Debug Info: drop debug info via upgrading path if version number does not match.

Add a helper function getDebugInfoVersionFromModule to return the debug info
version number for a module.

"Verifier/module-flags-1.ll" checks for verification errors.
It will seg fault when calling getDebugInfoVersionFromModule because of the
incorrect format for module flags in the testing case. We make
getModuleFlagsMetadata more robust by checking for error conditions.

PR17982

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196158 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/AutoUpgrade.h b/include/llvm/AutoUpgrade.h
index b638d4f59048a1108336966338f3633bd780d848..c774782f19ec54504992c14728c4b4ea02f1ecb8 100644 (file)
--- a/include/llvm/AutoUpgrade.h
+++ b/include/llvm/AutoUpgrade.h
@@ -57,6 +57,10 @@ namespace llvm {
   /// with different address spaces: the instruction is replaced by a pair
   /// ptrtoint+inttoptr.
   Value *UpgradeBitCastExpr(unsigned Opc, Constant *C, Type *DestTy);
+
+  /// Check the debug info version number, if it is out-dated, drop the debug
+  /// info. Return true if module is modified.
+  bool UpgradeDebugInfo(Module &M);
 } // End llvm namespace
 
 #endif

diff --git a/include/llvm/DebugInfo.h b/include/llvm/DebugInfo.h
index 0ff7d856823072fa9b4b4ac9c4c3f4a85b61fa01..7c4c1123b509de6881fa40fdafa9d4e61c873dc1 100644 (file)
--- a/include/llvm/DebugInfo.h
+++ b/include/llvm/DebugInfo.h
@@ -759,6 +759,9 @@ DITypeIdentifierMap generateDITypeIdentifierMap(const NamedMDNode *CU_Nodes);
 /// Return true if module is modified.
 bool StripDebugInfo(Module &M);
 
+/// Return Debug Info Version by checking module flags.
+unsigned getDebugInfoVersionFromModule(const Module &M);
+
 /// DebugInfoFinder tries to list all debug info MDNodes used in a module. To
 /// list debug info MDNodes used by an instruction, DebugInfoFinder uses
 /// processDeclare, processValue and processLocation to handle DbgDeclareInst,

diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 20fa0f4eab1ea79fc193dfb022f9128a6891aac5..3b903cdb0906b357aabddbd753012b6bd5e09f7a 100644 (file)
--- a/lib/AsmParser/LLParser.cpp
+++ b/lib/AsmParser/LLParser.cpp
@@ -182,6 +182,8 @@ bool LLParser::ValidateEndOfModule() {
   for (Module::iterator FI = M->begin(), FE = M->end(); FI != FE; )
     UpgradeCallsToIntrinsic(FI++); // must be post-increment, as we remove
 
+  UpgradeDebugInfo(*M);
+
   return false;
 }
 

diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 2c95c920f8406787197653a103fc00c588b06a10..ce3b7d163e51ad668baa3e3b61ed241c372e7dc4 100644 (file)
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -3152,6 +3152,7 @@ error_code BitcodeReader::MaterializeModule(Module *M) {
   for (unsigned I = 0, E = InstsWithTBAATag.size(); I < E; I++)
     UpgradeInstWithTBAATag(InstsWithTBAATag[I]);
 
+  UpgradeDebugInfo(*M);
   return error_code::success();
 }
 

diff --git a/lib/IR/AutoUpgrade.cpp b/lib/IR/AutoUpgrade.cpp
index 6f79919f241d74351261ee02a76a61807b50ba5f..32cfe278c73aa68ae95d4fcef7fbd9b37aa36549 100644 (file)
--- a/lib/IR/AutoUpgrade.cpp
+++ b/lib/IR/AutoUpgrade.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/AutoUpgrade.h"
+#include "llvm/DebugInfo.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
@@ -489,3 +490,12 @@ Value *llvm::UpgradeBitCastExpr(unsigned Opc, Constant *C, Type *DestTy) {
 
   return 0;
 }
+
+/// Check the debug info version number, if it is out-dated, drop the debug
+/// info. Return true if module is modified.
+bool llvm::UpgradeDebugInfo(Module &M) {
+  if (getDebugInfoVersionFromModule(M) == DEBUG_METADATA_VERSION)
+    return false;
+
+  return StripDebugInfo(M);
+}

diff --git a/lib/IR/DebugInfo.cpp b/lib/IR/DebugInfo.cpp
index 0c262024ff08186b53fab9088fa3f884b9a0855e..68015b759a733b797b358e28f5684ef460e6a924 100644 (file)
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -1477,3 +1477,11 @@ bool llvm::StripDebugInfo(Module &M) {
 
   return Changed;
 }
+
+/// Return Debug Info Version by checking module flags.
+unsigned llvm::getDebugInfoVersionFromModule(const Module &M) {
+  Value *Val = M.getModuleFlag("Debug Info Version");
+  if (!Val)
+    return 0;
+  return cast<ConstantInt>(Val)->getZExtValue();
+}

diff --git a/lib/IR/Module.cpp b/lib/IR/Module.cpp
index 3dd1f7e810b051ccfefae978e44743880ecef225..4f240c783e9053daeca4663c8558c1291de28284 100644 (file)
--- a/lib/IR/Module.cpp
+++ b/lib/IR/Module.cpp
@@ -318,11 +318,16 @@ getModuleFlagsMetadata(SmallVectorImpl<ModuleFlagEntry> &Flags) const {
 
   for (unsigned i = 0, e = ModFlags->getNumOperands(); i != e; ++i) {
     MDNode *Flag = ModFlags->getOperand(i);
-    ConstantInt *Behavior = cast<ConstantInt>(Flag->getOperand(0));
-    MDString *Key = cast<MDString>(Flag->getOperand(1));
-    Value *Val = Flag->getOperand(2);
-    Flags.push_back(ModuleFlagEntry(ModFlagBehavior(Behavior->getZExtValue()),
-                                    Key, Val));
+    if (Flag->getNumOperands() >= 3 && isa<ConstantInt>(Flag->getOperand(0)) &&
+        isa<MDString>(Flag->getOperand(1))) {
+      // Check the operands of the MDNode before accessing the operands.
+      // The verifier will actually catch these failures.
+      ConstantInt *Behavior = cast<ConstantInt>(Flag->getOperand(0));
+      MDString *Key = cast<MDString>(Flag->getOperand(1));
+      Value *Val = Flag->getOperand(2);
+      Flags.push_back(ModuleFlagEntry(ModFlagBehavior(Behavior->getZExtValue()),
+                                      Key, Val));
+    }
   }
 }
 

diff --git a/test/Bitcode/drop-debug-info.ll b/test/Bitcode/drop-debug-info.ll
new file mode 100644 (file)
index 0000000..da4ae0c
--- /dev/null
+++ b/test/Bitcode/drop-debug-info.ll
@@ -0,0 +1,26 @@
+; RUN: llvm-as < %s | llvm-dis | FileCheck %s
+
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval
+  ret i32 0, !dbg !12
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!9}
+
+!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.5 (trunk 195495) (llvm/trunk 195495:195504M)", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [/Users/manmanren/llvm_gmail/release/../llvm/tools/clang/test/CodeGen/debug-info-version.c] [DW_LANG_C99]
+!1 = metadata !{metadata !"../llvm/tools/clang/test/CodeGen/debug-info-version.c", metadata !"/Users/manmanren/llvm_gmail/release"}
+!2 = metadata !{i32 0}
+!3 = metadata !{metadata !4}
+!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"main", metadata !"main", metadata !"", i32 3, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, i32 ()* @main, null, null, metadata !2, i32 3} ; [ DW_TAG_subprogram ] [line 3] [def] [main]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [/Users/manmanren/llvm_gmail/release/../llvm/tools/clang/test/CodeGen/debug-info-version.c]
+!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !7, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
+!7 = metadata !{metadata !8}
+!8 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!9 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
+!12 = metadata !{i32 4, i32 0, metadata !4, null}
+
+; CHECK-NOT: !dbg
+; CHECK-NOT: !llvm.dbg.cu