apt-get update && \
     apt-get install -y \
     git \
@@ -36,7 +37,13 @@ RUN apt-get update && \
     gnupg \
     cmake \
     m4 \
-    linux-libc-dev && \
+    linux-libc-dev \
+    libglib2.0-dev \
+    libfdt-dev \
+    pkg-config \
+    python3-venv \
+    flex \
+    bison && \
     apt-get clean && \
     rm -rf /var/lib/apt/lists/*
 
@@ -56,6 +63,25 @@ RUN apt-get install -y llvm-23-tools && \
     ln -s -t /usr/bin $(dpkg -L llvm-23-tools | grep '^/usr/lib/llvm-23/bin/') && \
     ln -s /usr/lib/llvm-23/bin/llvm-link /usr/bin/llvm-link
 
+# Build qemu-system-hexagon, which is needed to run the LLVM libc bare-metal
+# hermetic tests for Hexagon. Hexagon system emulation is not available as a
+# distribution package, and the machine model used by the tests ("-M sim")
+# currently only exists in the Qualcomm fork, so build it from source and pin
+# to a tag from there. The dependencies it needs are installed above.
+RUN git clone --depth 1 --branch hexagon-sysemu-23-apr-2026 \
+    https://github.com/qualcomm/qemu.git qemu-hexagon && \
+    cd qemu-hexagon && \
+    ./configure \
+    --target-list=hexagon-softmmu \
+    --prefix=/opt/qemu-hexagon \
+    --disable-werror && \
+    ninja -C build install && \
+    /opt/qemu-hexagon/bin/qemu-system-hexagon -M help | grep -q '^sim ' && \
+    cd .. && \
+    rm -rf qemu-hexagon
+
+ENV PATH="/opt/qemu-hexagon/bin:${PATH}"
+
 # Install gmp and mpfr for cross compilation
 RUN wget https://ftp.gnu.org/gnu/gmp/gmp-6.3.0.tar.xz && \
     tar -xf gmp-6.3.0.tar.xz && \