[PATCH] D16490: [CUDA] Die gracefully when trying to output an LLVM alias.

[Justin Lebar via llvm-commits]

jlebar created this revision.
jlebar added a reviewer: tra.
jlebar added subscribers: echristo, jhen, llvm-commits.
Herald added a subscriber: jholewinski.

Previously, we would just output "foo = bar" in the assembly, and then
ptxas would choke.  Now we die before emitting any invalid code.

We could check for aliases much earlier, e.g. during doInitialization.
But I figure it's better to emit as much code as we can and only die at
the last minute.

http://reviews.llvm.org/D16490

Files:
  lib/Target/NVPTX/NVPTXAsmPrinter.cpp
  test/CodeGen/NVPTX/alias.ll

Index: test/CodeGen/NVPTX/alias.ll
===================================================================
--- /dev/null
+++ test/CodeGen/NVPTX/alias.ll
@@ -0,0 +1,7 @@
+; RUN: not llc < %s -march=nvptx -mcpu=sm_20 2>&1 | FileCheck %s
+
+; Check that llc dies gracefully when given an alias.
+
+define i32 @a() { ret i32 0 }
+; CHECK: ERROR: Module has aliases
+ at b = internal alias i32 (), i32 ()* @a
Index: lib/Target/NVPTX/NVPTXAsmPrinter.cpp
===================================================================
--- lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -945,8 +945,16 @@
   while (!global_list.empty())
     global_list.remove(global_list.begin());
 
-  // call doFinalization
-  bool ret = AsmPrinter::doFinalization(M);
+  // Aliases are emitted during AsmPrinter::doFinalization(), so bail before
+  // then if we have any.
+  bool ret = false;
+  if (M.alias_size()) {
+    report_fatal_error("Module has aliases, which NVPTX does not support.");
+    ret = true; // error
+  }
+
+  if (!ret)
+    ret = AsmPrinter::doFinalization(M);
 
   // now we restore global variables
   for (i = 0; i < n; i++)


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