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[DirectX][HLSL] Add /Qsource_in_debug_module to llc and Clang DXC driver #157

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[DirectX][HLSL] Add /Qsource_in_debug_module to llc and Clang DXC driver #157

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5 changes: 5 additions & 0 deletions clang/include/clang/Options/Options.td
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Original file line number Diff line number Diff line change
Expand Up @@ -9624,6 +9624,11 @@ def dxc_Fc : DXCJoinedOrSeparate<"Fc">,
HelpText<"Output assembly listing file">;
def dxc_Frs : DXCJoinedOrSeparate<"Frs">,
HelpText<"Output additional root signature object file">;
def dxc_source_in_debug_module
: Option<["/", "-"], "Qsource_in_debug_module", KIND_FLAG>,
Group<dxc_Group>,
Visibility<[DXCOption]>,
HelpText<"Embed source code into debug module on DirectX target">;
Comment on lines +9627 to +9631
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@kuilpd kuilpd Jun 2, 2026

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You can shorten this by using class DXCFlag like other flags do.

def dxil_validator_version : Option<["/", "-"], "validator-version", KIND_SEPARATE>,
Group<dxc_Group>, Flags<[HelpHidden]>,
Visibility<[DXCOption, ClangOption, CC1Option]>,
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5 changes: 5 additions & 0 deletions clang/lib/Driver/ToolChains/Clang.cpp
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Expand Up @@ -3832,6 +3832,11 @@ static void RenderHLSLOptions(const ArgList &Args, ArgStringList &CmdArgs,
if (!Args.hasArg(options::OPT_dxc_no_stdinc) &&
!Args.hasArg(options::OPT_nostdinc))
CmdArgs.push_back("-finclude-default-header");

if (Args.hasArg(options::OPT_dxc_source_in_debug_module)) {
CmdArgs.push_back("-mllvm");
CmdArgs.push_back("--dx-source-in-debug-module");
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@kuilpd kuilpd Jun 2, 2026

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Should we use a single dash for all llc options, just for the sake of consistency? I think most of the options are used like that.

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@dzhidzhoev dzhidzhoev Jun 2, 2026 •
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Should we use a single dash for all llc options, just for the sake of consistency?

AFAIK most of llc options (which are rather target-specific or pass-specific) use double dash (that's what I see in llc --help output):

PS D:\llvm\build\native> bin\llc --help | grep -v -- '--' | grep -c '\-\S' (estimate the number of lines with single dash options)
32
PS D:\llvm\build\native> bin\llc --help | grep -c '\--'
219

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@kuilpd kuilpd Jun 2, 2026

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Hm, I was judging by how they are usually forwarded in Clang.cpp, no idea why is it like that.

}
}

static void RenderOpenACCOptions(const Driver &D, const ArgList &Args,
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6 changes: 6 additions & 0 deletions clang/test/Driver/dxc_source_in_debug_module.hlsl
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@@ -0,0 +1,6 @@
// RUN: %clang_dxc -Tlib_6_7 -### /Zi /Qsource_in_debug_module %s 2>&1 | FileCheck %s
// RUN: %clang_dxc -Tlib_6_7 -### /Zi -Qsource_in_debug_module %s 2>&1 | FileCheck %s
// RUN: %clang_dxc -Tlib_6_7 -### /Zi %s 2>&1 | FileCheck %s --check-prefix=NOFLAG

// CHECK: "-mllvm" "--dx-source-in-debug-module"
// NOFLAG-NOT: --dx-source-in-debug-module
11 changes: 7 additions & 4 deletions llvm/lib/Target/DirectX/DXILTranslateMetadata.cpp
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Expand Up @@ -514,15 +514,18 @@ static void cleanModuleFlags(Module &M) {
M.addModuleFlag(Flag.Behavior, Flag.Key->getString(), Flag.Val);
}

using GlobalMDList = std::array<StringLiteral, 7>;
using GlobalMDList = std::array<StringLiteral, 11>;

// The following are compatible with DXIL but not emit with clang, they can
// be added when applicable:
// dx.typeAnnotations, dx.viewIDState, dx.dxrPayloadAnnotations
static GlobalMDList CompatibleNamedModuleMDs = {
"llvm.ident", "llvm.module.flags", "dx.resources", "dx.valver",
"dx.shaderModel", "dx.version", "dx.entryPoints",
};
"llvm.ident", "llvm.module.flags",
"dx.resources", "dx.valver",
"dx.shaderModel", "dx.version",
"dx.entryPoints", "dx.source.contents",
"dx.source.defines", "dx.source.mainFileName",
"dx.source.args"};

static void translateGlobalMetadata(Module &M, DXILResourceMap &DRM,
DXILResourceTypeMap &DRTM,
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26 changes: 26 additions & 0 deletions llvm/lib/Target/DirectX/DXILWriter/DXILWriterPass.cpp
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Expand Up @@ -28,11 +28,17 @@
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/Alignment.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"

using namespace llvm;
using namespace llvm::dxil;

static cl::opt<bool> SourceInDebugModule(
"dx-source-in-debug-module",
cl::desc("Embed source code into debug module on DirectX target"),
cl::init(false));

namespace {
class WriteDXILPass : public llvm::ModulePass {
raw_ostream &OS; // raw_ostream to print on
Expand Down Expand Up @@ -138,6 +144,16 @@ static void removeLifetimeIntrinsics(Module &M) {
}
}

static void replaceNamedMetadataArray(Module &M, StringRef Name,
ArrayRef<Metadata *> NewOps) {
NamedMDNode *NMD = M.getNamedMetadata(Name);
if (!NMD)
return;
NMD->eraseFromParent();
M.getOrInsertNamedMetadata(Name)->addOperand(
MDTuple::get(M.getContext(), NewOps));
}

class EmbedDXILPass : public llvm::ModulePass {
public:
static char ID; // Pass identification, replacement for typeid
Expand All @@ -155,6 +171,16 @@ class EmbedDXILPass : public llvm::ModulePass {
// fail the Module Verifier if performed in an earlier pass
legalizeLifetimeIntrinsics(M);

// Replace dx.source metadata nodes with stubs.
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@kuilpd kuilpd Jun 2, 2026

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Is this meant to be merged with the current upstream? I'm guessing it needs backend PDB functionality to fully implement, shouldn't it be added later?

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@dzhidzhoev dzhidzhoev Jun 2, 2026

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It does not strictly require PDB emission functionality.
It would be nice to merge this on top of ILDB part emission patch, but it's not on review as for now. I can postpone sending this PR to LLVM repo if needed.

if (!SourceInDebugModule) {
LLVMContext &Ctx = M.getContext();
MDString *EmptyString = MDString::get(Ctx, "");
replaceNamedMetadataArray(M, "dx.source.contents",
{EmptyString, EmptyString});
replaceNamedMetadataArray(M, "dx.source.defines", {});
replaceNamedMetadataArray(M, "dx.source.mainFileName", {EmptyString});
replaceNamedMetadataArray(M, "dx.source.args", {});
}
const auto DIMap = DXILDebugInfoPass::run(M);
WriteDXILToFile(M, OS, DIMap);

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56 changes: 56 additions & 0 deletions llvm/test/CodeGen/DirectX/ContainerData/SourceInfo-Strip.ll
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@@ -0,0 +1,56 @@
; Compare source info emission with and without --dx-source-in-debug-module flag.

; RUN: llc %s --filetype=obj -o %t.dxbc
; RUN: llvm-objcopy --dump-section=DXIL=%t.dxil.bc %t.dxbc
; RUN: llvm-dis %t.dxil.bc -o - | FileCheck %s --check-prefix=ILDB-DIS

; RUN: llc %s --filetype=obj -o %t.dxbc --dx-source-in-debug-module
; RUN: llvm-objcopy --dump-section=DXIL=%t.dxil.bc %t.dxbc
; RUN: llvm-dis %t.dxil.bc -o - | FileCheck %s --check-prefix=ILDB-SOURCE-DIS

; Without the flag, dx.source should be replaced with dummy metadata.
; ILDB-DIS: !dx.source.contents = !{![[CONTENTS:[0-9]+]]}
; ILDB-DIS: !dx.source.defines = !{![[EMPTY_ARR:[0-9]+]]}
; ILDB-DIS: !dx.source.mainFileName = !{![[MAIN:[0-9]+]]}
; ILDB-DIS: !dx.source.args = !{![[EMPTY_ARR]]}
; ILDB-DIS: ![[CONTENTS]] = !{!"", !""}
; ILDB-DIS: ![[EMPTY_ARR]] = !{}
; ILDB-DIS: ![[MAIN]] = !{!""}

; With the flag, dx.source should be be preserved.
; ILDB-SOURCE-DIS: !dx.source.args = !{![[ARGS:[0-9]+]]}
; ILDB-SOURCE-DIS: !dx.source.contents = !{![[FILE1:[0-9]+]], ![[FILE2:[0-9]+]], ![[FILE3:[0-9]+]]}
; ILDB-SOURCE-DIS: !dx.source.mainFileName = !{![[MAIN:[0-9]+]]}
; ILDB-SOURCE-DIS: !dx.source.defines = !{![[DEFINES:[0-9]+]]}
; ILDB-SOURCE-DIS: ![[FILE1]] = !{!"C:\\dx-source-metadata.hlsl",
; ILDB-SOURCE-DIS: ![[FILE2]] = !{!"C:\\a.hlsl"
; ILDB-SOURCE-DIS: ![[FILE3]] = !{!"C:\\b.hlsl"
; ILDB-SOURCE-DIS: ![[MAIN]] = !{!"C:\\dx-source-metadata.hlsl"}
; ILDB-SOURCE-DIS: ![[DEFINES]] = !{!"USER_DEF0=42", !"USER_DEF1=43"}

target triple = "dxilv1.3-pc-shadermodel6.3-library"

define float @_Z3fooff(float %a, float %b) {
entry:
%add = fadd float %a, %b
ret float %add
}

!llvm.dbg.cu = !{!4}
!llvm.module.flags = !{!6, !7}

!dx.source.args = !{!0}
!dx.source.contents = !{!1, !2, !3}
!dx.source.mainFileName = !{!8}
!dx.source.defines = !{!9}

!0 = !{!"-g", !"-Tlib_6_3", !"-DUSER_DEF0=42", !"-DUSER_DEF1=43", !"C:\\\\dx-source-metadata.hlsl"}
!1 = !{!"C:\\dx-source-metadata.hlsl", !"#include \22a.hlsl\22\0A#include \22b.hlsl\22\0A\0Afloat foo(float a, float b) {\0A return a + b;\0A}\0A"}
!2 = !{!"C:\\a.hlsl", !"#include \22b.hlsl\22\0A"}
!3 = !{!"C:\\b.hlsl", !"#include <c.hlsl>\0A"}
!4 = distinct !DICompileUnit(language: DW_LANG_C99, file: !5, emissionKind: FullDebug)
!5 = !DIFile(filename: "dx-source-metadata.hlsl", directory: "C:\\")
!6 = !{i32 2, !"Dwarf Version", i32 4}
!7 = !{i32 2, !"Debug Info Version", i32 3}
!8 = !{!"C:\\dx-source-metadata.hlsl"}
!9 = !{!"USER_DEF0=42", !"USER_DEF1=43"}