[yaml2obj] - Add a Size field for StackSizesSection.

It is a follow-up requested in the review comment
for D67757. Allows to use Content + Size or just Size
when describing .stack_sizes sections in YAML document

Differential revision: https://reviews.llvm.org/D67958

llvm-svn: 372845

2 files changed, 30 insertions, 17 deletions

diff --git a/llvm/lib/ObjectYAML/ELFEmitter.cpp b/llvm/lib/ObjectYAML/ELFEmitter.cpp
index c394763459d..0139c2d1144 100644
--- a/llvm/lib/ObjectYAML/ELFEmitter.cpp
+++ b/llvm/lib/ObjectYAML/ELFEmitter.cpp
@@ -440,19 +440,20 @@ static size_t findFirstNonGlobal(ArrayRef<ELFYAML::Symbol> Symbols) {
   return Symbols.size();
 }
 
-static uint64_t writeRawSectionData(raw_ostream &OS,
-                                    const ELFYAML::RawContentSection &RawSec) {
+static uint64_t writeContent(raw_ostream &OS,
+                             const Optional<yaml::BinaryRef> &Content,
+                             const Optional<llvm::yaml::Hex64> &Size) {
   size_t ContentSize = 0;
-  if (RawSec.Content) {
-    RawSec.Content->writeAsBinary(OS);
-    ContentSize = RawSec.Content->binary_size();
+  if (Content) {
+    Content->writeAsBinary(OS);
+    ContentSize = Content->binary_size();
   }
 
-  if (!RawSec.Size)
+  if (!Size)
     return ContentSize;
 
-  OS.write_zeros(*RawSec.Size - ContentSize);
-  return *RawSec.Size;
+  OS.write_zeros(*Size - ContentSize);
+  return *Size;
 }
 
 template <class ELFT>
@@ -554,7 +555,7 @@ void ELFState<ELFT>::initSymtabSectionHeader(Elf_Shdr &SHeader,
   auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
   if (RawSec && (RawSec->Content || RawSec->Size)) {
     assert(Symbols.empty());
-    SHeader.sh_size = writeRawSectionData(OS, *RawSec);
+    SHeader.sh_size = writeContent(OS, RawSec->Content, RawSec->Size);
     return;
   }
 
@@ -579,7 +580,7 @@ void ELFState<ELFT>::initStrtabSectionHeader(Elf_Shdr &SHeader, StringRef Name,
 
   auto &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
   if (RawSec && (RawSec->Content || RawSec->Size)) {
-    SHeader.sh_size = writeRawSectionData(OS, *RawSec);
+    SHeader.sh_size = writeContent(OS, RawSec->Content, RawSec->Size);
   } else {
     STB.write(OS);
     SHeader.sh_size = STB.getSize();
@@ -675,7 +676,7 @@ void ELFState<ELFT>::writeSectionContent(
     ContiguousBlobAccumulator &CBA) {
   raw_ostream &OS =
       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
-  SHeader.sh_size = writeRawSectionData(OS, Section);
+  SHeader.sh_size = writeContent(OS, Section.Content, Section.Size);
 
   if (Section.EntSize)
     SHeader.sh_entsize = *Section.EntSize;
@@ -795,9 +796,8 @@ void ELFState<ELFT>::writeSectionContent(
   raw_ostream &OS =
       CBA.getOSAndAlignedOffset(SHeader.sh_offset, SHeader.sh_addralign);
 
-  if (Section.Content) {
-    Section.Content->writeAsBinary(OS);
-    SHeader.sh_size = Section.Content->binary_size();
+  if (Section.Content || Section.Size) {
+    SHeader.sh_size = writeContent(OS, Section.Content, Section.Size);
     return;
   }
 
diff --git a/llvm/lib/ObjectYAML/ELFYAML.cpp b/llvm/lib/ObjectYAML/ELFYAML.cpp
index af795f9732c..d369f14be4b 100644
--- a/llvm/lib/ObjectYAML/ELFYAML.cpp
+++ b/llvm/lib/ObjectYAML/ELFYAML.cpp
@@ -1020,6 +1020,7 @@ static void sectionMapping(IO &IO, ELFYAML::RawContentSection &Section) {
 static void sectionMapping(IO &IO, ELFYAML::StackSizesSection &Section) {
   commonSectionMapping(IO, Section);
   IO.mapOptional("Content", Section.Content);
+  IO.mapOptional("Size", Section.Size);
   IO.mapOptional("Entries", Section.Entries);
 }
 
@@ -1176,10 +1177,22 @@ StringRef MappingTraits<std::unique_ptr<ELFYAML::Section>>::validate(
   }
 
   if (const auto *SS = dyn_cast<ELFYAML::StackSizesSection>(Section.get())) {
-    if (SS->Content && SS->Entries)
+    if (!SS->Entries && !SS->Content && !SS->Size)
+      return ".stack_sizes: one of Content, Entries and Size must be specified";
+
+    if (SS->Size && SS->Content &&
+        (uint64_t)(*SS->Size) < SS->Content->binary_size())
+      return ".stack_sizes: Size must be greater than or equal to the content "
+             "size";
+
+    // We accept Content, Size or both together when there are no Entries.
+    if (!SS->Entries)
+      return {};
+
+    if (SS->Size)
+      return ".stack_sizes: Size and Entries cannot be used together";
+    if (SS->Content)
       return ".stack_sizes: Content and Entries cannot be used together";
-    if (!SS->Content && !SS->Entries)
-      return ".stack_sizes: either Content or Entries tag must be specified";
     return {};
   }
   return {};