Run the LLVM IR verifier just once in pnacl-llc.

By default, using the path inherited from llc, the verifier is run twice.
We only need it to run once right after reading the bitcode in and before
the ABI verifier runs.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3553
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/18920004

3 files changed, 29 insertions, 3 deletions

diff --git a/test/NaCl/PNaClLLC/lit.local.cfg b/test/NaCl/PNaClLLC/lit.local.cfg
new file mode 100644
index 0000000000..c6106e4746
--- /dev/null
+++ b/test/NaCl/PNaClLLC/lit.local.cfg
@@ -0,0 +1 @@
+config.suffixes = ['.ll']
diff --git a/test/NaCl/PNaClLLC/test-runs-verify.ll b/test/NaCl/PNaClLLC/test-runs-verify.ll
new file mode 100644
index 0000000000..9e7c9d32a5
--- /dev/null
+++ b/test/NaCl/PNaClLLC/test-runs-verify.ll
@@ -0,0 +1,13 @@
+; RUN: not pnacl-llc -mtriple=i386-unknown-nacl -filetype=asm %s -o - 2>&1 | FileCheck %s
+
+; Test that the Verifier pass is running in pnacl-llc.
+
+define i32 @f1(i32 %x) {
+  %y = add i32 %z, 1
+  %z = add i32 %x, 1
+  ret i32 %y
+; CHECK: Instruction does not dominate all uses!
+; CHECK-NEXT:  %z = add i32 %x, 1
+; CHECK-NEXT:  %y = add i32 %z, 1
+}
+
diff --git a/tools/pnacl-llc/pnacl-llc.cpp b/tools/pnacl-llc/pnacl-llc.cpp
index 6292001ab1..b085a0be57 100644
--- a/tools/pnacl-llc/pnacl-llc.cpp
+++ b/tools/pnacl-llc/pnacl-llc.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/ADT/Triple.h"
 #include "llvm/Analysis/NaCl.h"
+#include "llvm/Analysis/Verifier.h"
 #include "llvm/Assembly/PrintModulePass.h"
 #include "llvm/Support/DataStream.h"
 #include "llvm/Bitcode/NaCl/NaClReaderWriter.h"
@@ -428,6 +429,13 @@ static int compileModule(char **argv, LLVMContext &Context) {
   else
     PM.reset(new PassManager());
 
+  // For conformance with llc, we let the user disable LLVM IR verification with
+  // -disable-verify. Unlike llc, when LLVM IR verification is enabled we only
+  // run it once, before PNaCl ABI verification.
+  if (!NoVerify) {
+    PM->add(createVerifierPass());
+  }
+
   // Add the ABI verifier pass before the analysis and code emission passes.
   FunctionPass *FunctionVerifyPass = NULL;
   if (PNaClABIVerify) {
@@ -470,8 +478,10 @@ static int compileModule(char **argv, LLVMContext &Context) {
     ROS.SetBufferSize(1 << 20);
     formatted_raw_ostream FOS(ROS);
 
-    // Ask the target to add backend passes as necessary.
-    if (Target.addPassesToEmitFile(*PM, FOS, FileType, NoVerify)) {
+    // Ask the target to add backend passes as necessary. We explicitly ask it
+    // not to add the verifier pass because we added it earlier.
+    if (Target.addPassesToEmitFile(*PM, FOS, FileType,
+                                   /* DisableVerify */ true)) {
       errs() << argv[0] << ": target does not support generation of this"
              << " file type!\n";
       return 1;
@@ -520,7 +530,9 @@ static int compileModule(char **argv, LLVMContext &Context) {
     }
 
     // Ask the target to add backend passes as necessary.
-    if (Target.addPassesToEmitFile(*PM, FOS, FileType, NoVerify,
+    // TODO: decrease the amount of code duplication with __native_client__
+    if (Target.addPassesToEmitFile(*PM, FOS, FileType,
+                                   /* DisableVerify */ true,
                                    StartAfterID, StopAfterID)) {
       errs() << argv[0] << ": target does not support generation of this"
              << " file type!\n";