Merge main to feature/flat_map

CMakeLists.txt

@@ -1,13 +1,13 @@
 # Copyright (c) Microsoft Corporation.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-cmake_minimum_required(VERSION 3.31.0)
+cmake_minimum_required(VERSION 4.1.1)
 
 set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
 project(msvc_standard_libraries LANGUAGES CXX)
 
-if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS "19.50.35503")
-    message(FATAL_ERROR "The STL must be built with MSVC Compiler 19.50 Preview 1 or later.")
+if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS "19.50.35702")
+    message(FATAL_ERROR "The STL must be built with MSVC Compiler 19.50.35702 or later.")
 endif()
 
 include(CheckCXXSourceCompiles)
@@ -112,13 +112,7 @@ endif()
 
 set(VCLIBS_DEBUG_OPTIONS "$<$<COMPILE_LANGUAGE:CXX>:/Od>")
 
-# TRANSITION: Potentially remove `/Os` if it results in speed improvements.
-# This requires benchmarking!
-# Note that in MSVC version 19.32.31328,
-# `/Os` results in a binary size difference of 102K
-# in the release DLL (a gain of 18.4%).
-# So, make certain that that tradeoff is considered when or if `/Os` is removed.
-# See GH-2108 for more info.
+# TRANSITION, GH-2108: Investigate building the STL with only /O2, not /Os.
 set(VCLIBS_RELEASE_OPTIONS "$<$<COMPILE_LANGUAGE:CXX>:/O2;/Os>")
 
 if(BUILD_TESTING)

CMakePresets.json

@@ -22,7 +22,7 @@
       },
       "condition": {
         "type": "inList",
-        "string": "$env{Platform}",
+        "string": "$env{VSCMD_ARG_TGT_ARCH}",
         "list": [
           "x64",
           ""
@@ -39,7 +39,7 @@
       },
       "condition": {
         "type": "inList",
-        "string": "$env{Platform}",
+        "string": "$env{VSCMD_ARG_TGT_ARCH}",
         "list": [
           "x86",
           ""
@@ -56,7 +56,7 @@
       },
       "condition": {
         "type": "inList",
-        "string": "$env{Platform}",
+        "string": "$env{VSCMD_ARG_TGT_ARCH}",
         "list": [
           "arm64",
           ""
@@ -76,7 +76,7 @@
       },
       "condition": {
         "type": "inList",
-        "string": "$env{Platform}",
+        "string": "$env{VSCMD_ARG_TGT_ARCH}",
         "list": [
           "arm64",
           ""

README.md

@@ -151,7 +151,7 @@ Just try to follow these rules, so we can spend more time fixing bugs and implem
     - "Windows 11 SDK (10.0.26100)" or later
     - "C++ Clang tools for Windows (20.1.8 - x64/x86)"
     - *Optional, see Note 2 below:* "MSVC v145 - C++ ARM64/ARM64EC build tools (Latest)"
-* Install [Python][] 3.13 or later.
+* Install [Python][] 3.14.0 or later.
   + Select "Add python.exe to PATH" if you want to follow the instructions below that invoke `python`.
     Otherwise, you should be familiar with alternative methods.
 
@@ -469,6 +469,32 @@ If you want to see all the other flags you can pass, run:
 out\bench\benchmark-<benchmark-name> --help
 ```
 
+## Other Useful Incantations
+
+To compile the benchmarks with additional compiler options, use the [`CXXFLAGS` environment variable][CXXFLAGS].
+Set it after configuring and building the STL, but before configuring and building the benchmarks.
+For example, to examine how the `/arch:AVX2` option affects auto-vectorization and bit algorithm intrinsics:
+
+```
+set CXXFLAGS=/arch:AVX2
+cmake -B out\bench -S benchmarks -G Ninja -DSTL_BINARY_DIR=out\x64
+cmake --build out\bench
+```
+
+To compile the benchmarks with Clang, use `-DCMAKE_CXX_COMPILER=clang-cl`:
+
+```
+cmake -B out\bench -S benchmarks -G Ninja -DSTL_BINARY_DIR=out\x64 -DCMAKE_CXX_COMPILER=clang-cl
+cmake --build out\bench
+```
+
+To run a benchmark on specific cores (e.g. P-cores vs. E-cores) and with higher priority
+(to avoid interference), use the [`start` command][start-command]:
+
+```
+start /b /wait /high /affinity 0F out\bench\benchmark-std_copy
+```
+
 # Editing And Testing The Debugger Visualizer
 
 ### Modify The Visualizer
@@ -581,3 +607,5 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 [ASan]: https://learn.microsoft.com/en-us/cpp/sanitizers/asan
 [Import Library]: /docs/import_library.md
 [VS 2026 Insiders]: https://visualstudio.microsoft.com/insiders/
+[CXXFLAGS]: https://cmake.org/cmake/help/latest/envvar/CXXFLAGS.html
+[start-command]: https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/start

azure-devops/config.yml

@@ -5,7 +5,7 @@
 
 variables:
 - name: poolName
-  value: 'StlBuild-2025-09-09T1526-Pool'
+  value: 'Stl-2025-10-14T1635-x64-Pool'
   readonly: true
 - name: poolDemands
   value: 'EnableSpotVM -equals false'

azure-devops/create-1es-hosted-pool.ps1

@@ -12,15 +12,18 @@ See https://github.com/microsoft/STL/wiki/Checklist-for-Toolset-Updates for more
 $ErrorActionPreference = 'Stop'
 
 $CurrentDate = Get-Date
+$Timestamp = $CurrentDate.ToString('yyyy-MM-ddTHHmm')
+$Arch = 'x64'
 
 $Location = 'eastus2'
 $VMSize = 'Standard_F32as_v6'
+$PoolSize = 64
 $ProtoVMName = 'PROTOTYPE'
 $ImagePublisher = 'MicrosoftWindowsServer'
 $ImageOffer = 'WindowsServer'
 $ImageSku = '2025-datacenter-azure-edition'
 
-$LogFile = '1es-hosted-pool.log'
+$LogFile = "1es-hosted-pool-$Timestamp-$Arch.log"
 $ProgressActivity = 'Preparing STL CI pool'
 $TotalProgress = 38
 $CurrentProgress = 1
@@ -82,15 +85,16 @@ Update-AzConfig `
   -Scope 'Process' >> $LogFile
 
 ####################################################################################################
-Display-ProgressBar -Status 'Setting the subscription context'
+Display-ProgressBar -Status 'Getting the subscription context'
 
-Set-AzContext `
-  -SubscriptionName 'CPP_STL_GitHub' >> $LogFile
+if ((Get-AzContext).Subscription.Name -cne 'CPP_STL_GitHub') {
+  Write-Error 'Please sign in with `Connect-AzAccount -Subscription ''CPP_STL_GitHub''` before running this script.'
+}
 
 ####################################################################################################
 Display-ProgressBar -Status 'Creating resource group'
 
-$ResourceGroupName = 'StlBuild-' + $CurrentDate.ToString('yyyy-MM-ddTHHmm')
+$ResourceGroupName = "Stl-$Timestamp-$Arch"
 
 New-AzResourceGroup `
   -Name $ResourceGroupName `
@@ -105,7 +109,7 @@ $Credential = New-Object System.Management.Automation.PSCredential ('AdminUser',
 ####################################################################################################
 Display-ProgressBar -Status 'Creating public IP address'
 
-$PublicIpAddressName = $ResourceGroupName + '-PublicIpAddress'
+$PublicIpAddressName = "$ResourceGroupName-PublicIpAddress"
 $PublicIpAddress = New-AzPublicIpAddress `
   -Name $PublicIpAddressName `
   -ResourceGroupName $ResourceGroupName `
@@ -116,7 +120,7 @@ $PublicIpAddress = New-AzPublicIpAddress `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating NAT gateway'
 
-$NatGatewayName = $ResourceGroupName + '-NatGateway'
+$NatGatewayName = "$ResourceGroupName-NatGateway"
 $NatGateway = New-AzNatGateway `
   -Name $NatGatewayName `
   -ResourceGroupName $ResourceGroupName `
@@ -128,7 +132,7 @@ $NatGateway = New-AzNatGateway `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating network security group'
 
-$NetworkSecurityGroupName = $ResourceGroupName + '-NetworkSecurity'
+$NetworkSecurityGroupName = "$ResourceGroupName-NetworkSecurity"
 $NetworkSecurityGroup = New-AzNetworkSecurityGroup `
   -Name $NetworkSecurityGroupName `
   -ResourceGroupName $ResourceGroupName `
@@ -137,10 +141,12 @@ $NetworkSecurityGroup = New-AzNetworkSecurityGroup `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating virtual network subnet config'
 
-# TRANSITION, 2025-09-30: "On September 30, 2025, default outbound access for new deployments will be retired."
+# TRANSITION, 2026-03-31: "After March 31, 2026, new virtual networks will default to using private subnets,
+# meaning that an explicit outbound method must be enabled in order to reach public endpoints on the Internet
+# and within Microsoft."
 # https://learn.microsoft.com/en-us/azure/virtual-network/ip-services/default-outbound-access
 # We're using `-DefaultOutboundAccess $false` to opt-in early.
-$SubnetName = $ResourceGroupName + '-Subnet'
+$SubnetName = "$ResourceGroupName-Subnet"
 $Subnet = New-AzVirtualNetworkSubnetConfig `
   -Name $SubnetName `
   -AddressPrefix '10.0.0.0/16' `
@@ -151,7 +157,7 @@ $Subnet = New-AzVirtualNetworkSubnetConfig `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating virtual network'
 
-$VirtualNetworkName = $ResourceGroupName + '-Network'
+$VirtualNetworkName = "$ResourceGroupName-Network"
 $VirtualNetwork = New-AzVirtualNetwork `
   -Name $VirtualNetworkName `
   -ResourceGroupName $ResourceGroupName `
@@ -162,7 +168,7 @@ $VirtualNetwork = New-AzVirtualNetwork `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating network interface'
 
-$NicName = $ResourceGroupName + '-NIC'
+$NicName = "$ResourceGroupName-NIC"
 $Nic = New-AzNetworkInterface `
   -Name $NicName `
   -ResourceGroupName $ResourceGroupName `
@@ -295,7 +301,7 @@ Set-AzVM `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating gallery'
 
-$GalleryName = 'StlBuild_' + $CurrentDate.ToString('yyyy_MM_ddTHHmm') + '_Gallery'
+$GalleryName = "$ResourceGroupName-Gallery" -replace '-', '_'
 $Gallery = New-AzGallery `
   -Location $Location `
   -ResourceGroupName $ResourceGroupName `
@@ -314,7 +320,7 @@ New-AzRoleAssignment `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating image definition'
 
-$ImageDefinitionName = $ResourceGroupName + '-ImageDefinition'
+$ImageDefinitionName = "$ResourceGroupName-ImageDefinition"
 $FeatureTrustedLaunch = @{ Name = 'SecurityType'; Value = 'TrustedLaunch'; }
 $FeatureNVMe = @{ Name = 'DiskControllerTypes'; Value = 'SCSI, NVMe'; }
 $ImageDefinitionFeatures = @($FeatureTrustedLaunch, $FeatureNVMe)
@@ -352,7 +358,7 @@ Register-AzResourceProvider `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating 1ES image'
 
-$ImageName = $ResourceGroupName + '-Image'
+$ImageName = "$ResourceGroupName-Image"
 New-AzResource `
   -Location $Location `
   -ResourceGroupName $ResourceGroupName `
@@ -364,14 +370,14 @@ New-AzResource `
 ####################################################################################################
 Display-ProgressBar -Status 'Creating 1ES Hosted Pool'
 
-$PoolName = $ResourceGroupName + '-Pool'
+$PoolName = "$ResourceGroupName-Pool"
 
 $PoolProperties = @{
   'organization' = 'https://dev.azure.com/vclibs'
   'projects' = @('STL')
   'sku' = @{ 'name' = $VMSize; 'tier' = 'StandardSSD'; 'enableSpot' = $false; }
   'images' = @(@{ 'imageName' = $ImageName; 'poolBufferPercentage' = '100'; })
-  'maxPoolSize' = 64
+  'maxPoolSize' = $PoolSize
   'agentProfile' = @{ 'type' = 'Stateless'; }
 }
 

azure-devops/provision-image.ps1

@@ -19,6 +19,16 @@ if ($Env:COMPUTERNAME -cne 'PROTOTYPE') {
   Write-Error 'You should not run provision-image.ps1 on your local machine.'
 }
 
+if ($Env:PROCESSOR_ARCHITECTURE -ceq 'AMD64') {
+  Write-Host 'Provisioning x64.'
+  $Provisioning_x64 = $true
+} elseif ($Env:PROCESSOR_ARCHITECTURE -ceq 'ARM64') {
+  Write-Host 'Provisioning ARM64.'
+  $Provisioning_x64 = $false
+} else {
+  Write-Error "Unrecognized PROCESSOR_ARCHITECTURE: '$Env:PROCESSOR_ARCHITECTURE'"
+}
+
 $VisualStudioWorkloads = @(
   'Microsoft.VisualStudio.Component.VC.ASAN',
   'Microsoft.VisualStudio.Component.VC.CLI.Support',
@@ -31,6 +41,10 @@ $VisualStudioWorkloads = @(
   'Microsoft.VisualStudio.Component.Windows11SDK.26100'
 )
 
+# https://learn.microsoft.com/en-us/visualstudio/install/visual-studio-on-arm-devices
+# "There's a single installer for both Visual Studio x64 and Visual Studio Arm64 architectures.
+# The Visual Studio Installer detects whether the system architecture is Arm64.
+# If it is, the installer downloads and installs the Arm64 version of Visual Studio."
 $VisualStudioUrl = 'https://aka.ms/vs/18/insiders/vs_Community.exe'
 $VisualStudioArgs = @('--quiet', '--norestart', '--wait', '--nocache')
 foreach ($workload in $VisualStudioWorkloads) {
@@ -39,13 +53,27 @@ foreach ($workload in $VisualStudioWorkloads) {
 }
 
 # https://github.com/PowerShell/PowerShell/releases/latest
-$PowerShellUrl = 'https://github.com/PowerShell/PowerShell/releases/download/v7.5.2/PowerShell-7.5.2-win-x64.msi'
+if ($Provisioning_x64) {
+  $PowerShellUrl = 'https://github.com/PowerShell/PowerShell/releases/download/v7.5.3/PowerShell-7.5.3-win-x64.msi'
+} else {
+  $PowerShellUrl = 'https://github.com/PowerShell/PowerShell/releases/download/v7.5.3/PowerShell-7.5.3-win-arm64.msi'
+}
 $PowerShellArgs = @('/quiet', '/norestart')
 
-$PythonUrl = 'https://www.python.org/ftp/python/3.13.7/python-3.13.7-amd64.exe'
+# https://www.python.org
+if ($Provisioning_x64) {
+  $PythonUrl = 'https://www.python.org/ftp/python/3.14.0/python-3.14.0-amd64.exe'
+} else {
+  $PythonUrl = 'https://www.python.org/ftp/python/3.14.0/python-3.14.0-arm64.exe'
+}
 $PythonArgs = @('/quiet', 'InstallAllUsers=1', 'PrependPath=1', 'CompileAll=1', 'Include_doc=0')
 
-$CudaUrl = 'https://developer.download.nvidia.com/compute/cuda/12.4.0/local_installers/cuda_12.4.0_551.61_windows.exe'
+# https://developer.nvidia.com/cuda-toolkit
+if ($Provisioning_x64) {
+  $CudaUrl = 'https://developer.download.nvidia.com/compute/cuda/12.4.0/local_installers/cuda_12.4.0_551.61_windows.exe'
+} else {
+  $CudaUrl = 'CUDA is not installed for ARM64'
+}
 $CudaArgs = @('-s', '-n')
 
 <#
@@ -91,10 +119,16 @@ Function DownloadAndInstall {
     } else {
       Write-Error "Installation failed! Exited with $exitCode."
     }
+  } catch {
+    Write-Error "Installation failed! Exception: $($_.Exception.Message)"
+  }
 
+  try {
+    # Briefly sleep before removing the installer, attempting to avoid "Access to the path '$installerPath' is denied."
+    Start-Sleep -Seconds 5
     Remove-Item -Path $installerPath
   } catch {
-    Write-Error "Installation failed! Exception: $($_.Exception.Message)"
+    Write-Error "Remove-Item failed! Exception: $($_.Exception.Message)"
   }
 }
 
@@ -104,16 +138,24 @@ Write-Host "Old PowerShell version: $($PSVersionTable.PSVersion)"
 # Skip a blank line to improve the output.
 (cmd /c ver)[1]
 
-DownloadAndInstall -Name 'PowerShell'    -Url $PowerShellUrl   -Args $PowerShellArgs
-DownloadAndInstall -Name 'Python'        -Url $PythonUrl       -Args $PythonArgs
-DownloadAndInstall -Name 'Visual Studio' -Url $VisualStudioUrl -Args $VisualStudioArgs
-DownloadAndInstall -Name 'CUDA'          -Url $CudaUrl         -Args $CudaArgs
+DownloadAndInstall   -Name 'PowerShell'    -Url $PowerShellUrl   -Args $PowerShellArgs
+DownloadAndInstall   -Name 'Python'        -Url $PythonUrl       -Args $PythonArgs
+DownloadAndInstall   -Name 'Visual Studio' -Url $VisualStudioUrl -Args $VisualStudioArgs
+if ($Provisioning_x64) {
+  DownloadAndInstall -Name 'CUDA'          -Url $CudaUrl         -Args $CudaArgs
+}
 
 Write-Host 'Setting environment variables...'
 
 # The STL's PR/CI builds are totally unrepresentative of customer usage.
 [Environment]::SetEnvironmentVariable('VSCMD_SKIP_SENDTELEMETRY', '1', 'Machine')
 
+Write-Host 'Enabling long paths...'
+
+# https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=powershell
+New-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\FileSystem' -Name 'LongPathsEnabled' `
+  -Value 1 -PropertyType DWORD -Force | Out-Null
+
 # Tell create-1es-hosted-pool.ps1 that we succeeded.
 Write-Host 'PROVISION_IMAGE_SUCCEEDED'