From 27457ac42f7a9267ab7e0190424a95fecf0ea201 Mon Sep 17 00:00:00 2001
From: Manman Ren <manman.ren@gmail.com>
Date: Mon, 9 Dec 2013 21:06:30 +0000
Subject: Merging r196158:
 ------------------------------------------------------------------------
 r196158 | mren | 2013-12-02 13:29:56 -0800 (Mon, 02 Dec 2013) | 12 lines

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/branches/release_34@196822 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/AsmParser/LLParser.cpp           |  2 ++
 lib/Bitcode/Reader/BitcodeReader.cpp |  1 +
 lib/IR/AutoUpgrade.cpp               | 10 ++++++++++
 lib/IR/DebugInfo.cpp                 |  8 ++++++++
 lib/IR/Module.cpp                    | 15 ++++++++++-----
 5 files changed, 31 insertions(+), 5 deletions(-)

(limited to 'lib')

diff --git a/lib/AsmParser/LLParser.cpp b/lib/AsmParser/LLParser.cpp
index 20fa0f4eab..3b903cdb09 100644
--- 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 2c95c920f8..ce3b7d163e 100644
--- 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 6f79919f24..32cfe278c7 100644
--- 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 5dcc6f6590..9abc8e9947 100644
--- a/lib/IR/DebugInfo.cpp
+++ b/lib/IR/DebugInfo.cpp
@@ -1478,3 +1478,11 @@ 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 3dd1f7e810..4f240c783e 100644
--- 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));
+    }
   }
 }
 
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