This patch improves the MCJIT runtime dynamic loader by adding new handling

of zero-initialized sections, virtual sections and common symbols
and preventing the loading of sections which are not required for
execution such as debug information.

Patch by Andy Kaylor!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154610 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 0 deletions

diff --git a/include/llvm/Object/ObjectFile.h b/include/llvm/Object/ObjectFile.h
index d8cda81533..4dd7fb5813 100644
--- a/include/llvm/Object/ObjectFile.h
+++ b/include/llvm/Object/ObjectFile.h
@@ -158,11 +158,16 @@ public:
   error_code isText(bool &Result) const;
   error_code isData(bool &Result) const;
   error_code isBSS(bool &Result) const;
+  error_code isRequiredForExecution(bool &Result) const;
+  error_code isVirtual(bool &Result) const;
+  error_code isZeroInit(bool &Result) const;
 
   error_code containsSymbol(SymbolRef S, bool &Result) const;
 
   relocation_iterator begin_relocations() const;
   relocation_iterator end_relocations() const;
+
+  DataRefImpl getRawDataRefImpl() const;
 };
 typedef content_iterator<SectionRef> section_iterator;
 
@@ -217,6 +222,9 @@ public:
   /// Get symbol flags (bitwise OR of SymbolRef::Flags)
   error_code getFlags(uint32_t &Result) const;
 
+  /// @brief Return true for common symbols such as uninitialized globals
+  error_code isCommon(bool &Result) const;
+
   /// @brief Get section this symbol is defined in reference to. Result is
   /// end_sections() if it is undefined or is an absolute symbol.
   error_code getSection(section_iterator &Result) const;
@@ -299,6 +307,11 @@ protected:
   virtual error_code isSectionText(DataRefImpl Sec, bool &Res) const = 0;
   virtual error_code isSectionData(DataRefImpl Sec, bool &Res) const = 0;
   virtual error_code isSectionBSS(DataRefImpl Sec, bool &Res) const = 0;
+  virtual error_code isSectionRequiredForExecution(DataRefImpl Sec,
+                                                   bool &Res) const = 0;
+  // A section is 'virtual' if its contents aren't present in the object image.
+  virtual error_code isSectionVirtual(DataRefImpl Sec, bool &Res) const = 0;
+  virtual error_code isSectionZeroInit(DataRefImpl Sec, bool &Res) const = 0;
   virtual error_code sectionContainsSymbol(DataRefImpl Sec, DataRefImpl Symb,
                                            bool &Result) const = 0;
   virtual relocation_iterator getSectionRelBegin(DataRefImpl Sec) const = 0;
@@ -481,6 +494,18 @@ inline error_code SectionRef::isBSS(bool &Result) const {
   return OwningObject->isSectionBSS(SectionPimpl, Result);
 }
 
+inline error_code SectionRef::isRequiredForExecution(bool &Result) const {
+  return OwningObject->isSectionRequiredForExecution(SectionPimpl, Result);
+}
+
+inline error_code SectionRef::isVirtual(bool &Result) const {
+  return OwningObject->isSectionVirtual(SectionPimpl, Result);
+}
+
+inline error_code SectionRef::isZeroInit(bool &Result) const {
+  return OwningObject->isSectionZeroInit(SectionPimpl, Result);
+}
+
 inline error_code SectionRef::containsSymbol(SymbolRef S, bool &Result) const {
   return OwningObject->sectionContainsSymbol(SectionPimpl, S.SymbolPimpl,
                                              Result);
@@ -494,6 +519,9 @@ inline relocation_iterator SectionRef::end_relocations() const {
   return OwningObject->getSectionRelEnd(SectionPimpl);
 }
 
+inline DataRefImpl SectionRef::getRawDataRefImpl() const {
+  return SectionPimpl;
+}
 
 /// RelocationRef
 inline RelocationRef::RelocationRef(DataRefImpl RelocationP,