PR21189: Teach llvm-readobj to dump bits of COFF symbol subsections required to debug using VS2012+

Reviewed at http://reviews.llvm.org/D5755
Thanks to Andrey Guskov for his help investigating this!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220526 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 82 insertions, 0 deletions

diff --git a/tools/llvm-readobj/COFFDumper.cpp b/tools/llvm-readobj/COFFDumper.cpp
index dc280a634dc..6242a790f5a 100644
--- a/tools/llvm-readobj/COFFDumper.cpp
+++ b/tools/llvm-readobj/COFFDumper.cpp
@@ -69,6 +69,10 @@ private:
 
   void printCodeViewLineTables(const SectionRef &Section);
 
+  void printCodeViewSymbolsSubsection(StringRef Subsection,
+                                      const SectionRef &Section,
+                                      uint32_t Offset);
+
   void cacheRelocations();
 
   std::error_code resolveSymbol(const coff_section *Section, uint64_t Offset,
@@ -444,6 +448,7 @@ void COFFDumper::printCodeViewLineTables(const SectionRef &Section) {
 
   ListScope D(W, "CodeViewLineTables");
   {
+    // FIXME: Add more offset correctness checks.
     DataExtractor DE(Data, true, 4);
     uint32_t Offset = 0,
              Magic = DE.getU32(&Offset);
@@ -473,6 +478,9 @@ void COFFDumper::printCodeViewLineTables(const SectionRef &Section) {
       W.printBinaryBlock("Contents", Contents);
 
       switch (SubSectionType) {
+      case COFF::DEBUG_SYMBOL_SUBSECTION:
+        printCodeViewSymbolsSubsection(Contents, Section, Offset);
+        break;
       case COFF::DEBUG_LINE_TABLE_SUBSECTION: {
         // Holds a PC to file:line table.  Some data to parse this subsection is
         // stored in the other subsections, so just check sanity and store the
@@ -592,6 +600,80 @@ void COFFDumper::printCodeViewLineTables(const SectionRef &Section) {
   }
 }
 
+void COFFDumper::printCodeViewSymbolsSubsection(StringRef Subsection,
+                                                const SectionRef &Section,
+                                                uint32_t OffsetInSection) {
+  if (Subsection.size() == 0) {
+    error(object_error::parse_failed);
+    return;
+  }
+  DataExtractor DE(Subsection, true, 4);
+  uint32_t Offset = 0;
+
+  // Function-level subsections have "procedure start" and "procedure end"
+  // commands that should come in pairs and surround relevant info.
+  bool InFunctionScope = false;
+  while (DE.isValidOffset(Offset)) {
+    // Read subsection segments one by one.
+    uint16_t Size = DE.getU16(&Offset);
+    // The section size includes the size of the type identifier.
+    if (Size < 2 || !DE.isValidOffsetForDataOfSize(Offset, Size)) {
+      error(object_error::parse_failed);
+      return;
+    }
+    Size -= 2;
+    uint16_t Type = DE.getU16(&Offset);
+    switch (Type) {
+    case COFF::DEBUG_SYMBOL_TYPE_PROC_START: {
+      DictScope S(W, "ProcStart");
+      if (InFunctionScope || Size < 36) {
+        error(object_error::parse_failed);
+        return;
+      }
+      InFunctionScope = true;
+
+      // We're currently interested in a limited subset of fields in this
+      // segment, just ignore the rest of the fields for now.
+      uint8_t Unused[12];
+      DE.getU8(&Offset, Unused, 12);
+      uint32_t CodeSize = DE.getU32(&Offset);
+      DE.getU8(&Offset, Unused, 12);
+      StringRef SectionName;
+      if (error(resolveSymbolName(Obj->getCOFFSection(Section),
+                                  OffsetInSection + Offset, SectionName)))
+        return;
+      Offset += 4;
+      DE.getU8(&Offset, Unused, 3);
+      StringRef FunctionName = DE.getCStr(&Offset);
+      if (!DE.isValidOffset(Offset)) {
+        error(object_error::parse_failed);
+        return;
+      }
+      W.printString("FunctionName", FunctionName);
+      W.printString("Section", SectionName);
+      W.printHex("CodeSize", CodeSize);
+
+      break;
+    }
+    case COFF::DEBUG_SYMBOL_TYPE_PROC_END: {
+      W.startLine() << "ProcEnd\n";
+      if (!InFunctionScope || Size > 0) {
+        error(object_error::parse_failed);
+        return;
+      }
+      InFunctionScope = false;
+      break;
+    }
+    default:
+      Offset += Size;
+      break;
+    }
+  }
+
+  if (InFunctionScope)
+    error(object_error::parse_failed);
+}
+
 void COFFDumper::printSections() {
   ListScope SectionsD(W, "Sections");
   int SectionNumber = 0;