Merging r351387, r351765, and r353374:

Merging r351387, r351765, and r353374:

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r351387 | jfb | 2019-01-16 23:22:38 +0100 (Wed, 16 Jan 2019) | 7 lines

[NFC] Factor out + document build requirements

Summary: This change factors out compiler checking / warning, and documents LLVM_FORCE_USE_OLD_TOOLCHAIN. It doesn't introduce any functional changes nor policy changes, these will come late.

Subscribers: mgorny, jkorous, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D56799
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r351765 | jfb | 2019-01-22 00:53:52 +0100 (Tue, 22 Jan 2019) | 24 lines

Document toolchain update policy

Summary:
Capture the current agreed-upon toolchain update policy based on the following
discussions:

  - LLVM dev meeting 2018 BoF "Migrating to C++14, and beyond!"
    llvm.org/devmtg/2018-10/talk-abstracts.html#bof3
  - A Short Policy Proposal Regarding Host Compilers
    lists.llvm.org/pipermail/llvm-dev/2018-May/123238.html
  - Using C++14 code in LLVM (2018)
    lists.llvm.org/pipermail/llvm-dev/2018-May/123182.html
  - Using C++14 code in LLVM (2017)
    lists.llvm.org/pipermail/llvm-dev/2017-October/118673.html
  - Using C++14 code in LLVM (2016)
    lists.llvm.org/pipermail/llvm-dev/2016-October/105483.html
  - Document and Enforce new Host Compiler Policy
    llvm.org/D47073
  - Require GCC 5.1 and LLVM 3.5 at a minimum
    llvm.org/D46723

Subscribers: jkorous, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D56819
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r353374 | jfb | 2019-02-07 06:20:00 +0100 (Thu, 07 Feb 2019) | 12 lines

Bump minimum toolchain version

Summary:
The RFC on moving past C++11 got good traction:
  http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html

This patch therefore bumps the toolchain versions according to our policy:
  llvm.org/docs/DeveloperPolicy.html#toolchain

Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, mehdi_amini, jyknight, rsmith, chandlerc, smeenai, hans, reames, lattner, lhames, erichkeane

Differential Revision: https://reviews.llvm.org/D57264
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_80@353512 91177308-0d34-0410-b5e6-96231b3b80d8