Modify DWARFFormValue to remember the DWARFUnit that it was decoded with.

Modifying DWARFFormValue to remember the DWARFUnit that it was encoded with can simplify the usage of instances of this class. Previously users would have to try and pass in the same DWARFUnit that was used to decode the form value and there was a possibility that a different DWARFUnit might be supplied to the functions that extract values (strings, CU relative references, addresses) and cause problems. This fixes this potential issue by storing the DWARFUnit inside the DWARFFormValue so that this mistake can't be made. Instances of DWARFFormValue are not stored permanently and are used as temporary values, so the increase in size of an instance of DWARFFormValue isn't a big deal. This makes decoding form values more bullet proof and is a change that will be used by future modifications.

https://reviews.llvm.org/D26052

llvm-svn: 285594

1 files changed, 29 insertions, 25 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp b/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp
index a2d625a06de..5d9c118473a 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp
@@ -133,8 +133,10 @@ bool DWARFFormValue::isFormClass(DWARFFormValue::FormClass FC) const {
          FC == FC_SectionOffset;
 }
 
-bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
+bool DWARFFormValue::extractValue(const DataExtractor &data, 
+                                  uint32_t *offset_ptr,
                                   const DWARFUnit *cu) {
+  U = cu;
   bool indirect = false;
   bool is_block = false;
   Value.data = nullptr;
@@ -145,14 +147,14 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
     switch (Form) {
     case DW_FORM_addr:
     case DW_FORM_ref_addr: {
-      if (!cu)
+      if (!U)
         return false;
       uint16_t AddrSize =
           (Form == DW_FORM_addr)
-              ? cu->getAddressByteSize()
-              : getRefAddrSize(cu->getAddressByteSize(), cu->getVersion());
-      RelocAddrMap::const_iterator AI = cu->getRelocMap()->find(*offset_ptr);
-      if (AI != cu->getRelocMap()->end()) {
+              ? U->getAddressByteSize()
+              : U->getRefAddrByteSize();
+      RelocAddrMap::const_iterator AI = U->getRelocMap()->find(*offset_ptr);
+      if (AI != U->getRelocMap()->end()) {
         const std::pair<uint8_t, int64_t> &R = AI->second;
         Value.uval = data.getUnsigned(offset_ptr, AddrSize) + R.second;
       } else
@@ -188,10 +190,10 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
     case DW_FORM_data4:
     case DW_FORM_ref4: {
       Value.uval = data.getU32(offset_ptr);
-      if (!cu)
+      if (!U)
         break;
-      RelocAddrMap::const_iterator AI = cu->getRelocMap()->find(*offset_ptr-4);
-      if (AI != cu->getRelocMap()->end())
+      RelocAddrMap::const_iterator AI = U->getRelocMap()->find(*offset_ptr-4);
+      if (AI != U->getRelocMap()->end())
         Value.uval += AI->second.second;
       break;
     }
@@ -219,11 +221,11 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
     case DW_FORM_GNU_strp_alt: {
       // FIXME: This is 64-bit for DWARF64.
       Value.uval = data.getU32(offset_ptr);
-      if (!cu)
+      if (!U)
         break;
       RelocAddrMap::const_iterator AI =
-          cu->getRelocMap()->find(*offset_ptr - 4);
-      if (AI != cu->getRelocMap()->end())
+          U->getRelocMap()->find(*offset_ptr - 4);
+      if (AI != U->getRelocMap()->end())
         Value.uval += AI->second.second;
       break;
     }
@@ -256,8 +258,8 @@ bool DWARFFormValue::extractValue(DataExtractor data, uint32_t *offset_ptr,
 
 bool
 DWARFFormValue::skipValue(DataExtractor debug_info_data, uint32_t* offset_ptr,
-                          const DWARFUnit *cu) const {
-  return DWARFFormValue::skipValue(Form, debug_info_data, offset_ptr, cu);
+                          const DWARFUnit *U) const {
+  return DWARFFormValue::skipValue(Form, debug_info_data, offset_ptr, U);
 }
 
 bool
@@ -371,7 +373,7 @@ DWARFFormValue::skipValue(dwarf::Form form, DataExtractor debug_info_data,
 }
 
 void
-DWARFFormValue::dump(raw_ostream &OS, const DWARFUnit *cu) const {
+DWARFFormValue::dump(raw_ostream &OS) const {
   uint64_t uvalue = Value.uval;
   bool cu_relative_offset = false;
 
@@ -380,7 +382,9 @@ DWARFFormValue::dump(raw_ostream &OS, const DWARFUnit *cu) const {
   case DW_FORM_GNU_addr_index: {
     OS << format(" indexed (%8.8x) address = ", (uint32_t)uvalue);
     uint64_t Address;
-    if (cu->getAddrOffsetSectionItem(uvalue, Address))
+    if (U == nullptr)
+      OS << "<invalid dwarf unit>";
+    else if (U->getAddrOffsetSectionItem(uvalue, Address))
       OS << format("0x%016" PRIx64, Address);
     else
       OS << "<no .debug_addr section>";
@@ -431,17 +435,17 @@ DWARFFormValue::dump(raw_ostream &OS, const DWARFUnit *cu) const {
   case DW_FORM_udata:     OS << Value.uval; break;
   case DW_FORM_strp: {
     OS << format(" .debug_str[0x%8.8x] = ", (uint32_t)uvalue);
-    dumpString(OS, cu);
+    dumpString(OS);
     break;
   }
   case DW_FORM_GNU_str_index: {
     OS << format(" indexed (%8.8x) string = ", (uint32_t)uvalue);
-    dumpString(OS, cu);
+    dumpString(OS);
     break;
   }
   case DW_FORM_GNU_strp_alt: {
     OS << format("alt indirect string, offset: 0x%" PRIx64 "", uvalue);
-    dumpString(OS, cu);
+    dumpString(OS);
     break;
   }
   case DW_FORM_ref_addr:
@@ -490,13 +494,13 @@ DWARFFormValue::dump(raw_ostream &OS, const DWARFUnit *cu) const {
   if (cu_relative_offset) {
     OS << " => {";
     WithColor(OS, syntax::Address).get()
-      << format("0x%8.8" PRIx64, uvalue + (cu ? cu->getOffset() : 0));
+      << format("0x%8.8" PRIx64, uvalue + (U ? U->getOffset() : 0));
     OS << "}";
   }
 }
 
-void DWARFFormValue::dumpString(raw_ostream &OS, const DWARFUnit *U) const {
-  Optional<const char *> DbgStr = getAsCString(U);
+void DWARFFormValue::dumpString(raw_ostream &OS) const {
+  Optional<const char *> DbgStr = getAsCString();
   if (DbgStr.hasValue()) {
     raw_ostream &COS = WithColor(OS, syntax::String);
     COS << '"';
@@ -505,7 +509,7 @@ void DWARFFormValue::dumpString(raw_ostream &OS, const DWARFUnit *U) const {
   }
 }
 
-Optional<const char *> DWARFFormValue::getAsCString(const DWARFUnit *U) const {
+Optional<const char *> DWARFFormValue::getAsCString() const {
   if (!isFormClass(FC_String))
     return None;
   if (Form == DW_FORM_string)
@@ -526,7 +530,7 @@ Optional<const char *> DWARFFormValue::getAsCString(const DWARFUnit *U) const {
   return None;
 }
 
-Optional<uint64_t> DWARFFormValue::getAsAddress(const DWARFUnit *U) const {
+Optional<uint64_t> DWARFFormValue::getAsAddress() const {
   if (!isFormClass(FC_Address))
     return None;
   if (Form == DW_FORM_GNU_addr_index) {
@@ -539,7 +543,7 @@ Optional<uint64_t> DWARFFormValue::getAsAddress(const DWARFUnit *U) const {
   return Value.uval;
 }
 
-Optional<uint64_t> DWARFFormValue::getAsReference(const DWARFUnit *U) const {
+Optional<uint64_t> DWARFFormValue::getAsReference() const {
   if (!isFormClass(FC_Reference))
     return None;
   switch (Form) {