[llvm] 3d4c873 - [yaml2obj] - Map section names to chunks for each ELFYAML::ProgramHeader early. NFCI.

[Georgii Rymar via llvm-commits]

Author: Georgii Rymar
Date: 2020-05-26T12:32:10+03:00
New Revision: 3d4c873a14fe2ffb5cd6ac329354857eef245196

URL: https://github.com/llvm/llvm-project/commit/3d4c873a14fe2ffb5cd6ac329354857eef245196
DIFF: https://github.com/llvm/llvm-project/commit/3d4c873a14fe2ffb5cd6ac329354857eef245196.diff

LOG: [yaml2obj] - Map section names to chunks for each ELFYAML::ProgramHeader early. NFCI.

Each `ELFYAML::ProgramHeader` currently contains a list of section names
included. We are trying to map them to Fill/Sections very late,
though we can create such mapping early, in `initProgramHeaders`.

The benefit is that with such change it is possible to access mapped
chunks earlier (for example during writing section content) and have
simpler code.

Differential revision: https://reviews.llvm.org/D80520

Added: 
    

Modified: 
    llvm/include/llvm/ObjectYAML/ELFYAML.h
    llvm/lib/ObjectYAML/ELFEmitter.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/ObjectYAML/ELFYAML.h b/llvm/include/llvm/ObjectYAML/ELFYAML.h
index 2fd18fcd2957..22ed82289ca8 100644
--- a/llvm/include/llvm/ObjectYAML/ELFYAML.h
+++ b/llvm/include/llvm/ObjectYAML/ELFYAML.h
@@ -90,18 +90,6 @@ struct SectionName {
   StringRef Section;
 };
 
-struct ProgramHeader {
-  ELF_PT Type;
-  ELF_PF Flags;
-  llvm::yaml::Hex64 VAddr;
-  llvm::yaml::Hex64 PAddr;
-  Optional<llvm::yaml::Hex64> Align;
-  Optional<llvm::yaml::Hex64> FileSize;
-  Optional<llvm::yaml::Hex64> MemSize;
-  Optional<llvm::yaml::Hex64> Offset;
-  std::vector<SectionName> Sections;
-};
-
 struct Symbol {
   StringRef Name;
   ELF_STT Type;
@@ -503,6 +491,21 @@ struct MipsABIFlags : Section {
   }
 };
 
+struct ProgramHeader {
+  ELF_PT Type;
+  ELF_PF Flags;
+  llvm::yaml::Hex64 VAddr;
+  llvm::yaml::Hex64 PAddr;
+  Optional<llvm::yaml::Hex64> Align;
+  Optional<llvm::yaml::Hex64> FileSize;
+  Optional<llvm::yaml::Hex64> MemSize;
+  Optional<llvm::yaml::Hex64> Offset;
+
+  std::vector<SectionName> Sections;
+  // This vector is parallel to Sections and contains corresponding chunks.
+  std::vector<Chunk *> Chunks;
+};
+
 struct Object {
   FileHeader Header;
   std::vector<ProgramHeader> ProgramHeaders;

diff  --git a/llvm/lib/ObjectYAML/ELFEmitter.cpp b/llvm/lib/ObjectYAML/ELFEmitter.cpp
index 95d74eeeb6e6..78093491704b 100644
--- a/llvm/lib/ObjectYAML/ELFEmitter.cpp
+++ b/llvm/lib/ObjectYAML/ELFEmitter.cpp
@@ -330,7 +330,13 @@ void ELFState<ELFT>::writeELFHeader(ContiguousBlobAccumulator &CBA, raw_ostream
 
 template <class ELFT>
 void ELFState<ELFT>::initProgramHeaders(std::vector<Elf_Phdr> &PHeaders) {
-  for (const auto &YamlPhdr : Doc.ProgramHeaders) {
+  DenseMap<StringRef, ELFYAML::Fill *> NameToFill;
+  for (const std::unique_ptr<ELFYAML::Chunk> &D : Doc.Chunks)
+    if (auto S = dyn_cast<ELFYAML::Fill>(D.get()))
+      NameToFill[S->Name] = S;
+
+  std::vector<ELFYAML::Section *> Sections = Doc.getSections();
+  for (ELFYAML::ProgramHeader &YamlPhdr : Doc.ProgramHeaders) {
     Elf_Phdr Phdr;
     zero(Phdr);
     Phdr.p_type = YamlPhdr.Type;
@@ -338,6 +344,23 @@ void ELFState<ELFT>::initProgramHeaders(std::vector<Elf_Phdr> &PHeaders) {
     Phdr.p_vaddr = YamlPhdr.VAddr;
     Phdr.p_paddr = YamlPhdr.PAddr;
     PHeaders.push_back(Phdr);
+
+    // Map Sections list to corresponding chunks.
+    for (const ELFYAML::SectionName &SecName : YamlPhdr.Sections) {
+      if (ELFYAML::Fill *Fill = NameToFill.lookup(SecName.Section)) {
+        YamlPhdr.Chunks.push_back(Fill);
+        continue;
+      }
+
+      unsigned Index;
+      if (SN2I.lookup(SecName.Section, Index)) {
+        YamlPhdr.Chunks.push_back(Sections[Index]);
+        continue;
+      }
+
+      reportError("unknown section or fill referenced: '" + SecName.Section +
+                  "' by program header");
+    }
   }
 }
 
@@ -757,31 +780,19 @@ template <class ELFT> void ELFState<ELFT>::reportError(const Twine &Msg) {
 template <class ELFT>
 std::vector<Fragment>
 ELFState<ELFT>::getPhdrFragments(const ELFYAML::ProgramHeader &Phdr,
-                                 ArrayRef<typename ELFT::Shdr> SHeaders) {
-  DenseMap<StringRef, ELFYAML::Fill *> NameToFill;
-  for (const std::unique_ptr<ELFYAML::Chunk> &D : Doc.Chunks)
-    if (auto S = dyn_cast<ELFYAML::Fill>(D.get()))
-      NameToFill[S->Name] = S;
-
+                                 ArrayRef<Elf_Shdr> SHeaders) {
   std::vector<Fragment> Ret;
-  for (const ELFYAML::SectionName &SecName : Phdr.Sections) {
-    unsigned Index;
-    if (SN2I.lookup(SecName.Section, Index)) {
-      const typename ELFT::Shdr &H = SHeaders[Index];
-      Ret.push_back({H.sh_offset, H.sh_size, H.sh_type, H.sh_addralign});
-      continue;
-    }
-
-    if (ELFYAML::Fill *Fill = NameToFill.lookup(SecName.Section)) {
-      Ret.push_back({*Fill->Offset, Fill->Size, llvm::ELF::SHT_PROGBITS,
+  for (const ELFYAML::Chunk *C : Phdr.Chunks) {
+    if (const ELFYAML::Fill *F = dyn_cast<ELFYAML::Fill>(C)) {
+      Ret.push_back({*F->Offset, F->Size, llvm::ELF::SHT_PROGBITS,
                      /*ShAddrAlign=*/1});
       continue;
     }
 
-    reportError("unknown section or fill referenced: '" + SecName.Section +
-                "' by program header");
+    const ELFYAML::Section *S = cast<ELFYAML::Section>(C);
+    const Elf_Shdr &H = SHeaders[SN2I.get(S->Name)];
+    Ret.push_back({H.sh_offset, H.sh_size, H.sh_type, H.sh_addralign});
   }
-
   return Ret;
 }