Merge branch 'main' of https://github.com/dotnet/runtime into unroll-startswith

# Conflicts:
#	src/libraries/System.Private.CoreLib/src/System/String.Comparison.cs

Author: EgorBo

.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "coverlet.console": {
-      "version": "3.1.0",
+      "version": "3.1.2",
       "commands": [
         "coverlet"
       ]
@@ -15,7 +15,7 @@
       ]
     },
     "microsoft.dotnet.xharness.cli": {
-      "version": "1.0.0-prerelease.22101.2",
+      "version": "1.0.0-prerelease.22108.1",
       "commands": [
         "xharness"
       ]

.github/workflows/backport.yml

@@ -22,7 +22,7 @@ jobs:
           if (context.eventName !== "issue_comment") throw "Error: This action only works on issue_comment events.";
 
           // extract the target branch name from the trigger phrase containing these characters: a-z, A-Z, digits, forward slash, dot, hyphen, underscore
-          const regex = /\/backport to ([a-zA-Z\d\/\.\-\_]+)/;
+          const regex = /^\/backport to ([a-zA-Z\d\/\.\-\_]+)/;
           target_branch = regex.exec(context.payload.comment.body);
           if (target_branch == null) throw "Error: No backport branch found in the trigger phrase.";
 

THIRD-PARTY-NOTICES.TXT

@@ -1026,3 +1026,25 @@ a. No trademark or patent rights held by Affirmer are waived, abandoned, surrend
 b. Affirmer offers the Work as-is and makes no representations or warranties of any kind concerning the Work, express, implied, statutory or otherwise, including without limitation warranties of title, merchantability, fitness for a particular purpose, non infringement, or the absence of latent or other defects, accuracy, or the present or absence of errors, whether or not discoverable, all to the greatest extent permissible under applicable law.
 c. Affirmer disclaims responsibility for clearing rights of other persons that may apply to the Work or any use thereof, including without limitation any person's Copyright and Related Rights in the Work. Further, Affirmer disclaims responsibility for obtaining any necessary consents, permissions or other rights required for any use of the Work.
 d. Affirmer understands and acknowledges that Creative Commons is not a party to this document and has no duty or obligation with respect to this CC0 or use of the Work.
+
+
+License notice for FastFloat algorithm
+-------------------------------------
+MIT License
+Copyright (c) 2021 csFastFloat authors
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+

docs/design/coreclr/botr/clr-abi.md

@@ -752,3 +752,43 @@ The return value is handled as follows:
 4. All other cases require the use of a return buffer, through which the value is returned.
 
 In addition, there is a guarantee that if a return buffer is used a value is stored there only upon ordinary exit from the method. The buffer is not allowed to be used for temporary storage within the method and its contents will be unaltered if an exception occurs while executing the method.
+
+# Control Flow Guard (CFG) support on Windows
+
+Control Flow Guard (CFG) is a security mitigation available in Windows.
+When CFG is enabled, the operating system maintains data structures that can be used to verify whether an address is to be considered a valid indirect call target.
+This mechanism is exposed through two different helper functions, each with different characteristics.
+
+The first mechanism is a validator that takes the target address as an argument and fails fast if the address is not an expected indirect call target; otherwise, it does nothing and returns.
+The second mechanism is a dispatcher that takes the target address in a non-standard register; on successful validation of the address, it jumps directly to the target function.
+Windows makes the dispatcher available only on ARM64 and x64, while the validator is available on all platforms.
+However, the JIT supports CFG only on ARM64 and x64, with CFG by default being disabled for these platforms.
+The expected use of the CFG feature is for NativeAOT scenarios that are running in constrained environments where CFG is required.
+
+The helpers are exposed to the JIT as standard JIT helpers `CORINFO_HELP_VALIDATE_INDIRECT_CALL` and `CORINFO_HELP_DISPATCH_INDIRECT_CALL`.
+
+To use the validator the JIT expands indirect calls into a call to the validator followed by a call to the validated address.
+For the dispatcher the JIT will transform calls to pass the target along but otherwise set up the call as normal.
+
+Note that "indirect call" here refers to any call that is not to an immediate (in the instruction stream) address.
+For example, even direct calls may emit indirect call instructions in JIT codegen due to e.g. tiering or if they have not been compiled yet; these are expanded with the CFG mechanism as well.
+
+The next sections describe the calling convention that the JIT expects from these helpers.
+
+## CFG details for ARM64
+
+On ARM64, `CORINFO_HELP_VALIDATE_INDIRECT_CALL` takes the call address in `x15`.
+In addition to the usual registers it preserves all float registers, `x0`-`x8` and `x15`.
+
+`CORINFO_HELP_DISPATCH_INDIRECT_CALL` takes the call address in `x9`.
+The JIT does not use the dispatch helper by default due to worse branch predictor performance.
+Therefore it will expand all indirect calls via the validation helper and a manual call.
+
+## CFG details for x64
+
+On x64, `CORINFO_HELP_VALIDATE_INDIRECT_CALL` takes the call address in `rcx`.
+In addition to the usual registers it also preserves all float registers and `rcx` and `r10`; furthermore, shadow stack space is not required to be allocated.
+
+`CORINFO_HELP_DISPATCH_INDIRECT_CALL` takes the call address in `rax` and it reserves the right to use and trash `r10` and `r11`.
+The JIT uses the dispatch helper on x64 whenever possible as it is expected that the code size benefits outweighs the less accurate branch prediction.
+However, note that the use of `r11` in the dispatcher makes it incompatible with VSD calls where the JIT must fall back to the validator and a manual call.

docs/design/coreclr/botr/readytorun-format.md

@@ -66,8 +66,9 @@ The limitations of the current format are:
 
 # Structures
 
-The structures and accompanying constants are defined in the [readytorun.h]
-(https://github.com/dotnet/runtime/blob/main/src/coreclr/inc/readytorun.h) header file.
+The structures and accompanying constants are defined in the
+[readytorun.h](https://github.com/dotnet/runtime/blob/main/src/coreclr/inc/readytorun.h)
+header file.
 Basically the entire R2R executable image is addressed through the READYTORUN_HEADER singleton
 pointed to by the well-known export RTR_HEADER in the export section of the native executable
 envelope.

docs/design/specs/Ecma-335-Augments.md

@@ -453,7 +453,7 @@ https://www.ecma-international.org/publications-and-standards/standards/ecma-335
 
 (Add second paragraph)
 
-Static interface methods may be marked as virtual. Valid object types implementing such interfaces shall provide implementations
+Static interface methods may be marked as virtual. Valid object types implementing such interfaces may provide implementations
 for these methods by means of Method Implementations (II.15.1.4). Polymorphic behavior of calls to these methods is facilitated
 by the constrained. call IL instruction where the constrained. prefix specifies the type to use for lookup of the static interface
 method.
@@ -531,7 +531,6 @@ or static method actually implemented directly on the type.
 (Add to the end of the 1st paragraph)
 
 Interfaces may define static virtual methods that get resolved at runtime based on actual types involved.
-These static virtual methods must be marked as abstract in the defining interfaces.
 
 ### II.12.2 Implementing virtual methods on interfaces
 
@@ -754,7 +753,7 @@ the call itself doesn't involve any instance or `this` pointer.
 (Edit bulleted section "This contains informative text only" starting at the bottom of page
 233):
 
-Edit section *7.b*: Static | Virtual | !Abstract
+Remove section *7.b*: ~~Static | Virtual~~
 
 (Add new section 41 after the last section 40:)
 

docs/workflow/building/coreclr/nativeaot.md

@@ -18,10 +18,12 @@ The AOT compiler typically takes the app, core libraries, and framework librarie
 
 The executable looks like a native executable, in the sense that it can be debugged with native debuggers and have full-fidelity access to locals, and stepping information.
 
+The compiler also has a mode where each managed assembly can be compiled into a separate object file. The object files are later linked into a single executable using the platform linker. This mode is mostly used in testing (it's faster to compile this way because we don't need to recompiling the same code from e.g. CoreLib). It's not a shipping configuration and has many problems (requires exactly matching compilation settings, forfeits many optimizations, and has trouble around cross-module generic virtual method implementations).
+
 ## Building
 
 - [Install pre-requisites](../../README.md#build-requirements)
-- Run `build[.cmd|.sh] clr+libs -rc [Debug|Release] -lc Release` from the repo root. This will restore nuget packages required for building and build the parts of the repo required for general CoreCLR development. Alternatively, instead of specifying `clr+libs`, you can specify `clr.jit+clr.tools+clr.nativeaotlibs+clr.nativeaotruntime+libs` which is more targeted and builds faster. Replace `clr.jit` with `clr.alljits` if you need to crosscompile.
+- Run `build[.cmd|.sh] clr+libs -rc [Debug|Release] -lc Release` from the repo root. This will restore nuget packages required for building and build the parts of the repo required for general CoreCLR development. Alternatively, instead of specifying `clr+libs`, you can specify `clr.alljits+clr.tools+clr.nativeaotlibs+clr.nativeaotruntime+libs` which is more targeted and builds faster.
 - [NOT PORTED OVER YET] The build will place the toolchain packages at `artifacts\packages\[Debug|Release]\Shipping`. To publish your project using these packages:
    - [NOT PORTED OVER YET] Add the package directory to your `nuget.config` file. For example, replace `dotnet-experimental` line in `samples\HelloWorld\nuget.config` with `<add key="local" value="C:\runtimelab\artifacts\packages\Debug\Shipping" />`
    - [NOT PORTED OVER YET] Run `dotnet publish --packages pkg -r [win-x64|linux-x64|osx-64] -c [Debug|Release]` to publish your project. `--packages pkg` option restores the package into a local directory that is easy to cleanup once you are done. It avoids polluting the global nuget cache with your locally built dev package.
@@ -65,15 +67,12 @@ To run all the tests that got built, run `src\tests\run.cmd runnativeaottests [D
 
 To run an individual test (after it was built), navigate to the `artifacts\tests\coreclr\[Windows|Linux|OSX[.x64.[Debug|Release]\$path_to_test` directory. `$path_to_test` matches the subtree of `src\tests`. You should see a `[.cmd|.sh]` file there. This file is a script that will compile and launch the individual test for you. Before invoking the script, set the following environment variables:
 
-* CORE_ROOT=$repo_root\artifacts\tests\coreclr\[Windows|Linux|OSX[.x64.[Debug|Release]\Tests\Core_Root
-* RunNativeAot=1
-* __TestDotNetCmd=$repo_root\dotnet[.cmd|.sh]
+* CORE_ROOT=$repo_root\artifacts\tests\coreclr\[Windows|Linux|OSX].x64.[Debug|Release]\Tests\Core_Root
+* CLRCustomTestLauncher=$repo_root\src\tests\Common\scripts\nativeaottest[.cmd|.sh]
 
 `$repo_root` is the root of your clone of the repo.
 
-By default the test suite will delete the build artifacts (Native AOT images and response files) if the test compiled successfully. If you want to keep these files instead of deleting them after test run, set the following environment variables and make sure you'll have enough disk space (tens of MB per test):
-
-* CLRTestNoCleanup=1
+Sometimes it's handy to be able to rebuild the managed test manually or run the compilation under a debugger. A response file that was used to invoke the ahead of time compiler can be found in `$repo_root\artifacts\tests\coreclr\obj\[Windows|Linux|OSX].x64.[Debug|Release]\Managed`.
 
 For more advanced scenarios, look for at [Building Test Subsets](../../testing/coreclr/windows-test-instructions.md#building-test-subsets) and [Generating Core_Root](../../testing/coreclr/windows-test-instructions.md#generating-core_root)
 

docs/workflow/testing/libraries/testing-wasm.md

@@ -98,9 +98,9 @@ The following shows how to run tests for a specific library
 
 ### Passing arguments to xharness
 
-- `$(WasmXHarnessArgs)` - xharness command arguments
+- `$(WasmXHarnessArgsCli)` - xharness command arguments
 
-    Example: `WasmXHarnessArgs="--set-web-server-http-env=DOTNET_TEST_WEBSOCKETHOST"` -> becomes `dotnet xharness wasm test --set-web-server-http-env=DOTNET_TEST_WEBSOCKETHOST`
+    Example: `WasmXHarnessArgsCli="--set-web-server-http-env=DOTNET_TEST_WEBSOCKETHOST"` -> becomes `dotnet xharness wasm test --set-web-server-http-env=DOTNET_TEST_WEBSOCKETHOST`
 
 - `$(WasmXHarnessMonoArgs)` - arguments and variables for mono
 

eng/CodeAnalysis.src.globalconfig

@@ -1539,6 +1539,9 @@ dotnet_diagnostic.IDE0160.severity = silent
 # IDE0161: Convert to file-scoped namespace
 dotnet_diagnostic.IDE0161.severity = silent
 
+# IDE0190: Null check can be simplified
+dotnet_diagnostic.IDE0190.severity = suggestion
+
 # IDE1005: Delegate invocation can be simplified.
 dotnet_diagnostic.IDE1005.severity = suggestion
 

eng/CodeAnalysis.test.globalconfig

@@ -1536,6 +1536,9 @@ dotnet_diagnostic.IDE0160.severity = silent
 # IDE0161: Convert to file-scoped namespace
 dotnet_diagnostic.IDE0161.severity = silent
 
+# IDE0190: Null check can be simplified
+dotnet_diagnostic.IDE0190.severity = silent
+
 # IDE1005: Delegate invocation can be simplified.
 dotnet_diagnostic.IDE1005.severity = silent