Add experimental support for putting full paths into compile actions. This is currently limited to compile actions started by the objc_* rules. Adding this because Xcode needs full paths to files embedded in the debug information if you want to debug while running in the simulator.

RELNOTES:none

--
MOS_MIGRATED_REVID=107253500

3 files changed, 52 insertions, 8 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java b/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
index 17b8f918d2..8c120e7aca 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
@@ -289,6 +289,26 @@ public final class CompilationSupport {
     }
   }
 
+  /**
+   * Adds a source file to a command line, honoring the useAbsolutePathForActions flag.
+   */
+  private CustomCommandLine.Builder addSource(CustomCommandLine.Builder commandLine,
+      ObjcConfiguration objcConfiguration, Artifact sourceFile) {
+    PathFragment sourceExecPathFragment = sourceFile.getExecPath();
+    String sourcePath = sourceExecPathFragment.getPathString();
+    if (!sourceExecPathFragment.isAbsolute() && objcConfiguration.getUseAbsolutePathsForActions()) {
+      sourcePath = objcConfiguration.getXcodeWorkspaceRoot() + "/" + sourcePath;
+    }
+    commandLine.add(sourcePath);
+    return commandLine;
+  }
+
+  private CustomCommandLine.Builder addSource(String argName, CustomCommandLine.Builder commandLine,
+      ObjcConfiguration objcConfiguration, Artifact sourceFile) {
+    commandLine.add(argName);
+    return addSource(commandLine, objcConfiguration, sourceFile);
+  }
+
   private void registerCompileAction(
       Artifact sourceFile,
       Artifact objFile,
@@ -340,11 +360,17 @@ public final class CompilationSupport {
         .add(coverageFlags.build())
         .add(objcConfiguration.getCopts())
         .add(attributes.copts())
-        .add(attributes.optionsCopts())
-        .addExecPath("-c", sourceFile)
-        .addExecPath("-o", objFile)
-        .add("-MD")
-        .addExecPath("-MF", dotdFile);
+        .add(attributes.optionsCopts());
+    PathFragment sourceExecPathFragment = sourceFile.getExecPath();
+    String sourcePath = sourceExecPathFragment.getPathString();
+    if (!sourceExecPathFragment.isAbsolute() && objcConfiguration.getUseAbsolutePathsForActions()) {
+      sourcePath = objcConfiguration.getXcodeWorkspaceRoot() + "/" + sourcePath;
+    }
+    commandLine
+      .add("-c").add(sourcePath)
+      .addExecPath("-o", objFile)
+      .add("-MD")
+      .addExecPath("-MF", dotdFile);
 
     if (moduleMap.isPresent()) {
       // -fmodule-map-file only loads the module in Xcode 7, so we add the module maps's directory
@@ -429,8 +455,8 @@ public final class CompilationSupport {
     commandLine
       .add("-Onone")
       .add("-module-name").add(getModuleName())
-      .add("-parse-as-library")
-      .addExecPath("-primary-file", sourceFile)
+      .add("-parse-as-library");
+    addSource("-primary-file", commandLine, objcConfiguration, sourceFile)
       .addExecPaths(otherSwiftSources)
       .addExecPath("-o", objFile)
       .addExecPath("-emit-module-path", intermediateArtifacts.swiftModuleFile(sourceFile))
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCommandLineOptions.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCommandLineOptions.java
index 6db3d16c96..99619bfdfb 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCommandLineOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcCommandLineOptions.java
@@ -207,6 +207,14 @@ public class ObjcCommandLineOptions extends FragmentOptions {
   public String iosSigningCertName;
 
   @Option(
+    name = "experimental_use_absolute_paths_for_actions",
+    defaultValue = "false",
+    category = "undocumented",
+    help = "If set, then all actions objc actions will be executed with absolute paths."
+  )
+  public boolean useAbsolutePathsForActions;
+
+  @Option(
     name = "xcode_override_workspace_root",
     defaultValue = "",
     category = "xcode",
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcConfiguration.java
index c5fe6c614a..57e901008f 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ObjcConfiguration.java
@@ -81,6 +81,7 @@ public class ObjcConfiguration extends BuildConfiguration.Fragment {
   @Nullable private final String signingCertName;
   @Nullable private final Path clientWorkspaceRoot;
   private final String xcodeOverrideWorkspaceRoot;
+  private final boolean useAbsolutePathsForActions;
 
   // We only load these labels if the mode which uses them is enabled. That is known as part of the
   // BuildConfiguration. This label needs to be part of a configuration because only configurations
@@ -123,6 +124,7 @@ public class ObjcConfiguration extends BuildConfiguration.Fragment {
     this.clientWorkspaceRoot = directories != null ? directories.getWorkspace() : null;
     this.signingCertName = objcOptions.iosSigningCertName;
     this.xcodeOverrideWorkspaceRoot = objcOptions.xcodeOverrideWorkspaceRoot;
+    this.useAbsolutePathsForActions = objcOptions.useAbsolutePathsForActions;
   }
 
   public Map<String, String> getEnvironmentForDarwin() {
@@ -138,7 +140,7 @@ public class ObjcConfiguration extends BuildConfiguration.Fragment {
   public String getIosSdkVersion() {
     return iosSdkVersion;
   }
-  
+
   public Optional<String> getXcodeVersionOverride() {
     return xcodeVersionOverride;
   }
@@ -333,6 +335,14 @@ public class ObjcConfiguration extends BuildConfiguration.Fragment {
   }
 
   /**
+   * If true, all calls to actions are done with absolute paths instead of relative paths.
+   * Using absolute paths allows Xcode to debug and deal with blaze errors in the GUI properly.
+   */
+  public boolean getUseAbsolutePathsForActions() {
+    return this.useAbsolutePathsForActions;
+  }
+
+  /**
    * Returns the path to be used for workspace_root (and path of pbxGroup mainGroup) in xcodeproj.
    * This usually will be the absolute path of the root of Bazel client workspace or null if
    * passed-in {@link BlazeDirectories} is null or Bazel fails to find the workspace root directory.