Reject @_silgen_name on globals that are not statically initialized

Author: kubamracek

include/swift/AST/DiagnosticsSIL.def

@@ -335,8 +335,8 @@ ERROR(performance_unknown_callees,none,
       "called function is not known at compile time and can have unpredictable performance", ())
 ERROR(performance_callee_unavailable,none,
       "called function is not available in this module and can have unpredictable performance", ())
-ERROR(section_attr_on_non_const_global,none,
-      "global variable must be a compile-time constant to use @_section attribute", ())
+ERROR(bad_attr_on_non_const_global,none,
+      "global variable must be a compile-time constant to use %0 attribute", (StringRef))
 NOTE(performance_called_from,none,
       "called from here", ())
 

lib/SILGen/SILGenGlobalVariable.cpp

@@ -50,6 +50,9 @@ SILGlobalVariable *SILGenModule::getSILGlobalVariable(VarDecl *gDecl,
 
   if (gDecl->getAttrs().hasAttribute<SILGenNameAttr>()) {
     silLinkage = SILLinkage::DefaultForDeclaration;
+    if (! gDecl->hasInitialValue()) {
+      forDef = NotForDefinition;
+    }
   }
 
   // Check if it is already created, and update linkage if necessary.

lib/SILOptimizer/Mandatory/PerformanceDiagnostics.cpp

@@ -477,11 +477,22 @@ class PerformanceDiagnosticsPass : public SILModuleTransform {
 
     PerformanceDiagnostics diagnoser(*module, getAnalysis<BasicCalleeAnalysis>());
 
-    // Check that @_section is only on constant globals
+    // Check that @_section, @_silgen_name is only on constant globals
     for (SILGlobalVariable &g : module->getSILGlobals()) {
-      if (!g.getStaticInitializerValue() && g.getSectionAttr())
-        module->getASTContext().Diags.diagnose(
-            g.getDecl()->getLoc(), diag::section_attr_on_non_const_global);
+      if (!g.getStaticInitializerValue()) {
+        if (g.getSectionAttr()) {
+          module->getASTContext().Diags.diagnose(
+            g.getDecl()->getLoc(), diag::bad_attr_on_non_const_global,
+            "@_section");
+        }
+
+        auto *decl = g.getDecl();
+        if (decl && g.isDefinition() && decl->getAttrs().hasAttribute<SILGenNameAttr>()) {
+          module->getASTContext().Diags.diagnose(
+            g.getDecl()->getLoc(), diag::bad_attr_on_non_const_global,
+            "@_silgen_name");
+        }
+      }
     }
 
     bool annotatedFunctionsFound = false;

test/IRGen/silgen_name_non_const.swift

@@ -0,0 +1,15 @@
+// RUN: %target-swift-frontend -enable-experimental-feature SymbolLinkageMarkers -parse-as-library -emit-sil %s -o /dev/null -verify
+
+// REQUIRES: swift_in_compiler
+
+@_silgen_name("g0") var g0: Int = 1
+@_silgen_name("g1") var g1: (Int, Int) = (1, 2)
+@_silgen_name("g2") var g2: [Int] = [1, 2, 3] // expected-error {{global variable must be a compile-time constant to use @_silgen_name attribute}}
+@_silgen_name("g3") var g3: [Int:Int] = [:] // expected-error {{global variable must be a compile-time constant to use @_silgen_name attribute}}
+@_silgen_name("g4") var g4: UInt = 42
+@_silgen_name("g5") var g5: String = "hello" // expected-error {{global variable must be a compile-time constant to use @_silgen_name attribute}}
+@_silgen_name("g6") var g6: Any = 1 // expected-error {{global variable must be a compile-time constant to use @_silgen_name attribute}}
+@_silgen_name("g7") var g7: UInt8 = 42
+@_silgen_name("g8") var g8: Int = 5 * 5
+
+@_silgen_name("fwd1") var fwd1: Int