Add some more context to the "unable to find CC toolchain" error.

PiperOrigin-RevId: 494161159 Change-Id: I3daca0adfa3fb392cb9fcd4d477a6150ee279199
bazelbuild · Dec 9, 2022 · 7312060 · 7312060
1 parent 62b0509
commit 7312060
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Showing 2 changed files with 11 additions and 3 deletions.
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/BUILD b/src/main/java/com/google/devtools/build/lib/rules/cpp/BUILD
@@ -66,6 +66,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/analysis:make_variable_supplier",
         "//src/main/java/com/google/devtools/build/lib/analysis:package_specification_provider",
         "//src/main/java/com/google/devtools/build/lib/analysis:platform_configuration",
+        "//src/main/java/com/google/devtools/build/lib/analysis:resolved_toolchain_context",
         "//src/main/java/com/google/devtools/build/lib/analysis:rule_definition_environment",
         "//src/main/java/com/google/devtools/build/lib/analysis:starlark/args",
         "//src/main/java/com/google/devtools/build/lib/analysis:starlark/starlark_api_provider",

diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppHelper.java
@@ -35,6 +35,7 @@
 import com.google.devtools.build.lib.analysis.AnalysisUtils;
 import com.google.devtools.build.lib.analysis.Expander;
 import com.google.devtools.build.lib.analysis.FileProvider;
+import com.google.devtools.build.lib.analysis.ResolvedToolchainContext;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.RuleErrorConsumer;
@@ -373,11 +374,17 @@ public static Label getToolchainTypeFromRuleClass(RuleContext ruleContext) {
 
   private static CcToolchainProvider getToolchainFromPlatformConstraints(
       RuleContext ruleContext, Label toolchainType) throws RuleErrorException {
-    ToolchainInfo toolchainInfo = ruleContext.getToolchainContext().forToolchainType(toolchainType);
+    ResolvedToolchainContext toolchainContext = ruleContext.getToolchainContext();
+    ToolchainInfo toolchainInfo = toolchainContext.forToolchainType(toolchainType);
     if (toolchainInfo == null) {
       throw ruleContext.throwWithRuleError(
-          "Unable to find a CC toolchain using toolchain resolution. Did you properly set"
-              + " --platforms?");
+          String.format(
+              "Unable to find a CC toolchain using toolchain resolution"
+                  + " (target %s, target platform %s, exec platform %s)."
+                  + " Did you properly set --platforms?",
+              ruleContext.getLabel(),
+              toolchainContext.targetPlatform().label(),
+              toolchainContext.executionPlatform().label()));
     }
     try {
       return (CcToolchainProvider) toolchainInfo.getValue("cc");