Add ARM64EC runtime test coverage

azure-pipelines.yml

@@ -11,16 +11,17 @@ pr:
 
 stages:
   - stage: Code_Format
+    dependsOn: []
     displayName: 'Code Format'
     pool:
       name: ${{ variables.poolName }}
       demands: ${{ variables.poolDemands }}
     jobs:
       - template: azure-devops/format-validation.yml
 
-  - stage: Early_Build_x64
+  - stage: Build_x64
     dependsOn: []
-    displayName: 'Early Build x64'
+    displayName: 'Build x64'
     pool:
       name: ${{ variables.poolName }}
       demands: ${{ variables.poolDemands }}
@@ -35,9 +36,9 @@ stages:
           numShards: 1
           skipTesting: true
 
-  - stage: Early_Build_x86
+  - stage: Build_x86
     dependsOn: []
-    displayName: 'Early Build x86'
+    displayName: 'Build x86'
     pool:
       name: ${{ variables.poolName }}
       demands: ${{ variables.poolDemands }}
@@ -52,9 +53,9 @@ stages:
           numShards: 1
           skipTesting: true
 
-  - stage: Early_Build_ARM64
+  - stage: Build_ARM64_Cross
     dependsOn: []
-    displayName: 'Early Build ARM64'
+    displayName: 'Build ARM64 (Cross)'
     pool:
       name: ${{ variables.poolName }}
       demands: ${{ variables.poolDemands }}
@@ -69,9 +70,9 @@ stages:
           numShards: 1
           skipTesting: true
 
-  - stage: Early_Build_ARM64EC
+  - stage: Build_ARM64EC_Cross
     dependsOn: []
-    displayName: 'Early Build ARM64EC'
+    displayName: 'Build ARM64EC (Cross)'
     pool:
       name: ${{ variables.poolName }}
       demands: ${{ variables.poolDemands }}
@@ -86,14 +87,33 @@ stages:
           numShards: 1
           skipTesting: true
 
-  - stage: Build_And_Test_x64
+  # This ARM64-native build will detect problems with the ARM64 pool as early as possible.
+  # The stage dependencies are structured to optimize the critical path.
+  - stage: Build_ARM64_Native
+    dependsOn: []
+    displayName: 'Build ARM64 (Native)'
+    pool:
+      name: ${{ variables.arm64PoolName }}
+      demands: ${{ variables.poolDemands }}
+    jobs:
+      - template: azure-devops/build-and-test.yml
+        parameters:
+          hostArch: arm64
+          targetArch: arm64
+          targetPlatform: arm64
+          analyzeBuild: true
+          buildBenchmarks: true
+          numShards: 1
+          skipTesting: true
+
+  - stage: Test_x64
     dependsOn:
       - Code_Format
-      - Early_Build_x64
-      - Early_Build_x86
-      - Early_Build_ARM64
-      - Early_Build_ARM64EC
-    displayName: 'Build and Test x64'
+      - Build_x64
+      - Build_x86
+      - Build_ARM64_Cross
+      - Build_ARM64EC_Cross
+    displayName: 'Test x64'
     pool:
       name: ${{ variables.poolName }}
       demands: ${{ variables.poolDemands }}
@@ -104,9 +124,9 @@ stages:
           targetArch: x64
           targetPlatform: x64
 
-  - stage: Build_And_Test_x86
-    dependsOn: Build_And_Test_x64
-    displayName: 'Build and Test x86'
+  - stage: Test_x86
+    dependsOn: Test_x64
+    displayName: 'Test x86'
     pool:
       name: ${{ variables.poolName }}
       demands: ${{ variables.poolDemands }}
@@ -117,9 +137,11 @@ stages:
           targetArch: x86
           targetPlatform: x86
 
-  - stage: Build_And_Test_ARM64
-    dependsOn: Build_And_Test_x64
-    displayName: 'Build and Test ARM64'
+  - stage: Test_ARM64
+    dependsOn:
+      - Build_ARM64_Native
+      - Test_x64
+    displayName: 'Test ARM64'
     pool:
       name: ${{ variables.arm64PoolName }}
       demands: ${{ variables.poolDemands }}
@@ -131,16 +153,18 @@ stages:
           targetPlatform: arm64
           numShards: 10
 
-  - stage: Build_And_Test_ARM64EC
-    dependsOn: Build_And_Test_x64
-    displayName: 'Build and Test ARM64EC'
+  - stage: Test_ARM64EC
+    dependsOn:
+      - Build_ARM64_Native
+      - Test_x64
+    displayName: 'Test ARM64EC'
     pool:
-      name: ${{ variables.poolName }}
+      name: ${{ variables.arm64PoolName }}
       demands: ${{ variables.poolDemands }}
     jobs:
       - template: azure-devops/build-and-test.yml
         parameters:
-          hostArch: x64
+          hostArch: arm64
           targetArch: arm64
           targetPlatform: arm64ec
-          testsBuildOnly: true
+          numShards: 10

tests/std/include/test_header_units_and_modules.hpp

@@ -858,7 +858,9 @@ __declspec(dllexport) void test_stacktrace() { // export test_stacktrace to have
         desc.resize(pos);
     }
 
+#ifndef _M_ARM64EC // TRANSITION, GH-5830
     assert(desc == "test_stacktrace");
+#endif // ^^^ no workaround ^^^
 }
 #endif // TEST_STANDARD >= 23
 

tests/std/tests/Dev09_158457_tr1_mem_fn_calling_conventions/test.cpp

@@ -136,7 +136,7 @@ const int free_correct   = 444343; // x86 ijw
 const int member_correct = 2111121; // x86 pure
 const int free_correct   = 433343; // x86 pure
 #endif
-#elif defined(_M_X64)
+#elif defined(_M_X64) && !defined(_M_ARM64EC)
 #if !defined(_M_CEE)
 const int member_correct = 2211112; // x64 native
 const int free_correct   = 433334; // x64 native
@@ -149,14 +149,14 @@ const int free_correct   = 433343; // x64 pure
 #endif
 #else
 #if !defined(_M_CEE)
-const int member_correct = 2211111; // arm64 native
-const int free_correct   = 433333; // arm64 native
+const int member_correct = 2211111; // arm64/arm64ec native
+const int free_correct   = 433333; // arm64/arm64ec native
 #elif !defined(_M_CEE_PURE)
-const int member_correct = 2211121; // arm64 ijw
-const int free_correct   = 433343; // arm64 ijw
+const int member_correct = 2211121; // arm64/arm64ec ijw
+const int free_correct   = 433343; // arm64/arm64ec ijw
 #else
-const int member_correct = 2111121; // arm64 pure
-const int free_correct   = 433343; // arm64 pure
+const int member_correct = 2111121; // arm64/arm64ec pure
+const int free_correct   = 433343; // arm64/arm64ec pure
 #endif
 #endif
 

tests/std/tests/P0811R3_midpoint_lerp/test.cpp

@@ -1049,7 +1049,7 @@ void test_gh_1917() {
         ExceptGuard except;
 
         assert(bit_cast<float_bit_type>(lerp(2e+38f, 1e+38f, 4.0f)) == bit_cast<float_bit_type>(-2e+38f));
-#ifndef _M_ARM64 // TRANSITION, GH-5685
+#if !defined(_M_ARM64) && !defined(_M_ARM64EC) // TRANSITION, GH-5685
         assert(check_feexcept(0));
 #endif // ^^^ no workaround ^^^
     }
@@ -1066,7 +1066,7 @@ void test_gh_1917() {
         RoundGuard round{FE_UPWARD};
 
         assert(bit_cast<float_bit_type>(lerp(2e+38f, 1e+38f, 4.0f)) == bit_cast<float_bit_type>(-2e+38f));
-#ifndef _M_ARM64 // TRANSITION, GH-5685
+#if !defined(_M_ARM64) && !defined(_M_ARM64EC) // TRANSITION, GH-5685
         assert(check_feexcept(0));
 #endif // ^^^ no workaround ^^^
     }
@@ -1082,7 +1082,7 @@ void test_gh_1917() {
         RoundGuard round{FE_DOWNWARD};
 
         assert(bit_cast<float_bit_type>(lerp(2e+38f, 1e+38f, 4.0f)) == bit_cast<float_bit_type>(-2e+38f));
-#ifndef _M_ARM64 // TRANSITION, GH-5685
+#if !defined(_M_ARM64) && !defined(_M_ARM64EC) // TRANSITION, GH-5685
         assert(check_feexcept(0));
 #endif // ^^^ no workaround ^^^
     }
@@ -1098,7 +1098,7 @@ void test_gh_1917() {
         RoundGuard round{FE_TOWARDZERO};
 
         assert(bit_cast<float_bit_type>(lerp(2e+38f, 1e+38f, 4.0f)) == bit_cast<float_bit_type>(-2e+38f));
-#ifndef _M_ARM64 // TRANSITION, GH-5685
+#if !defined(_M_ARM64) && !defined(_M_ARM64EC) // TRANSITION, GH-5685
         assert(check_feexcept(0));
 #endif // ^^^ no workaround ^^^
     }

tests/std/tests/P0881R7_stacktrace/test.cpp

@@ -13,7 +13,6 @@
 #include <stdexcept>
 #include <string>
 #include <string_view>
-#include <thread>
 
 #ifdef HAS_EXPORT
 #define MAYBE_EXPORT __declspec(dllexport)
@@ -309,8 +308,7 @@ void test_impl() {
 }
 
 int main() {
-#if !(defined(__clang__) && defined(_M_ARM64)) // TRANSITION, LLVM-74530
-    jthread t{test_impl};
+#if !((defined(__clang__) && defined(_M_ARM64)) || defined(_M_ARM64EC)) // TRANSITION, LLVM-74530, GH-5830
     test_impl();
-#endif
+#endif // ^^^ no workaround ^^^
 }

tests/universal_prefix.lst

@@ -1,4 +1,4 @@
 # Copyright (c) Microsoft Corporation.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-*	PM_CL="/nologo /Od /W4 /w14061 /w14242 /w14265 /w14582 /w14583 /w14587 /w14588 /w14749 /w14841 /w14842 /w15038 /w15214 /w15215 /w15216 /w15217 /w15262 /sdl /WX /D_ENABLE_STL_INTERNAL_CHECK /bigobj" PM_LINK="/MANIFEST:EMBED"
+*	PM_CL="/nologo /Od /W4 /w14061 /w14242 /w14265 /w14582 /w14583 /w14587 /w14588 /w14749 /w14841 /w14842 /w15038 /w15214 /w15215 /w15216 /w15217 /w15262 /sdl /WX /D_ENABLE_STL_INTERNAL_CHECK /bigobj" PM_LINK="/MANIFEST:EMBED /OPT:REF,NOICF"

tests/utils/stl/test/tests.py

@@ -245,6 +245,10 @@ def _handleEnvlst(self, litConfig):
                 self.compileFlags.append('--target=arm64-pc-windows-msvc')
             elif (targetArch == 'arm64ec'.casefold()):
                 self.compileFlags.append('--target=arm64ec-pc-windows-msvc')
+                # TRANSITION, GH-5825: As of Clang 20, compiling with `-fuse-ld=link` (avoiding lld-link)
+                # appears to be critically necessary for unknown reasons.
+                self.compileFlags.append('-fuse-ld=link')
+                self.linkFlags.append('/machine:arm64ec')
         elif ('nvcc'.casefold() in os.path.basename(cxx).casefold()):
             self._addCustomFeature('nvcc')