Extract WASM section model

[jtschuster]

Summary

This is the first PR in a four-PR stack that extracts a base WasmObjectWriter to be shared between NativeAOT and ReadyToRun. This one mostly just moves code related to WasmSection around and adds a WasmSections abstraction.

• Extract the existing WASM and embedded WebCIL section representations into dedicated files.
• Add WasmSections as an abstraction to track and retrieve sections by name or section index.
• Preserve the existing section creation policy and emitted output.

This layer is intended to be mechanical and not introduce changes to behavior.

Stack

1. Extract WASM section model #131770 — Extract WASM section model (this PR)
2. Add typed self-counting WASM sections #131771 — Add typed self-counting WASM sections
3. Rename WasmObjectWriter to WebCilObjectWriter #131772 — Introduce WebCIL object writer type
4. Move shared WASM logic to base writer #131778 — Move shared WASM logic to base writer

Note

This PR description was generated with GitHub Copilot assistance.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

This PR refactors the WASM object writer’s section handling by extracting section-related types into dedicated files and introducing a small WasmSections helper to centralize section storage and name→index lookup.

Changes:

• Replace the writer’s raw List<WasmSection> + name dictionary with a WasmSections wrapper.
• Move WasmSection, WasmDataSection, WasmDataSegment, and WebcilSection out of WasmObjectWriter.cs into separate source files.
• Update ILCompiler.ReadyToRun.csproj to compile the newly extracted WASM object-writer sources.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/coreclr/tools/Common/Compiler/ObjectWriter/WasmObjectWriter.cs	Switch to WasmSections and update section lookups / counts after type extraction.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs	New extracted WebcilSection implementation for READYTORUN Webcil-wrapped data sections.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSections.cs	New wrapper for section list + name→index mapping.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSection.cs	New extracted base section type (header encoding / emit + prepend count).
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSegment.cs	New extracted data-segment type used by the combined data section emission.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSection.cs	New extracted data section that emits multiple segments with alignment/padding.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Add compile includes for the newly extracted WASM object-writer files.

Suppressed comments (1)

src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs:42

• After removing the redundant _stream field, the overrides should also use the inherited Stream property so the implementation stays consistent with the base state.

 public override int EncodeSize()
{
return (int)_stream.Length;
}
public override int Emit(Stream outputFileStream)
{
// Emit the raw contents of this Webcil section followed by any required padding.
_stream.Position = 0;
_stream.CopyTo(outputFileStream);
_paddingHelper.PadStream(outputFileStream, (int)Padding);
return (int)_stream.Length + (int)Padding;
}

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[agocke]

Looked at the second PR, I think it's fine to move the refactoring changes in there instead.

[jtschuster]

Summary

This is the first PR in a four-PR stack that extracts a base WasmObjectWriter to be shared between NativeAOT and ReadyToRun. This one mostly just moves code related to WasmSection around and adds a WasmSections abstraction.

• Extract the existing WASM and embedded WebCIL section representations into dedicated files.
• Add WasmSections as an abstraction to track and retrieve sections by name or section index.
• Preserve the existing section creation policy and emitted output.

This layer is intended to be mechanical and not introduce changes to behavior.

Stack

1. Extract WASM section model #131770 — Extract WASM section model (this PR)
2. Add typed self-counting WASM sections #131771 — Add typed self-counting WASM sections
3. Rename WasmObjectWriter to WebCilObjectWriter #131772 — Introduce WebCIL object writer type
4. Move shared WASM logic to base writer #131778 — Move shared WASM logic to base writer

Note

This PR description was generated with GitHub Copilot assistance.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

This PR refactors the WASM object writer’s section handling by extracting section-related types into dedicated files and introducing a small WasmSections helper to centralize section storage and name→index lookup.

Changes:

• Replace the writer’s raw List<WasmSection> + name dictionary with a WasmSections wrapper.
• Move WasmSection, WasmDataSection, WasmDataSegment, and WebcilSection out of WasmObjectWriter.cs into separate source files.
• Update ILCompiler.ReadyToRun.csproj to compile the newly extracted WASM object-writer sources.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/coreclr/tools/Common/Compiler/ObjectWriter/WasmObjectWriter.cs	Switch to WasmSections and update section lookups / counts after type extraction.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs	New extracted WebcilSection implementation for READYTORUN Webcil-wrapped data sections.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSections.cs	New wrapper for section list + name→index mapping.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSection.cs	New extracted base section type (header encoding / emit + prepend count).
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSegment.cs	New extracted data-segment type used by the combined data section emission.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSection.cs	New extracted data section that emits multiple segments with alignment/padding.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Add compile includes for the newly extracted WASM object-writer files.

Suppressed comments (1)

src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs:42

• After removing the redundant _stream field, the overrides should also use the inherited Stream property so the implementation stays consistent with the base state.

 public override int EncodeSize()
{
return (int)_stream.Length;
}
public override int Emit(Stream outputFileStream)
{
// Emit the raw contents of this Webcil section followed by any required padding.
_stream.Position = 0;
_stream.CopyTo(outputFileStream);
_paddingHelper.PadStream(outputFileStream, (int)Padding);
return (int)_stream.Length + (int)Padding;
}

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[agocke]

Looked at the second PR, I think it's fine to move the refactoring changes in there instead.

[jtschuster]

Summary

This is the first PR in a four-PR stack that extracts a base WasmObjectWriter to be shared between NativeAOT and ReadyToRun. This one mostly just moves code related to WasmSection around and adds a WasmSections abstraction.

• Extract the existing WASM and embedded WebCIL section representations into dedicated files.
• Add WasmSections as an abstraction to track and retrieve sections by name or section index.
• Preserve the existing section creation policy and emitted output.

This layer is intended to be mechanical and not introduce changes to behavior.

Stack

1. Extract WASM section model #131770 — Extract WASM section model (this PR)
2. Add typed self-counting WASM sections #131771 — Add typed self-counting WASM sections
3. Rename WasmObjectWriter to WebCilObjectWriter #131772 — Introduce WebCIL object writer type
4. Move shared WASM logic to base writer #131778 — Move shared WASM logic to base writer

Note

This PR description was generated with GitHub Copilot assistance.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

This PR refactors the WASM object writer’s section handling by extracting section-related types into dedicated files and introducing a small WasmSections helper to centralize section storage and name→index lookup.

Changes:

• Replace the writer’s raw List<WasmSection> + name dictionary with a WasmSections wrapper.
• Move WasmSection, WasmDataSection, WasmDataSegment, and WebcilSection out of WasmObjectWriter.cs into separate source files.
• Update ILCompiler.ReadyToRun.csproj to compile the newly extracted WASM object-writer sources.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/coreclr/tools/Common/Compiler/ObjectWriter/WasmObjectWriter.cs	Switch to WasmSections and update section lookups / counts after type extraction.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs	New extracted WebcilSection implementation for READYTORUN Webcil-wrapped data sections.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSections.cs	New wrapper for section list + name→index mapping.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSection.cs	New extracted base section type (header encoding / emit + prepend count).
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSegment.cs	New extracted data-segment type used by the combined data section emission.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSection.cs	New extracted data section that emits multiple segments with alignment/padding.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Add compile includes for the newly extracted WASM object-writer files.

Suppressed comments (1)

src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs:42

• After removing the redundant _stream field, the overrides should also use the inherited Stream property so the implementation stays consistent with the base state.

 public override int EncodeSize()
{
return (int)_stream.Length;
}
public override int Emit(Stream outputFileStream)
{
// Emit the raw contents of this Webcil section followed by any required padding.
_stream.Position = 0;
_stream.CopyTo(outputFileStream);
_paddingHelper.PadStream(outputFileStream, (int)Padding);
return (int)_stream.Length + (int)Padding;
}

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[agocke]

Looked at the second PR, I think it's fine to move the refactoring changes in there instead.

[jtschuster]

Summary

This is the first PR in a four-PR stack that extracts a base WasmObjectWriter to be shared between NativeAOT and ReadyToRun. This one mostly just moves code related to WasmSection around and adds a WasmSections abstraction.

• Extract the existing WASM and embedded WebCIL section representations into dedicated files.
• Add WasmSections as an abstraction to track and retrieve sections by name or section index.
• Preserve the existing section creation policy and emitted output.

This layer is intended to be mechanical and not introduce changes to behavior.

Stack

1. Extract WASM section model #131770 — Extract WASM section model (this PR)
2. Add typed self-counting WASM sections #131771 — Add typed self-counting WASM sections
3. Rename WasmObjectWriter to WebCilObjectWriter #131772 — Introduce WebCIL object writer type
4. Move shared WASM logic to base writer #131778 — Move shared WASM logic to base writer

Note

This PR description was generated with GitHub Copilot assistance.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

This PR refactors the WASM object writer’s section handling by extracting section-related types into dedicated files and introducing a small WasmSections helper to centralize section storage and name→index lookup.

Changes:

• Replace the writer’s raw List<WasmSection> + name dictionary with a WasmSections wrapper.
• Move WasmSection, WasmDataSection, WasmDataSegment, and WebcilSection out of WasmObjectWriter.cs into separate source files.
• Update ILCompiler.ReadyToRun.csproj to compile the newly extracted WASM object-writer sources.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/coreclr/tools/Common/Compiler/ObjectWriter/WasmObjectWriter.cs	Switch to WasmSections and update section lookups / counts after type extraction.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs	New extracted WebcilSection implementation for READYTORUN Webcil-wrapped data sections.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSections.cs	New wrapper for section list + name→index mapping.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSection.cs	New extracted base section type (header encoding / emit + prepend count).
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSegment.cs	New extracted data-segment type used by the combined data section emission.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSection.cs	New extracted data section that emits multiple segments with alignment/padding.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Add compile includes for the newly extracted WASM object-writer files.

Suppressed comments (1)

src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs:42

• After removing the redundant _stream field, the overrides should also use the inherited Stream property so the implementation stays consistent with the base state.

 public override int EncodeSize()
{
return (int)_stream.Length;
}
public override int Emit(Stream outputFileStream)
{
// Emit the raw contents of this Webcil section followed by any required padding.
_stream.Position = 0;
_stream.CopyTo(outputFileStream);
_paddingHelper.PadStream(outputFileStream, (int)Padding);
return (int)_stream.Length + (int)Padding;
}

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[agocke]

Looked at the second PR, I think it's fine to move the refactoring changes in there instead.

[jtschuster]

Summary

This is the first PR in a four-PR stack that extracts a base WasmObjectWriter to be shared between NativeAOT and ReadyToRun. This one mostly just moves code related to WasmSection around and adds a WasmSections abstraction.

• Extract the existing WASM and embedded WebCIL section representations into dedicated files.
• Add WasmSections as an abstraction to track and retrieve sections by name or section index.
• Preserve the existing section creation policy and emitted output.

This layer is intended to be mechanical and not introduce changes to behavior.

Stack

1. Extract WASM section model #131770 — Extract WASM section model (this PR)
2. Add typed self-counting WASM sections #131771 — Add typed self-counting WASM sections
3. Rename WasmObjectWriter to WebCilObjectWriter #131772 — Introduce WebCIL object writer type
4. Move shared WASM logic to base writer #131778 — Move shared WASM logic to base writer

Note

This PR description was generated with GitHub Copilot assistance.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

This PR refactors the WASM object writer’s section handling by extracting section-related types into dedicated files and introducing a small WasmSections helper to centralize section storage and name→index lookup.

Changes:

• Replace the writer’s raw List<WasmSection> + name dictionary with a WasmSections wrapper.
• Move WasmSection, WasmDataSection, WasmDataSegment, and WebcilSection out of WasmObjectWriter.cs into separate source files.
• Update ILCompiler.ReadyToRun.csproj to compile the newly extracted WASM object-writer sources.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/coreclr/tools/Common/Compiler/ObjectWriter/WasmObjectWriter.cs	Switch to WasmSections and update section lookups / counts after type extraction.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs	New extracted WebcilSection implementation for READYTORUN Webcil-wrapped data sections.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSections.cs	New wrapper for section list + name→index mapping.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSection.cs	New extracted base section type (header encoding / emit + prepend count).
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSegment.cs	New extracted data-segment type used by the combined data section emission.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSection.cs	New extracted data section that emits multiple segments with alignment/padding.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Add compile includes for the newly extracted WASM object-writer files.

Suppressed comments (1)

src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs:42

• After removing the redundant _stream field, the overrides should also use the inherited Stream property so the implementation stays consistent with the base state.

 public override int EncodeSize()
{
return (int)_stream.Length;
}
public override int Emit(Stream outputFileStream)
{
// Emit the raw contents of this Webcil section followed by any required padding.
_stream.Position = 0;
_stream.CopyTo(outputFileStream);
_paddingHelper.PadStream(outputFileStream, (int)Padding);
return (int)_stream.Length + (int)Padding;
}

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[agocke]

Looked at the second PR, I think it's fine to move the refactoring changes in there instead.

[jtschuster]

Summary

This is the first PR in a four-PR stack that extracts a base WasmObjectWriter to be shared between NativeAOT and ReadyToRun. This one mostly just moves code related to WasmSection around and adds a WasmSections abstraction.

• Extract the existing WASM and embedded WebCIL section representations into dedicated files.
• Add WasmSections as an abstraction to track and retrieve sections by name or section index.
• Preserve the existing section creation policy and emitted output.

This layer is intended to be mechanical and not introduce changes to behavior.

Stack

1. Extract WASM section model #131770 — Extract WASM section model (this PR)
2. Add typed self-counting WASM sections #131771 — Add typed self-counting WASM sections
3. Rename WasmObjectWriter to WebCilObjectWriter #131772 — Introduce WebCIL object writer type
4. Move shared WASM logic to base writer #131778 — Move shared WASM logic to base writer

Note

This PR description was generated with GitHub Copilot assistance.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

This PR refactors the WASM object writer’s section handling by extracting section-related types into dedicated files and introducing a small WasmSections helper to centralize section storage and name→index lookup.

Changes:

• Replace the writer’s raw List<WasmSection> + name dictionary with a WasmSections wrapper.
• Move WasmSection, WasmDataSection, WasmDataSegment, and WebcilSection out of WasmObjectWriter.cs into separate source files.
• Update ILCompiler.ReadyToRun.csproj to compile the newly extracted WASM object-writer sources.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/coreclr/tools/Common/Compiler/ObjectWriter/WasmObjectWriter.cs	Switch to WasmSections and update section lookups / counts after type extraction.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs	New extracted WebcilSection implementation for READYTORUN Webcil-wrapped data sections.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSections.cs	New wrapper for section list + name→index mapping.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSection.cs	New extracted base section type (header encoding / emit + prepend count).
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSegment.cs	New extracted data-segment type used by the combined data section emission.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSection.cs	New extracted data section that emits multiple segments with alignment/padding.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Add compile includes for the newly extracted WASM object-writer files.

Suppressed comments (1)

src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs:42

• After removing the redundant _stream field, the overrides should also use the inherited Stream property so the implementation stays consistent with the base state.

 public override int EncodeSize()
{
return (int)_stream.Length;
}
public override int Emit(Stream outputFileStream)
{
// Emit the raw contents of this Webcil section followed by any required padding.
_stream.Position = 0;
_stream.CopyTo(outputFileStream);
_paddingHelper.PadStream(outputFileStream, (int)Padding);
return (int)_stream.Length + (int)Padding;
}

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[agocke]

Looked at the second PR, I think it's fine to move the refactoring changes in there instead.

[jtschuster]

Summary

This is the first PR in a four-PR stack that extracts a base WasmObjectWriter to be shared between NativeAOT and ReadyToRun. This one mostly just moves code related to WasmSection around and adds a WasmSections abstraction.

• Extract the existing WASM and embedded WebCIL section representations into dedicated files.
• Add WasmSections as an abstraction to track and retrieve sections by name or section index.
• Preserve the existing section creation policy and emitted output.

This layer is intended to be mechanical and not introduce changes to behavior.

Stack

1. Extract WASM section model #131770 — Extract WASM section model (this PR)
2. Add typed self-counting WASM sections #131771 — Add typed self-counting WASM sections
3. Rename WasmObjectWriter to WebCilObjectWriter #131772 — Introduce WebCIL object writer type
4. Move shared WASM logic to base writer #131778 — Move shared WASM logic to base writer

Note

This PR description was generated with GitHub Copilot assistance.

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

This PR refactors the WASM object writer’s section handling by extracting section-related types into dedicated files and introducing a small WasmSections helper to centralize section storage and name→index lookup.

Changes:

• Replace the writer’s raw List<WasmSection> + name dictionary with a WasmSections wrapper.
• Move WasmSection, WasmDataSection, WasmDataSegment, and WebcilSection out of WasmObjectWriter.cs into separate source files.
• Update ILCompiler.ReadyToRun.csproj to compile the newly extracted WASM object-writer sources.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/coreclr/tools/Common/Compiler/ObjectWriter/WasmObjectWriter.cs	Switch to WasmSections and update section lookups / counts after type extraction.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs	New extracted WebcilSection implementation for READYTORUN Webcil-wrapped data sections.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSections.cs	New wrapper for section list + name→index mapping.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSection.cs	New extracted base section type (header encoding / emit + prepend count).
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSegment.cs	New extracted data-segment type used by the combined data section emission.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSection.cs	New extracted data section that emits multiple segments with alignment/padding.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Add compile includes for the newly extracted WASM object-writer files.

Suppressed comments (1)

src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs:42

• After removing the redundant _stream field, the overrides should also use the inherited Stream property so the implementation stays consistent with the base state.

 public override int EncodeSize()
{
return (int)_stream.Length;
}
public override int Emit(Stream outputFileStream)
{
// Emit the raw contents of this Webcil section followed by any required padding.
_stream.Position = 0;
_stream.CopyTo(outputFileStream);
_paddingHelper.PadStream(outputFileStream, (int)Padding);
return (int)_stream.Length + (int)Padding;
}

[azure-pipelines]

Azure Pipelines:
Successfully started running 3 pipeline(s).
13 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[agocke]

Looked at the second PR, I think it's fine to move the refactoring changes in there instead.

[jtschuster]

Summary

This is the first PR in a four-PR stack that extracts a base WasmObjectWriter to be shared between NativeAOT and ReadyToRun. This one mostly just moves code related to WasmSection around and adds a WasmSections abstraction.

• Extract the existing WASM and embedded WebCIL section representations into dedicated files.
• Add WasmSections as an abstraction to track and retrieve sections by name or section index.
• Preserve the existing section creation policy and emitted output.

This layer is intended to be mechanical and not introduce changes to behavior.

Stack

1. Extract WASM section model #131770 — Extract WASM section model (this PR)
2. Add typed self-counting WASM sections #131771 — Add typed self-counting WASM sections
3. Rename WasmObjectWriter to WebCilObjectWriter #131772 — Introduce WebCIL object writer type
4. Move shared WASM logic to base writer #131778 — Move shared WASM logic to base writer

Note

This PR description was generated with GitHub Copilot assistance.

[azure-pipelines]

Azure Pipelines:
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[Copilot]

Pull request overview

This PR refactors the WASM object writer’s section handling by extracting section-related types into dedicated files and introducing a small WasmSections helper to centralize section storage and name→index lookup.

Changes:

• Replace the writer’s raw List<WasmSection> + name dictionary with a WasmSections wrapper.
• Move WasmSection, WasmDataSection, WasmDataSegment, and WebcilSection out of WasmObjectWriter.cs into separate source files.
• Update ILCompiler.ReadyToRun.csproj to compile the newly extracted WASM object-writer sources.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/coreclr/tools/Common/Compiler/ObjectWriter/WasmObjectWriter.cs	Switch to WasmSections and update section lookups / counts after type extraction.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs	New extracted WebcilSection implementation for READYTORUN Webcil-wrapped data sections.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSections.cs	New wrapper for section list + name→index mapping.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmSection.cs	New extracted base section type (header encoding / emit + prepend count).
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSegment.cs	New extracted data-segment type used by the combined data section emission.
src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WasmDataSection.cs	New extracted data section that emits multiple segments with alignment/padding.
src/coreclr/tools/aot/ILCompiler.ReadyToRun/ILCompiler.ReadyToRun.csproj	Add compile includes for the newly extracted WASM object-writer files.

Suppressed comments (1)

src/coreclr/tools/Common/Compiler/ObjectWriter/Wasm/WebcilSection.cs:42

• After removing the redundant _stream field, the overrides should also use the inherited Stream property so the implementation stays consistent with the base state.

 public override int EncodeSize()
{
return (int)_stream.Length;
}
public override int Emit(Stream outputFileStream)
{
// Emit the raw contents of this Webcil section followed by any required padding.
_stream.Position = 0;
_stream.CopyTo(outputFileStream);
_paddingHelper.PadStream(outputFileStream, (int)Padding);
return (int)_stream.Length + (int)Padding;
}

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[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
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[agocke]

Looked at the second PR, I think it's fine to move the refactoring changes in there instead.