From fc0d98fa1a3231247e4fe8b93826ee56db213996 Mon Sep 17 00:00:00 2001
From: Billy Robert O'Neal III <bion@microsoft.com>
Date: Tue, 22 Sep 2020 20:01:02 -0700
Subject: [PATCH 1/6] Initial 'scaffold' to move the 'unstable' queue into the
 open.

---
 .../azure-pipelines/test-modified-ports.ps1   |  56 +++++----
 .../windows-unstable/README.md                |   4 +
 .../windows-unstable/azure-pipelines.yml      |  30 +++++
 .../azure-pipelines/windows-unstable/job.yml  |  51 ++++++++
 .../azure-pipelines/windows/create-vmss.ps1   | 109 ++++++++++++------
 .../windows/initialize-environment.ps1        |  23 ++--
 6 files changed, 200 insertions(+), 73 deletions(-)
 create mode 100644 scripts/azure-pipelines/windows-unstable/README.md
 create mode 100644 scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
 create mode 100644 scripts/azure-pipelines/windows-unstable/job.yml

diff --git a/scripts/azure-pipelines/test-modified-ports.ps1 b/scripts/azure-pipelines/test-modified-ports.ps1
index 773c55d138cdf7..15cb8131f5da01 100755
--- a/scripts/azure-pipelines/test-modified-ports.ps1
+++ b/scripts/azure-pipelines/test-modified-ports.ps1
@@ -9,18 +9,20 @@ Runs the 'Test Modified Ports' part of the vcpkg CI system for all platforms.
 .PARAMETER Triplet
 The triplet to test.
 
-.PARAMETER ArchivesRoot
-The location where the binary caching archives are stored. Shared across runs of this script.
-
 .PARAMETER WorkingRoot
 The location used as scratch space for 'installed', 'packages', and 'buildtrees' vcpkg directories.
 
 .PARAMETER ArtifactStagingDirectory
 The Azure Pipelines artifacts directory. If not supplied, defaults to the current directory.
 
+.PARAMETER ArchivesRoot
+The location where the binary caching archives are stored. Shared across runs of this script. If
+this parameter is not set, binary caching will not be used.
+
 .PARAMETER BuildReason
-The reason Azure Pipelines is running this script (controls whether Binary Caching is used). If not
-supplied, binary caching will be used.
+The reason Azure Pipelines is running this script (controls in which mode Binary Caching is used).
+If ArchivesRoot is not set, this parameter has no effect. If ArchivesRoot is set and this is not,
+binary caching will default to read-write mode.
 #>
 
 [CmdletBinding()]
@@ -30,12 +32,10 @@ Param(
     [string]$Triplet,
     [Parameter(Mandatory = $true)]
     [ValidateNotNullOrEmpty()]
-    $ArchivesRoot,
-    [Parameter(Mandatory = $true)]
-    [ValidateNotNullOrEmpty()]
     $WorkingRoot,
     [ValidateNotNullOrEmpty()]
     $ArtifactStagingDirectory = '.',
+    $ArchivesRoot = $null,
     $BuildReason = $null
 )
 
@@ -48,29 +48,39 @@ $env:VCPKG_DOWNLOADS = Join-Path $WorkingRoot 'downloads'
 $buildtreesRoot = Join-Path $WorkingRoot 'buildtrees'
 $installRoot = Join-Path $WorkingRoot 'installed'
 $packagesRoot = Join-Path $WorkingRoot 'packages'
-$commonArgs = @(
-    '--binarycaching',
+
+$usingBinaryCaching = -Not ([string]::IsNullOrWhiteSpace($ArchivesRoot))
+$commonArgs = @()
+if ($usingBinaryCaching) {
+    $commonArgs += @('--binarycaching')
+} else {
+    $commonArgs += @('--no-binarycaching')
+}
+
+$commonArgs += @(
     "--x-buildtrees-root=$buildtreesRoot",
     "--x-install-root=$installRoot",
     "--x-packages-root=$packagesRoot",
     "--overlay-ports=scripts/test_ports"
 )
 
-$binaryCachingMode = 'readwrite'
 $skipFailures = $false
-if ([string]::IsNullOrWhiteSpace($BuildReason)) {
-    Write-Host 'Build reason not specified, defaulting to using binary caching in read write mode.'
-}
-elseif ($BuildReason -eq 'PullRequest') {
-    Write-Host 'Build reason was Pull Request, using binary caching in read write mode, skipping failures.'
-    $skipFailures = $true
+if ($usingBinaryCaching) {
+    $binaryCachingMode = 'readwrite'
+    if ([string]::IsNullOrWhiteSpace($BuildReason)) {
+        Write-Host 'Build reason not specified, defaulting to using binary caching in read write mode.'
+    }
+    elseif ($BuildReason -eq 'PullRequest') {
+        Write-Host 'Build reason was Pull Request, using binary caching in read write mode, skipping failures.'
+        $skipFailures = $true
+    }
+    else {
+        Write-Host "Build reason was $BuildReason, using binary caching in write only mode."
+        $binaryCachingMode = 'write'
+    }
+
+    $commonArgs += @("--x-binarysource=clear;files,$ArchivesRoot,$binaryCachingMode")
 }
-else {
-    Write-Host "Build reason was $BuildReason, using binary caching in write only mode."
-    $binaryCachingMode = 'write'
-}
-
-$commonArgs += @("--x-binarysource=clear;files,$ArchivesRoot,$binaryCachingMode")
 
 if ($Triplet -eq 'x64-linux') {
     $env:HOME = '/home/agent'
diff --git a/scripts/azure-pipelines/windows-unstable/README.md b/scripts/azure-pipelines/windows-unstable/README.md
new file mode 100644
index 00000000000000..d60367247ac768
--- /dev/null
+++ b/scripts/azure-pipelines/windows-unstable/README.md
@@ -0,0 +1,4 @@
+The "unstable" build is used internally by Microsoft to test prerelease versions
+of our C++ compiler; not seeing results from these build definitions in the 
+GitHub portal is normal as these builds depend on acquisition of private
+compiler bits that aren't yet shipping.
diff --git a/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml b/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
new file mode 100644
index 00000000000000..899047021b4c8a
--- /dev/null
+++ b/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
@@ -0,0 +1,30 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: MIT
+#
+variables:
+  unstable-pool: 'VcpkgUnstable-2020-09-01'
+
+jobs:
+- template: job.yml
+  parameters:
+    triplet: x86-windows
+    jobName: x86_windows
+    poolName: $(unstable-pool)
+
+- template: job.yml
+  parameters:
+    triplet: x64-windows
+    jobName: x64_windows
+    poolName: $(unstable-pool)
+
+- template: job.yml
+  parameters:
+    triplet: x64-windows-static
+    jobName: x64_windows_static
+    poolName: $(unstable-pool)
+
+- template: job.yml
+  parameters:
+    triplet: x64-uwp
+    jobName: x64_uwp
+    poolName: $(unstable-pool)
diff --git a/scripts/azure-pipelines/windows-unstable/job.yml b/scripts/azure-pipelines/windows-unstable/job.yml
new file mode 100644
index 00000000000000..47e981153a94eb
--- /dev/null
+++ b/scripts/azure-pipelines/windows-unstable/job.yml
@@ -0,0 +1,51 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: MIT
+#
+
+jobs:
+- job: ${{ parameters.jobName }}
+  pool:
+    name: ${{ parameters.poolName }}
+  workspace:
+    clean: resources
+  timeoutInMinutes: 1440 # 1 day
+  variables:
+  - name: WORKING_ROOT
+    value: D:\
+  - name: VCPKG_DOWNLOADS
+    value: D:\downloads
+
+  steps:
+  - task: PowerShell@2
+    displayName: 'Initialize Environment'
+    inputs:
+      filePath: 'scripts/azure-pipelines/windows/initialize-environment.ps1'
+      pwsh: true
+  - task: PowerShell@2
+    displayName: 'Report on Disk Space'
+    condition: always()
+    inputs:
+      filePath: 'scripts/azure-pipelines/windows/disk-space.ps1'
+      pwsh: true
+  # Note: D: is the Azure machines' temporary disk.
+  - script: .\bootstrap-vcpkg.bat
+    displayName: 'Build vcpkg'
+  - task: PowerShell@2
+    displayName: '*** Test Modified Ports and Prepare Test Logs ***'
+    inputs:
+      failOnStderr: true
+      filePath: 'scripts/azure-pipelines/test-modified-ports.ps1'
+      arguments: '-Triplet ${{ parameters.triplet }} -BuildReason $(Build.Reason) -WorkingRoot ${{ variables.WORKING_ROOT }} -ArtifactsDirectory $(System.ArtifactsDirectory)'
+      pwsh: true
+  - task: PowerShell@2
+    displayName: 'Report on Disk Space After Build'
+    condition: always()
+    inputs:
+      filePath: 'scripts/azure-pipelines/windows/disk-space.ps1'
+      pwsh: true
+  - task: PublishBuildArtifacts@1
+    displayName: 'Publish Artifact: failure logs for ${{ parameters.triplet }}'
+    inputs:
+      PathtoPublish: '$(System.ArtifactsDirectory)\failure-logs'
+      ArtifactName: 'failure logs for ${{ parameters.triplet }}'
+    condition: failed()
diff --git a/scripts/azure-pipelines/windows/create-vmss.ps1 b/scripts/azure-pipelines/windows/create-vmss.ps1
index 3bb89ee259da45..1fcec50ed2fb8a 100644
--- a/scripts/azure-pipelines/windows/create-vmss.ps1
+++ b/scripts/azure-pipelines/windows/create-vmss.ps1
@@ -14,10 +14,28 @@ for more information.
 This script assumes you have installed Azure tools into PowerShell by following the instructions
 at https://docs.microsoft.com/en-us/powershell/azure/install-az-ps?view=azps-3.6.1
 or are running from Azure Cloud Shell.
+
+.PARAMETER Unstable
+If this parameter is set, the machine is configured for use in the "unstable" pool used for testing
+the compiler rather than for testing vcpkg. Differences:
+* The machine prefix is changed to VcpkgUnstable instead of PrWin.
+* No storage account or "archives" share is provisioned.
+* The firewall is not opened to allow communication with Azure Storage.
 #>
 
+[CmdLetBinding()]
+Param(
+  [switch]$Unstable = $false
+)
+
 $Location = 'westus2'
-$Prefix = 'PrWin-' + (Get-Date -Format 'yyyy-MM-dd')
+if ($Unstable) {
+  $Prefix = 'VcpkgUnstable-'
+} else {
+  $Prefix = 'PrWin-'
+}
+
+$Prefix += (Get-Date -Format 'yyyy-MM-dd')
 $VMSize = 'Standard_D16a_v4'
 $ProtoVMName = 'PROTOTYPE'
 $LiveVMPrefix = 'BUILD'
@@ -26,6 +44,10 @@ $ErrorActionPreference = 'Stop'
 
 $ProgressActivity = 'Creating Scale Set'
 $TotalProgress = 12
+if ($Unstable) {
+  $TotalProgress -= 1 # skipping the archives share part
+}
+
 $CurrentProgress = 1
 
 Import-Module "$PSScriptRoot/../create-vmss-helpers.psm1" -DisableNameChecking
@@ -84,17 +106,19 @@ $allowGit = New-AzNetworkSecurityRuleConfig `
   -DestinationAddressPrefix * `
   -DestinationPortRange 9418
 
-$allowStorage = New-AzNetworkSecurityRuleConfig `
-  -Name AllowStorage `
-  -Description 'Allow Storage' `
-  -Access Allow `
-  -Protocol * `
-  -Direction Outbound `
-  -Priority 1011 `
-  -SourceAddressPrefix VirtualNetwork `
-  -SourcePortRange * `
-  -DestinationAddressPrefix Storage `
-  -DestinationPortRange *
+if (-Not $Unstable) {
+  $allowStorage = New-AzNetworkSecurityRuleConfig `
+    -Name AllowStorage `
+    -Description 'Allow Storage' `
+    -Access Allow `
+    -Protocol * `
+    -Direction Outbound `
+    -Priority 1011 `
+    -SourceAddressPrefix VirtualNetwork `
+    -SourcePortRange * `
+    -DestinationAddressPrefix Storage `
+    -DestinationPortRange *
+}
 
 $denyEverythingElse = New-AzNetworkSecurityRuleConfig `
   -Name DenyElse `
@@ -109,11 +133,18 @@ $denyEverythingElse = New-AzNetworkSecurityRuleConfig `
   -DestinationPortRange *
 
 $NetworkSecurityGroupName = $ResourceGroupName + 'NetworkSecurity'
+$securityRules = @($allowHttp, $allowDns, $allowGit);
+if (-Not $Unstable) {
+  $securityRules += @($allowStorage)
+}
+
+$securityRules += @($denyEverythingElse)
+
 $NetworkSecurityGroup = New-AzNetworkSecurityGroup `
   -Name $NetworkSecurityGroupName `
   -ResourceGroupName $ResourceGroupName `
   -Location $Location `
-  -SecurityRules @($allowHttp, $allowDns, $allowGit, $allowStorage, $denyEverythingElse)
+  -SecurityRules $securityRules
 
 $SubnetName = $ResourceGroupName + 'Subnet'
 $Subnet = New-AzVirtualNetworkSubnetConfig `
@@ -130,32 +161,34 @@ $VirtualNetwork = New-AzVirtualNetwork `
   -Subnet $Subnet
 
 ####################################################################################################
-Write-Progress `
-  -Activity $ProgressActivity `
-  -Status 'Creating archives storage account' `
-  -PercentComplete (100 / $TotalProgress * $CurrentProgress++)
+if (-Not $Unstable) {
+  Write-Progress `
+    -Activity $ProgressActivity `
+    -Status 'Creating archives storage account' `
+    -PercentComplete (100 / $TotalProgress * $CurrentProgress++)
 
-$StorageAccountName = Sanitize-Name $ResourceGroupName
+  $StorageAccountName = Sanitize-Name $ResourceGroupName
 
-New-AzStorageAccount `
-  -ResourceGroupName $ResourceGroupName `
-  -Location $Location `
-  -Name $StorageAccountName `
-  -SkuName 'Standard_LRS' `
-  -Kind StorageV2
+  New-AzStorageAccount `
+    -ResourceGroupName $ResourceGroupName `
+    -Location $Location `
+    -Name $StorageAccountName `
+    -SkuName 'Standard_LRS' `
+    -Kind StorageV2
 
-$StorageAccountKeys = Get-AzStorageAccountKey `
-  -ResourceGroupName $ResourceGroupName `
-  -Name $StorageAccountName
+  $StorageAccountKeys = Get-AzStorageAccountKey `
+    -ResourceGroupName $ResourceGroupName `
+    -Name $StorageAccountName
 
-$StorageAccountKey = $StorageAccountKeys[0].Value
+  $StorageAccountKey = $StorageAccountKeys[0].Value
 
-$StorageContext = New-AzStorageContext `
-  -StorageAccountName $StorageAccountName `
-  -StorageAccountKey $StorageAccountKey
+  $StorageContext = New-AzStorageContext `
+    -StorageAccountName $StorageAccountName `
+    -StorageAccountKey $StorageAccountKey
 
-New-AzStorageShare -Name 'archives' -Context $StorageContext
-Set-AzStorageShareQuota -ShareName 'archives' -Context $StorageContext -Quota 2048
+  New-AzStorageShare -Name 'archives' -Context $StorageContext
+  Set-AzStorageShareQuota -ShareName 'archives' -Context $StorageContext -Quota 2048
+}
 
 ####################################################################################################
 Write-Progress `
@@ -198,14 +231,18 @@ Write-Progress `
   -Status 'Running provisioning script provision-image.txt (as a .ps1) in VM' `
   -PercentComplete (100 / $TotalProgress * $CurrentProgress++)
 
+$provisionParameters = @{AdminUserPassword = $AdminPW;}
+if (-Not $Unstable) {
+  $provisionParameters['StorageAccountName'] = $StorageAccountName
+  $provisionParameters['StorageAccountKey'] = $StorageAccountKey
+}
+
 $ProvisionImageResult = Invoke-AzVMRunCommand `
   -ResourceGroupName $ResourceGroupName `
   -VMName $ProtoVMName `
   -CommandId 'RunPowerShellScript' `
   -ScriptPath "$PSScriptRoot\provision-image.txt" `
-  -Parameter @{AdminUserPassword = $AdminPW; `
-    StorageAccountName=$StorageAccountName; `
-    StorageAccountKey=$StorageAccountKey;}
+  -Parameter $provisionParameters
 
 Write-Host "provision-image.ps1 output: $($ProvisionImageResult.value.Message)"
 
diff --git a/scripts/azure-pipelines/windows/initialize-environment.ps1 b/scripts/azure-pipelines/windows/initialize-environment.ps1
index 4a252df49b07ed..24520802e4f66a 100644
--- a/scripts/azure-pipelines/windows/initialize-environment.ps1
+++ b/scripts/azure-pipelines/windows/initialize-environment.ps1
@@ -8,23 +8,18 @@ Sets up the environment to run other vcpkg CI steps in an Azure Pipelines job.
 .DESCRIPTION
 This script maps network drives from infrastructure and cleans out anything that
 might have been leftover from a previous run.
-
-.PARAMETER ForceAllPortsToRebuildKey
-A subdirectory / key to use to force a build without any previous run caching,
-if necessary.
 #>
 
-[CmdletBinding()]
-Param(
-    [string]$ForceAllPortsToRebuildKey = ''
-)
-
-$StorageAccountName = $env:StorageAccountName
-$StorageAccountKey = $env:StorageAccountKey
+if ([string]::IsNullOrWhiteSpace($env:StorageAccountName) -or  [string]::IsNullOrWhiteSpace($env:StorageAccountKey)) {
+    Write-Host 'No storage account and/or key set, skipping mount of W:\'
+} else {
+    $StorageAccountName = $env:StorageAccountName
+    $StorageAccountKey = $env:StorageAccountKey
 
-Write-Host 'Setting up archives mount'
-if (-Not (Test-Path W:)) {
-    net use W: "\\$StorageAccountName.file.core.windows.net\archives" /u:"AZURE\$StorageAccountName" $StorageAccountKey
+    Write-Host 'Setting up archives mount'
+    if (-Not (Test-Path W:)) {
+        net use W: "\\$StorageAccountName.file.core.windows.net\archives" /u:"AZURE\$StorageAccountName" $StorageAccountKey
+    }
 }
 
 Write-Host 'Creating downloads directory'

From 58951f7a9da678a8d7ff2662e261b0de077c5650 Mon Sep 17 00:00:00 2001
From: Billy Robert O'Neal III <bion@microsoft.com>
Date: Wed, 23 Sep 2020 18:26:34 -0700
Subject: [PATCH 2/6] Only enable x64-windows for consistency with the old
 infrastructure.

---
 .../windows-unstable/azure-pipelines.yml       | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml b/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
index 899047021b4c8a..1a0b9eade816c2 100644
--- a/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
+++ b/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
@@ -5,26 +5,8 @@ variables:
   unstable-pool: 'VcpkgUnstable-2020-09-01'
 
 jobs:
-- template: job.yml
-  parameters:
-    triplet: x86-windows
-    jobName: x86_windows
-    poolName: $(unstable-pool)
-
 - template: job.yml
   parameters:
     triplet: x64-windows
     jobName: x64_windows
     poolName: $(unstable-pool)
-
-- template: job.yml
-  parameters:
-    triplet: x64-windows-static
-    jobName: x64_windows_static
-    poolName: $(unstable-pool)
-
-- template: job.yml
-  parameters:
-    triplet: x64-uwp
-    jobName: x64_uwp
-    poolName: $(unstable-pool)

From 9227189397834c6198308476ccec8589acd5821b Mon Sep 17 00:00:00 2001
From: Billy Robert O'Neal III <bion@microsoft.com>
Date: Wed, 23 Sep 2020 19:48:28 -0700
Subject: [PATCH 3/6] Add compiler downloading.

---
 .../windows-unstable/azure-pipelines.yml      |  2 +
 .../azure-pipelines/windows-unstable/job.yml  | 41 +++++++++-
 .../rearrange-msvc-drop-layout.ps1            | 75 +++++++++++++++++++
 3 files changed, 117 insertions(+), 1 deletion(-)
 create mode 100644 scripts/azure-pipelines/windows-unstable/rearrange-msvc-drop-layout.ps1

diff --git a/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml b/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
index 1a0b9eade816c2..4c238f56fea6a1 100644
--- a/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
+++ b/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
@@ -3,6 +3,8 @@
 #
 variables:
   unstable-pool: 'VcpkgUnstable-2020-09-01'
+  MSVCBranchName: 'master'
+  DropBuildNumber: ''
 
 jobs:
 - template: job.yml
diff --git a/scripts/azure-pipelines/windows-unstable/job.yml b/scripts/azure-pipelines/windows-unstable/job.yml
index 47e981153a94eb..8697dfe358cb1b 100644
--- a/scripts/azure-pipelines/windows-unstable/job.yml
+++ b/scripts/azure-pipelines/windows-unstable/job.yml
@@ -16,6 +16,46 @@ jobs:
     value: D:\downloads
 
   steps:
+  - task: DownloadBuildArtifacts@0
+    displayName: 'Download DropBuildNumber if not specified'
+    inputs:
+      buildType: specific
+      project: '0bdbc590-a062-4c3f-b0f6-9383f67865ee'
+      pipeline: 8136
+      buildVersionToDownload: latestFromBranch
+      branchName: 'refs/heads/$(MSVCBranchName)'
+      artifactName: BuildNumber
+      downloadPath: 'D:\msvc-drops'
+    condition: eq(variables['DropBuildNumber'], '')
+  - task: PowerShell@2
+    displayName: 'Set DropBuildNumber if not specified'
+    inputs:
+      targetType: inline
+      script: |
+        $DropBuildNumber = Get-Content -Path D:\msvc-drops\BuildNumber\Build.BuildNumber.txt
+        Write-Host "##vso[task.setvariable variable=DropBuildNumber]$DropBuildNumber"
+        Write-Host "Build Number set to: $DropBuildNumber"
+      pwsh: true
+    condition: eq(variables['DropBuildNumber'], '')
+  - task: ms-vscs-artifact.build-tasks.artifactDropDownloadTask-1.artifactDropDownloadTask@0
+    displayName: 'Download msvc x86 ret'
+    inputs:
+      dropServiceURI: 'https://devdiv.artifacts.visualstudio.com/DefaultCollection'
+      buildNumber: 'msvc/builds/$(DropBuildNumber)/x86ret'
+      destinationPath: 'D:\msvc-drops\$(DropBuildNumber)\binaries.x86ret'
+  - task: ms-vscs-artifact.build-tasks.artifactDropDownloadTask-1.artifactDropDownloadTask@0
+    displayName: 'Download msvc amd64 ret'
+    inputs:
+      dropServiceURI: 'https://devdiv.artifacts.visualstudio.com/DefaultCollection'
+      buildNumber: 'msvc/builds/$(DropBuildNumber)/amd64ret'
+      destinationPath: 'D:\msvc-drops\$(DropBuildNumber)\binaries.amd64ret'
+  - task: PowerShell@2
+    displayName: 'Rearrange MSVC Drop Layout'
+    inputs:
+      targetType: filePath
+      filePath: 'scripts/azure-pipelines/windows-unstable/rearrange-msvc-drop-layout.ps1'
+      arguments: '-DropRoot "D:\msvc-drops\$(DropBuildNumber)" -BuildType ret'
+      pwsh: true
   - task: PowerShell@2
     displayName: 'Initialize Environment'
     inputs:
@@ -27,7 +67,6 @@ jobs:
     inputs:
       filePath: 'scripts/azure-pipelines/windows/disk-space.ps1'
       pwsh: true
-  # Note: D: is the Azure machines' temporary disk.
   - script: .\bootstrap-vcpkg.bat
     displayName: 'Build vcpkg'
   - task: PowerShell@2
diff --git a/scripts/azure-pipelines/windows-unstable/rearrange-msvc-drop-layout.ps1 b/scripts/azure-pipelines/windows-unstable/rearrange-msvc-drop-layout.ps1
new file mode 100644
index 00000000000000..d409bc2085516f
--- /dev/null
+++ b/scripts/azure-pipelines/windows-unstable/rearrange-msvc-drop-layout.ps1
@@ -0,0 +1,75 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: MIT
+#
+<#
+.SYNOPSIS
+Moves files from an MSVC compiler drop to the locations where they are installed in a Visual Studio installation.
+
+.PARAMETER DropRoot
+The location where the MSVC compiler drop has been downloaded.
+
+.PARAMETER BuildType
+The MSVC drop build type set with /p:_BuildType when MSVC was built. Defaults to 'ret'.
+
+#>
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory = $true)][string]$DropRoot,
+    [Parameter(Mandatory = $false)][ValidateSet('ret', 'chk')][string]$BuildType = 'ret'
+)
+
+Set-StrictMode -Version Latest
+
+$MSVCRoot = "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC"
+
+$ErrorActionPreference = "Stop"
+
+$tempRoot = "$DropRoot\readytodeploy"
+
+New-Item -ItemType Directory -Path $tempRoot | Out-Null
+
+Write-Host "Rearranging x86$BuildType"
+New-Item -ItemType Directory -Path "$tempRoot\bin\HostX86" | Out-Null
+Move-Item "$DropRoot\binaries.x86$BuildType\bin\i386" "$tempRoot\bin\HostX86\x86"
+Move-Item "$DropRoot\binaries.x86$BuildType\bin\x86_amd64" "$tempRoot\bin\HostX86\x64"
+Move-Item "$DropRoot\binaries.x86$BuildType\bin\x86_arm" "$tempRoot\bin\HostX86\arm"
+
+Write-Host "Rearranging amd64$BuildType"
+New-Item -ItemType Directory -Path "$tempRoot\bin\HostX64" | Out-Null
+Move-Item "$DropRoot\binaries.amd64$BuildType\bin\amd64" "$tempRoot\bin\HostX64\x64"
+Move-Item "$DropRoot\binaries.amd64$BuildType\bin\amd64_x86" "$tempRoot\bin\HostX64\x86"
+Move-Item "$DropRoot\binaries.amd64$BuildType\bin\amd64_arm" "$tempRoot\bin\HostX64\arm"
+
+# Only copy files and directories that already exist in the VS installation.
+Write-Host "Rearranging inc, lib"
+New-Item -ItemType Directory -Path "$tempRoot\lib" | Out-Null
+Move-Item "$DropRoot\binaries.x86$BuildType\inc" "$tempRoot\include"
+Move-Item "$DropRoot\binaries.x86$BuildType\lib\i386" "$tempRoot\lib\x86"
+Move-Item "$DropRoot\binaries.amd64$BuildType\lib\amd64" "$tempRoot\lib\x64"
+
+Write-Host "Rearranging atlmfc"
+New-Item -ItemType Directory -Path "$tempRoot\atlmfc" | Out-Null
+New-Item -ItemType Directory -Path "$tempRoot\atlmfc\lib" | Out-Null
+Move-Item "$DropRoot\binaries.x86$BuildType\atlmfc\include" "$tempRoot\atlmfc\include"
+Move-Item "$DropRoot\binaries.x86$BuildType\atlmfc\lib\i386" "$tempRoot\atlmfc\lib\x86"
+Move-Item "$DropRoot\binaries.amd64$BuildType\atlmfc\lib\amd64" "$tempRoot\atlmfc\lib\x64"
+
+$toolsets = Get-ChildItem -Path $MSVCRoot -Directory | Sort-Object -Descending
+if ($toolsets.Length -eq 0) {
+    throw "Could not find Visual Studio toolset!"
+}
+
+Write-Host "Found toolsets:`n$($toolsets -join `"`n`")`n"
+$selectedToolset = $toolsets[0]
+Write-Host "Using toolset: $selectedToolset"
+for ($idx = 1; $idx -lt $toolsets.Length; $idx++) {
+    $badToolset = $toolsets[$idx]
+    Write-Host "Deleting toolset: $badToolset"
+    Remove-Item $badToolset -Recurse -Force
+}
+
+Write-Host "Deploying $tempRoot => $selectedToolset"
+Copy-Item "$tempRoot\*" $selectedToolset -Recurse -Force
+Write-Host "Deleting $DropRoot..."
+Remove-Item $DropRoot -Recurse -Force
+Write-Host "Done!"

From 0e80327652eed0fd50d14f7a71103c2e6c8294ee Mon Sep 17 00:00:00 2001
From: Billy Robert O'Neal III <bion@microsoft.com>
Date: Wed, 23 Sep 2020 20:03:18 -0700
Subject: [PATCH 4/6] Merge.

---
 scripts/azure-pipelines/windows-unstable/job.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/azure-pipelines/windows-unstable/job.yml b/scripts/azure-pipelines/windows-unstable/job.yml
index 8697dfe358cb1b..84e3cceb55c5de 100644
--- a/scripts/azure-pipelines/windows-unstable/job.yml
+++ b/scripts/azure-pipelines/windows-unstable/job.yml
@@ -74,7 +74,7 @@ jobs:
     inputs:
       failOnStderr: true
       filePath: 'scripts/azure-pipelines/test-modified-ports.ps1'
-      arguments: '-Triplet ${{ parameters.triplet }} -BuildReason $(Build.Reason) -WorkingRoot ${{ variables.WORKING_ROOT }} -ArtifactsDirectory $(System.ArtifactsDirectory)'
+      arguments: '-Triplet ${{ parameters.triplet }} -BuildReason $(Build.Reason) -WorkingRoot ${{ variables.WORKING_ROOT }} -ArtifactStagingDirectory $(Build.ArtifactStagingDirectory)'
       pwsh: true
   - task: PowerShell@2
     displayName: 'Report on Disk Space After Build'
@@ -85,6 +85,6 @@ jobs:
   - task: PublishBuildArtifacts@1
     displayName: 'Publish Artifact: failure logs for ${{ parameters.triplet }}'
     inputs:
-      PathtoPublish: '$(System.ArtifactsDirectory)\failure-logs'
+      PathtoPublish: '$(Build.ArtifactStagingDirectory)\failure-logs'
       ArtifactName: 'failure logs for ${{ parameters.triplet }}'
     condition: failed()

From 5ba67230d17371733a0ec714b41f0382b38ebb10 Mon Sep 17 00:00:00 2001
From: Billy Robert O'Neal III <bion@microsoft.com>
Date: Mon, 28 Sep 2020 13:26:13 -0700
Subject: [PATCH 5/6] Avoid clobbering queue variables.

---
 scripts/azure-pipelines/windows-unstable/azure-pipelines.yml | 3 ---
 scripts/azure-pipelines/windows-unstable/job.yml             | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml b/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
index 4c238f56fea6a1..189ab31acdd9c6 100644
--- a/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
+++ b/scripts/azure-pipelines/windows-unstable/azure-pipelines.yml
@@ -3,12 +3,9 @@
 #
 variables:
   unstable-pool: 'VcpkgUnstable-2020-09-01'
-  MSVCBranchName: 'master'
-  DropBuildNumber: ''
 
 jobs:
 - template: job.yml
   parameters:
     triplet: x64-windows
     jobName: x64_windows
-    poolName: $(unstable-pool)
diff --git a/scripts/azure-pipelines/windows-unstable/job.yml b/scripts/azure-pipelines/windows-unstable/job.yml
index 84e3cceb55c5de..16ea4341f0ea20 100644
--- a/scripts/azure-pipelines/windows-unstable/job.yml
+++ b/scripts/azure-pipelines/windows-unstable/job.yml
@@ -5,7 +5,7 @@
 jobs:
 - job: ${{ parameters.jobName }}
   pool:
-    name: ${{ parameters.poolName }}
+    name: variables['unstable-pool']
   workspace:
     clean: resources
   timeoutInMinutes: 1440 # 1 day

From 43c43972edadae30cee8793ea6f71f8cb890f301 Mon Sep 17 00:00:00 2001
From: Billy Robert O'Neal III <bion@microsoft.com>
Date: Mon, 28 Sep 2020 13:28:50 -0700
Subject: [PATCH 6/6] Try that again.

---
 scripts/azure-pipelines/windows-unstable/job.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/azure-pipelines/windows-unstable/job.yml b/scripts/azure-pipelines/windows-unstable/job.yml
index 16ea4341f0ea20..c2eced1795c20b 100644
--- a/scripts/azure-pipelines/windows-unstable/job.yml
+++ b/scripts/azure-pipelines/windows-unstable/job.yml
@@ -5,7 +5,7 @@
 jobs:
 - job: ${{ parameters.jobName }}
   pool:
-    name: variables['unstable-pool']
+    name: $(unstable-pool)
   workspace:
     clean: resources
   timeoutInMinutes: 1440 # 1 day