From: Zachary Turner <zturner@google.com>
Date: Tue, 20 Jun 2017 18:50:55 +0000 (+0000)
Subject: [PDB] Don't write uninitialized bytes to a PDB file.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6ebce80ed17745cab6920e6b6c9050129255efcf;p=llvm

[PDB] Don't write uninitialized bytes to a PDB file.

There were certain fields that we didn't know how to write, as
well as various padding bytes that we would ignore.  This leads
to garbage data in the PDB.  While not strictly necessary, we
should initialize these bytes to something meaningful, as it
makes for easier binary comparison between PDBs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305819 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp b/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
index 59ecbb50143..745dd742aad 100644
--- a/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
+++ b/lib/DebugInfo/PDB/Native/DbiModuleDescriptorBuilder.cpp
@@ -51,6 +51,7 @@ DbiModuleDescriptorBuilder::DbiModuleDescriptorBuilder(StringRef ModuleName,
                                                        uint32_t ModIndex,
                                                        msf::MSFBuilder &Msf)
     : MSF(Msf), ModuleName(ModuleName) {
+  ::memset(&Layout, 0, sizeof(Layout));
   Layout.Mod = ModIndex;
 }
 
@@ -102,6 +103,7 @@ template <typename T> struct Foo {
 template <typename T> Foo<T> makeFoo(T &&t) { return Foo<T>(std::move(t)); }
 
 void DbiModuleDescriptorBuilder::finalize() {
+  Layout.SC.ModuleIndex = Layout.Mod;
   Layout.FileNameOffs = 0; // TODO: Fix this
   Layout.Flags = 0;        // TODO: Fix this
   Layout.C11Bytes = 0;
diff --git a/lib/DebugInfo/PDB/Native/DbiStreamBuilder.cpp b/lib/DebugInfo/PDB/Native/DbiStreamBuilder.cpp
index 0ad461546d7..aad247ea185 100644
--- a/lib/DebugInfo/PDB/Native/DbiStreamBuilder.cpp
+++ b/lib/DebugInfo/PDB/Native/DbiStreamBuilder.cpp
@@ -237,6 +237,7 @@ Error DbiStreamBuilder::finalize() {
     return EC;
 
   DbiStreamHeader *H = Allocator.Allocate<DbiStreamHeader>();
+  ::memset(H, 0, sizeof(DbiStreamHeader));
   H->VersionHeader = *VerHeader;
   H->VersionSignature = -1;
   H->Age = Age;