[PATCH] D38042: EmitAssemblyHelper: CodeGenOpts.DisableLLVMOpts should not overrule CodeGenOpts.VerifyModule.

[Adrian Prantl via Phabricator via cfe-commits]

aprantl created this revision.

This patch fixes a regression introduced by r290392 (https://reviews.llvm.org/D28047 — Make '-disable-llvm-optzns' an alias for '-disable-llvm-passes'.)

After r290392, CodeGenOpts.DisableLLVMOpts implicitly disables CodeGenOpts.VerifyModule, because the Verifier also happens to be implemented as an LLVM pass. This new behavior is undesirable because the Verifier is clearly not an optimization. One use-case where this is relevant is when using clang to compile bitcode; we don't want the compiler to crash on invalid input just because -disable-llvm-optzns is used.


https://reviews.llvm.org/D38042

Files:
  lib/CodeGen/BackendUtil.cpp
  test/CodeGen/verify-debuginfo.ll


Index: test/CodeGen/verify-debuginfo.ll
===================================================================
--- /dev/null
+++ test/CodeGen/verify-debuginfo.ll
@@ -0,0 +1,17 @@
+; REQUIRES: x86-registered-target
+; RUN: %clang_cc1 -triple i386-apple-darwin -disable-llvm-optzns -S %s -o - 2>&1 \
+; RUN:   | FileCheck %s
+; CHECK: invalid global variable ref
+; CHECK: warning: ignoring invalid debug info in {{.*}}.ll
+
+ at global = common global i32 0, align 4, !dbg !2
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!5, !6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "adrian", emissionKind: FullDebug, globals: !{!3})
+!1 = !DIFile(filename: "broken.c", directory: "/")
+!2 = !DIGlobalVariableExpression(var: !3, expr: !DIExpression())
+!3 = !DIGlobalVariable(name: "g", scope: !0, file: !1, line: 1, type: !1, isLocal: false, isDefinition: true)
+!5 = !{i32 2, !"Dwarf Version", i32 4}
+!6 = !{i32 1, !"Debug Info Version", i32 3}
Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -461,8 +461,16 @@
                                       legacy::FunctionPassManager &FPM) {
   // Handle disabling of all LLVM passes, where we want to preserve the
   // internal module before any optimization.
-  if (CodeGenOpts.DisableLLVMPasses)
+  if (CodeGenOpts.DisableLLVMPasses) {
+    if (CodeGenOpts.VerifyModule) {
+      ModulePassManager MPM;
+      MPM.addPass(VerifierPass(false));
+      ModuleAnalysisManager MAM;
+      MAM.registerPass([&] { return VerifierAnalysis(); });
+      MPM.run(*TheModule, MAM);
+    }
     return;
+  }
 
   // Figure out TargetLibraryInfo.  This needs to be added to MPM and FPM
   // manually (and not via PMBuilder), since some passes (eg. InstrProfiling)


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D38042.115854.patch
Type: text/x-patch
Size: 1843 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20170919/6c3a94bb/attachment.bin>