Resubmit "Fix bug in PE/COFF plugin."

The original commit was actually 2 unrelated bug fixes, but it turns
out the second bug fix wasn't quite correct, so the entire patch was
reverted.  Resubmitting this half of the patch by itself, then will
follow up with a new patch which fixes the rest of the issue in a
more appropriate way.

llvm-svn: 346505

lldb/lit/SymbolFile/NativePDB/Inputs/globals-bss.lldbinit

@@ -0,0 +1,3 @@
+target variable GlobalVariable
+
+quit

lldb/lit/SymbolFile/NativePDB/ast-reconstruction.cpp

@@ -90,15 +90,15 @@ Anonymous<A::B::C<int>>::D AnonABCVoidD;
 // CHECK: (TrivialS) TS = {}
 // CHECK: (TrivialU) TU = {}
 // CHECK: (TrivialE) TE = <Unable to determine byte size.>
-// CHECK: (A::B::C<int>) ABCInt = (ABCMember = <read memory from {{.*}} failed>)
+// CHECK: (A::B::C<int>) ABCInt = (ABCMember = 0)
-// CHECK: (A::B::C<float>) ABCFloat = (ABCMember = <read memory from {{.*}} failed>)
+// CHECK: (A::B::C<float>) ABCFloat = (ABCMember = 0)
-// CHECK: (A::B::C<void>) ABCVoid = (ABCSpecializationMember = <read memory from {{.*}} failed>)
+// CHECK: (A::B::C<void>) ABCVoid = (ABCSpecializationMember = 0x0000000000000000)
 // CHECK: (A::C<0>) AC0 = {}
 // CHECK: (A::C<-1>) ACNeg1 = {}
-// CHECK: (A::C<0>::D) AC0D = (ACDMember = <read memory from {{.*}} failed>, CPtr = <read memory from {{.*}} failed>)
+// CHECK: (A::C<0>::D) AC0D = (ACDMember = 0, CPtr = 0x0000000000000000)
-// CHECK: (A::C<-1>::D) ACNeg1D = (ACDMember = <read memory from {{.*}} failed>, CPtr = <read memory from {{.*}} failed>)
+// CHECK: (A::C<-1>::D) ACNeg1D = (ACDMember = 0, CPtr = 0x0000000000000000)
 // CHECK: (A::D) AD = {}
-// CHECK: (A::D::E) ADE = (ADDMember = <read memory from {{.*}} failed>)
+// CHECK: (A::D::E) ADE = (ADDMember = 0)
 // CHECK: Dumping clang ast for 1 modules.
 // CHECK: TranslationUnitDecl {{.*}}
 // CHECK: |-CXXRecordDecl {{.*}} class TrivialC definition

lldb/lit/SymbolFile/NativePDB/globals-bss.cpp

@@ -0,0 +1,35 @@
+// clang-format off
+// REQUIRES: lld
+
+// Make sure we can read variables from BSS
+// RUN: clang-cl /Z7 /GS- /GR- /c /Fo%t.obj -- %s
+// RUN: lld-link /DEBUG /nodefaultlib /entry:main /OUT:%t.exe /PDB:%t.pdb -- %t.obj
+// RUN: llvm-readobj -s %t.exe | FileCheck --check-prefix=BSS %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=1 lldb -f %t.exe -s \
+// RUN:     %p/Inputs/globals-bss.lldbinit 2>&1 | FileCheck %s
+
+int GlobalVariable = 0;
+
+int main(int argc, char **argv) {
+  return 0;
+}
+
+// BSS:       Section {
+// BSS:         Number: 3
+// BSS:         Name: .data
+// BSS-NEXT:    VirtualSize: 0x4
+// BSS-NEXT:    VirtualAddress:
+// BSS-NEXT:    RawDataSize: 0
+// BSS-NEXT:    PointerToRawData: 0x0
+// BSS-NEXT:    PointerToRelocations: 0x0
+// BSS-NEXT:    PointerToLineNumbers: 0x0
+// BSS-NEXT:    RelocationCount: 0
+// BSS-NEXT:    LineNumberCount: 0
+// BSS-NEXT:    Characteristics [ (0xC0000040)
+// BSS-NEXT:      IMAGE_SCN_CNT_INITIALIZED_DATA (0x40)
+// BSS-NEXT:      IMAGE_SCN_MEM_READ (0x40000000)
+// BSS-NEXT:      IMAGE_SCN_MEM_WRITE (0x80000000)
+// BSS-NEXT:    ]
+// BSS-NEXT:  }
+
+// CHECK: (int) GlobalVariable = 0

lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

@@ -710,7 +710,10 @@ void ObjectFilePECOFF::CreateSections(SectionList &unified_section_list) {
                        llvm::COFF::IMAGE_SCN_CNT_INITIALIZED_DATA &&
                    ((const_sect_name == g_data_sect_name) ||
                     (const_sect_name == g_DATA_sect_name))) {
-          section_type = eSectionTypeData;
+          if (m_sect_headers[idx].size == 0 && m_sect_headers[idx].offset == 0)
+            section_type = eSectionTypeZeroFill;
+          else
+            section_type = eSectionTypeData;
         } else if (m_sect_headers[idx].flags &
                        llvm::COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA &&
                    ((const_sect_name == g_bss_sect_name) ||
@@ -1053,6 +1056,7 @@ ObjectFile::Type ObjectFilePECOFF::CalculateType() {
 }
 
 ObjectFile::Strata ObjectFilePECOFF::CalculateStrata() { return eStrataUser; }
+
 //------------------------------------------------------------------
 // PluginInterface protocol
 //------------------------------------------------------------------