[llvm] db5b7b3 - [XCOFF] Fix the offset error of dwarf sections caused by D137819.

[via llvm-commits]

Author: esmeyi
Date: 2023-01-10T12:32:13-05:00
New Revision: db5b7b3fe28dfdd4a038c7aac3fce1678765b9e6

URL: https://github.com/llvm/llvm-project/commit/db5b7b3fe28dfdd4a038c7aac3fce1678765b9e6
DIFF: https://github.com/llvm/llvm-project/commit/db5b7b3fe28dfdd4a038c7aac3fce1678765b9e6.diff

LOG: [XCOFF] Fix the offset error of dwarf sections caused by D137819.

Added: 
    

Modified: 
    llvm/lib/MC/XCOFFObjectWriter.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/MC/XCOFFObjectWriter.cpp b/llvm/lib/MC/XCOFFObjectWriter.cpp
index 980b014e832f3..0657ed2156593 100644
--- a/llvm/lib/MC/XCOFFObjectWriter.cpp
+++ b/llvm/lib/MC/XCOFFObjectWriter.cpp
@@ -238,6 +238,7 @@ class XCOFFObjectWriter : public MCObjectWriter {
   uint32_t SymbolTableEntryCount = 0;
   uint64_t SymbolTableOffset = 0;
   uint16_t SectionCount = 0;
+  uint32_t PaddingsBeforeDwarf = 0;
   std::vector<std::pair<std::string, size_t>> FileNames;
   bool HasVisibility = false;
 
@@ -416,6 +417,7 @@ void XCOFFObjectWriter::reset() {
   SymbolTableEntryCount = 0;
   SymbolTableOffset = 0;
   SectionCount = 0;
+  PaddingsBeforeDwarf = 0;
   Strings.clear();
 
   MCObjectWriter::reset();
@@ -1148,7 +1150,6 @@ void XCOFFObjectWriter::finalizeSectionInfo() {
       auxiliaryHeaderSize();
 
   // Calculate the file offset to the section data.
-  uint64_t CurrAddress = 0;
   for (auto *Sec : Sections) {
     if (Sec->Index == SectionEntry::UninitializedIndex || Sec->IsVirtual)
       continue;
@@ -1157,19 +1158,10 @@ void XCOFFObjectWriter::finalizeSectionInfo() {
     RawPointer += Sec->Size;
     if (RawPointer > MaxRawDataSize)
       report_fatal_error("Section raw data overflowed this object file.");
-
-    CurrAddress = Sec->Address + Sec->Size;
   }
 
-  // Sections other than DWARF section use DefaultSectionAlign as the default
-  // alignment, while DWARF sections have their own alignments. If these two
-  // alignments are not the same, we need some padding here and to use this
-  // padding in FileOffsetToData calculation.
   if (!DwarfSections.empty()) {
-    RawPointer +=
-        alignTo(CurrAddress,
-                (*DwarfSections.begin()).DwarfSect->MCSec->getAlign()) -
-        CurrAddress;
+    RawPointer += PaddingsBeforeDwarf;
     for (auto &DwarfSection : DwarfSections) {
       DwarfSection.FileOffsetToData = RawPointer;
       RawPointer += DwarfSection.MemorySize;
@@ -1345,7 +1337,17 @@ void XCOFFObjectWriter::assignAddressesAndIndices(const MCAsmLayout &Layout) {
     Section->Size = Address - Section->Address;
   }
 
-  // Start to generate DWARF sections.
+  // Start to generate DWARF sections. Sections other than DWARF section use
+  // DefaultSectionAlign as the default alignment, while DWARF sections have
+  // their own alignments. If these two alignments are not the same, we need
+  // some paddings here and record the paddings bytes for FileOffsetToData
+  // calculation.
+  if (!DwarfSections.empty())
+    PaddingsBeforeDwarf =
+        alignTo(Address,
+                (*DwarfSections.begin()).DwarfSect->MCSec->getAlign()) -
+        Address;
+
   DwarfSectionEntry *LastDwarfSection = nullptr;
   for (auto &DwarfSection : DwarfSections) {
     assert((SectionIndex <= MaxSectionIndex) && "Section index overflow!");