35 lines
1.3 KiB
Markdown
35 lines
1.3 KiB
Markdown
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# Mac and iOS hermetic toolchain instructions
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The following is a short explanation of why we use a the hermetic toolchain
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and instructions on how to roll a new toolchain. This toolchain is only
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available to Googlers and infra bots.
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## How to roll a new hermetic toolchain.
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1. Download a new version of Xcode, and confirm either mac or ios builds
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properly with this new version.
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2. Create a new CIPD package by moving Xcode.app to the `build/` directory, then
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follow the instructions in
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[build/xcode_binaries.yaml](../xcode_binaries.yaml).
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The CIPD package creates a subset of the toolchain necessary for a build.
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2. Create a CL with the updated `MAC_BINARIES_TAG` in
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[mac_toolchain.py](../mac_toolchain.py) with the version created by the
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previous command.
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3. Run the CL through the trybots to confirm the roll works.
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## Why we use a hermetic toolchain.
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Building Chrome Mac currently requires many binaries that come bundled with
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Xcode, as well the macOS and iphoneOS SDK (also bundled with Xcode). Note that
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Chrome ships its own version of clang (compiler), but is dependent on Xcode
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for these other binaries. Using a hermetic toolchain has two main benefits:
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1. Build Chrome with a well-defined toolchain (rather than whatever happens to
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be installed on the machine).
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2. Easily roll/update the toolchain.
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