From d931ab843e03bcde94676c6111a75c9f86561b4b Mon Sep 17 00:00:00 2001
From: Anthony Shoumikhin <anthony@shoumikh.in>
Date: Thu, 22 Oct 2026 23:16:36 -0700
Subject: [PATCH] Drop the unused LLVM download from setup-qnn-deps.sh

setup-qnn-deps.sh calls setup_libcpp, which downloads a 575 MB LLVM
release from GitHub. A connection reset during that download fails QNN
CI jobs, but nothing uses what it installs:

- Every workflow runs setup-qnn-deps.sh with bash, so the paths
  setup_libcpp exports are gone when the script exits, and nothing
  else reads its install folder.
- Its copy step does not even pick up libc++. The libc++ libraries sit
  in a subfolder its glob does not reach.
- The QNN backend test jobs never call it and pass. The CI image gets
  libc++ from the system package.

Remove the call and the function, which nothing else uses. This fixes
the flaky download and saves about half a minute per QNN job.
---
 .ci/scripts/setup-qnn-deps.sh                |  1 -
 backends/qualcomm/scripts/install_qnn_sdk.sh | 65 --------------------
 2 files changed, 66 deletions(-)

diff --git a/.ci/scripts/setup-qnn-deps.sh b/.ci/scripts/setup-qnn-deps.sh
index 8b1afecd47a..ca555f507f3 100644
--- a/.ci/scripts/setup-qnn-deps.sh
+++ b/.ci/scripts/setup-qnn-deps.sh
@@ -9,7 +9,6 @@ set -ex
 
 source "$(dirname "${BASH_SOURCE[0]}")/../../backends/qualcomm/scripts/install_qnn_sdk.sh"
 
-setup_libcpp 12
 setup_android_ndk
 install_qnn
 pip install -r backends/qualcomm/requirements.txt
\ No newline at end of file
diff --git a/backends/qualcomm/scripts/install_qnn_sdk.sh b/backends/qualcomm/scripts/install_qnn_sdk.sh
index a7a9e3ba5e5..0d5516bf567 100644
--- a/backends/qualcomm/scripts/install_qnn_sdk.sh
+++ b/backends/qualcomm/scripts/install_qnn_sdk.sh
@@ -203,68 +203,3 @@ install_hexagon_sdk() {
   echo "Set HEXAGON_SDK_ROOT=${HEXAGON_SDK_ROOT}"
   echo "Set HEXAGON_TOOLS_ROOT=${HEXAGON_TOOLS_ROOT}"
 }
-
-setup_libcpp() {
-  clang_version=$1
-  LLVM_VERSION="14.0.0"
-  INSTALL_DIR="/tmp/libcxx-${LLVM_VERSION}"
-
-  # Check if we already have a local installation
-  if [ -d "${INSTALL_DIR}/include" ] && [ -d "${INSTALL_DIR}/lib" ]; then
-    echo "Local libc++ already installed at ${INSTALL_DIR} - skipping"
-    # Set environment variables
-    export CPLUS_INCLUDE_PATH="${INSTALL_DIR}/include:$CPLUS_INCLUDE_PATH"
-    export LD_LIBRARY_PATH="${INSTALL_DIR}/lib:$LD_LIBRARY_PATH"
-    export LIBRARY_PATH="${INSTALL_DIR}/lib:$LIBRARY_PATH"
-    return
-  fi
-
-  echo "Installing libc++ manually to ${INSTALL_DIR}"
-
-  # Create temporary directory
-  TEMP_DIR=$(mktemp -d)
-  # Ensure cleanup on exit or return
-  trap 'rm -rf "$TEMP_DIR"' RETURN
-
-  pushd "${TEMP_DIR}" >/dev/null
-
-  BASE_NAME="clang+llvm-${LLVM_VERSION}-x86_64-linux-gnu-ubuntu-18.04"
-  LLVM_URL="https://github.com/llvm/llvm-project/releases/download/llvmorg-${LLVM_VERSION}/${BASE_NAME}.tar.xz"
-
-  echo "Downloading LLVM from ${LLVM_URL}"
-  curl --retry 3 -fLO "${LLVM_URL}" || {
-      echo "Error: Failed to download LLVM"
-      exit 1
-  }
-
-  echo "Extracting ${BASE_NAME}.tar.xz"
-  tar -xf "${BASE_NAME}.tar.xz" || {
-      echo "Error: Failed to extract LLVM archive"
-      exit 1
-  }
-
-  # Create installation directory
-  mkdir -p "${INSTALL_DIR}/include"
-  mkdir -p "${INSTALL_DIR}/lib"
-
-  # Copy libc++ headers and libraries
-  cp -r "${BASE_NAME}/include/c++/v1/"* "${INSTALL_DIR}/include/"
-  cp -r "${BASE_NAME}/lib/"*.so* "${INSTALL_DIR}/lib/"
-
-  popd >/dev/null
-
-  # Create necessary symlinks locally
-  pushd "${INSTALL_DIR}/lib" >/dev/null
-  ln -sf libc++.so.1.0 libc++.so.1
-  ln -sf libc++.so.1 libc++.so
-  ln -sf libc++abi.so.1.0 libc++abi.so.1
-  ln -sf libc++abi.so.1 libc++abi.so
-  popd >/dev/null
-
-  # Set environment variables
-  export CPLUS_INCLUDE_PATH="${INSTALL_DIR}/include:${CPLUS_INCLUDE_PATH:-}"
-  export LD_LIBRARY_PATH="${INSTALL_DIR}/lib:${LD_LIBRARY_PATH:-}"
-  export LIBRARY_PATH="${INSTALL_DIR}/lib:${LIBRARY_PATH:-}"
-
-  echo "libc++ installed to ${INSTALL_DIR}"
-}