Preserve device debug info for gdb-oneapi (#1004)

llvm-patches/llvm/0007-preserve-device-debug-info.patch

@@ -0,0 +1,70 @@
+From db7c9f28fff802bd9f4165a344c3b5ef5f6973a2 Mon Sep 17 00:00:00 2001
+From: chipStar <chipstar@chip.spv>
+Date: Sat, 18 Jul 2026 14:18:22 +0300
+Subject: [PATCH] Preserve device debug info for gdb-oneapi
+
+HIPSPVToolChain::adjustDebugInfoKind() unconditionally forced NoDebugInfo,
+so -g/-O0 produced device SPIR-V with no debug metadata at all. The stated
+reason (SPIRV-LLVM-Translator aborting on DW_OP_LLVM_convert) no longer
+applies: the translator now lowers it to SPIRVDebug::Convert.
+
+Stop clobbering the requested debug level, and when -g is given emit the
+NonSemantic.Shader.DebugInfo form (--spirv-debug-info-version=
+nonsemantic-shader-200 + SPV_KHR_non_semantic_info) that Intel's IGC and
+gdb-oneapi consume to resolve source lines and locals in device code.
+
+Refs: CHIP-SPV/chipStar#1004
+---
+ clang/lib/Driver/ToolChains/HIPSPV.cpp | 34 +++++++++++++++++++++-----
+ 1 file changed, 28 insertions(+), 6 deletions(-)
+
+diff --git a/clang/lib/Driver/ToolChains/HIPSPV.cpp b/clang/lib/Driver/ToolChains/HIPSPV.cpp
+index 4cde8f9..58892d6 100644
+--- a/clang/lib/Driver/ToolChains/HIPSPV.cpp
++++ b/clang/lib/Driver/ToolChains/HIPSPV.cpp
+@@ -93,8 +93,23 @@ void HIPSPV::Linker::constructLinkAndEmitSpirvCommand(
+   // We need 1.2 when using warp-level primitivies via sub group extensions.
+   // Strictly put we'd need 1.3 for the standard non-extension shuffle
+   // operations, but it's not supported by any target yet.
+-  llvm::opt::ArgStringList TrArgs{"--spirv-max-version=1.2",
+-                                  "--spirv-ext=-all,+SPV_INTEL_function_pointers,+SPV_INTEL_subgroups,+SPV_EXT_shader_atomic_float_add"};
++  std::string SpirvExts =
++      "--spirv-ext=-all,+SPV_INTEL_function_pointers,+SPV_INTEL_subgroups,"
++      "+SPV_EXT_shader_atomic_float_add";
++  llvm::opt::ArgStringList TrArgs{"--spirv-max-version=1.2"};
++  // When the user requests debug info (-g, but not -g0), preserve it into the
++  // SPIR-V in the NonSemantic.Shader.DebugInfo form. Intel's IGC and gdb-oneapi
++  // consume this to map device code back to source lines and local variables;
++  // the translator's default OpenCL.DebugInfo.100 form is not sufficient for
++  // that. Emitting the NonSemantic debug instructions requires the
++  // SPV_KHR_non_semantic_info extension, so it is only enabled here on demand
++  // to keep the default (non-debug) SPIR-V output unchanged.
++  if (const Arg *A = Args.getLastArg(options::OPT_g_Group);
++      A && !A->getOption().matches(options::OPT_g0)) {
++    SpirvExts += ",+SPV_KHR_non_semantic_info";
++    TrArgs.push_back("--spirv-debug-info-version=nonsemantic-shader-200");
++  }
++  TrArgs.push_back(Args.MakeArgString(SpirvExts));
+   InputInfo TrInput = InputInfo(types::TY_LLVM_BC, TempFile, "");
+   SPIRV::constructTranslateCommand(C, *this, JA, Output, TrInput, TrArgs);
+ }
+@@ -283,8 +298,15 @@ VersionTuple HIPSPVToolChain::computeMSVCVersion(const Driver *D,
+ void HIPSPVToolChain::adjustDebugInfoKind(
+     llvm::codegenoptions::DebugInfoKind &DebugInfoKind,
+     const llvm::opt::ArgList &Args) const {
+-  // Debug info generation is disabled for SPIRV-LLVM-Translator
+-  // which currently aborts on the presence of DW_OP_LLVM_convert.
+-  // TODO: Enable debug info when the SPIR-V backend arrives.
+-  DebugInfoKind = llvm::codegenoptions::NoDebugInfo;
++  // Historically device debug info was force-disabled here because the
++  // SPIRV-LLVM-Translator aborted on DW_OP_LLVM_convert debug expressions.
++  // The translator now lowers that operation (SPIRVDebug::Convert), so honor
++  // the debug level the user requested (e.g. via -g) and let it flow into the
++  // emitted SPIR-V. constructLinkAndEmitSpirvCommand() additionally enables the
++  // NonSemantic.Shader.DebugInfo form at translation time so that Intel's IGC
++  // and gdb-oneapi can consume it. Leaving DebugInfoKind untouched keeps the
++  // default (no -g) behavior unchanged, since the driver defaults it to
++  // NoDebugInfo.
++  (void)DebugInfoKind;
++  (void)Args;
+ }