Fix program header propagation.

Propagate program headers by walking the commands, not the
sections. This allows us to propagate program headers even from
sections that don't end up in the output.

Fixes pr30997.

llvm-svn: 286837

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 2cf088e..c8ca74a 100644 (file)
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -563,6 +563,35 @@ template <class ELFT> void LinkerScript<ELFT>::adjustSectionsBeforeSorting() {
     auto *OutSec = make<OutputSection<ELFT>>(Cmd->Name, Type, Flags);
     OutputSections->push_back(OutSec);
   }
+}
+
+template <class ELFT> void LinkerScript<ELFT>::adjustSectionsAfterSorting() {
+  placeOrphanSections();
+
+  // If output section command doesn't specify any segments,
+  // and we haven't previously assigned any section to segment,
+  // then we simply assign section to the very first load segment.
+  // Below is an example of such linker script:
+  // PHDRS { seg PT_LOAD; }
+  // SECTIONS { .aaa : { *(.aaa) } }
+  std::vector<StringRef> DefPhdrs;
+  auto FirstPtLoad =
+      std::find_if(Opt.PhdrsCommands.begin(), Opt.PhdrsCommands.end(),
+                   [](const PhdrsCommand &Cmd) { return Cmd.Type == PT_LOAD; });
+  if (FirstPtLoad != Opt.PhdrsCommands.end())
+    DefPhdrs.push_back(FirstPtLoad->Name);
+
+  // Walk the commands and propagate the program headers to commands that don't
+  // explicitly specify them.
+  for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands) {
+    auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get());
+    if (!Cmd)
+      continue;
+    if (Cmd->Phdrs.empty())
+      Cmd->Phdrs = DefPhdrs;
+    else
+      DefPhdrs = Cmd->Phdrs;
+  }
 
   removeEmptyCommands();
 }
@@ -630,8 +659,6 @@ void LinkerScript<ELFT>::placeOrphanSections() {
 
 template <class ELFT>
 void LinkerScript<ELFT>::assignAddresses(std::vector<PhdrEntry<ELFT>> &Phdrs) {
-  placeOrphanSections();
-
   // Assign addresses as instructed by linker script SECTIONS sub-commands.
   Dot = 0;
 
@@ -711,7 +738,6 @@ std::vector<PhdrEntry<ELFT>> LinkerScript<ELFT>::createPhdrs() {
 
   // Process PHDRS and FILEHDR keywords because they are not
   // real output sections and cannot be added in the following loop.
-  std::vector<size_t> DefPhdrIds;
   for (const PhdrsCommand &Cmd : Opt.PhdrsCommands) {
     Ret.emplace_back(Cmd.Type, Cmd.Flags == UINT_MAX ? PF_R : Cmd.Flags);
     PhdrEntry<ELFT> &Phdr = Ret.back();
@@ -725,15 +751,6 @@ std::vector<PhdrEntry<ELFT>> LinkerScript<ELFT>::createPhdrs() {
       Phdr.H.p_paddr = Cmd.LMAExpr(0);
       Phdr.HasLMA = true;
     }
-
-    // If output section command doesn't specify any segments,
-    // and we haven't previously assigned any section to segment,
-    // then we simply assign section to the very first load segment.
-    // Below is an example of such linker script:
-    // PHDRS { seg PT_LOAD; }
-    // SECTIONS { .aaa : { *(.aaa) } }
-    if (DefPhdrIds.empty() && Phdr.H.p_type == PT_LOAD)
-      DefPhdrIds.push_back(Ret.size() - 1);
   }
 
   // Add output sections to program headers.
@@ -741,17 +758,12 @@ std::vector<PhdrEntry<ELFT>> LinkerScript<ELFT>::createPhdrs() {
     if (!(Sec->Flags & SHF_ALLOC))
       break;
 
-    std::vector<size_t> PhdrIds = getPhdrIndices(Sec->getName());
-    if (PhdrIds.empty())
-      PhdrIds = std::move(DefPhdrIds);
-
     // Assign headers specified by linker script
-    for (size_t Id : PhdrIds) {
+    for (size_t Id : getPhdrIndices(Sec->getName())) {
       Ret[Id].add(Sec);
       if (Opt.PhdrsCommands[Id].Flags == UINT_MAX)
         Ret[Id].H.p_flags |= Sec->getPhdrFlags();
     }
-    DefPhdrIds = std::move(PhdrIds);
   }
   return Ret;
 }

diff --git a/lld/ELF/LinkerScript.h b/lld/ELF/LinkerScript.h
index 6bd02f1..ce64526 100644 (file)
--- a/lld/ELF/LinkerScript.h
+++ b/lld/ELF/LinkerScript.h
@@ -221,6 +221,7 @@ public:
   void createSections(OutputSectionFactory<ELFT> &Factory);
   void removeEmptyCommands();
   void adjustSectionsBeforeSorting();
+  void adjustSectionsAfterSorting();
 
   std::vector<PhdrEntry<ELFT>> createPhdrs();
   bool ignoreInterpSection();

diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 9776f62..2117e47 100644 (file)
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -856,6 +856,8 @@ template <class ELFT> void Writer<ELFT>::sortSections() {
     std::rotate(BestPos, NonScriptI, NonScriptI + 1);
     ++NonScriptI;
   }
+
+  Script<ELFT>::X->adjustSectionsAfterSorting();
 }
 
 // Create output section objects and add them to OutputSections.

diff --git a/lld/test/ELF/linkerscript/Inputs/implicit-program-header.script b/lld/test/ELF/linkerscript/Inputs/implicit-program-header.script
new file mode 100644 (file)
index 0000000..27dbea8
--- /dev/null
+++ b/lld/test/ELF/linkerscript/Inputs/implicit-program-header.script
@@ -0,0 +1,12 @@
+PHDRS
+{
+       ph_write PT_LOAD FLAGS(2);
+       ph_exec  PT_LOAD FLAGS(1);
+}
+
+SECTIONS
+{
+  .bar : { *(.bar) } : ph_exec
+  .foo : { *(.foo) }
+  .text : { *(.text) } : ph_write
+}

diff --git a/lld/test/ELF/linkerscript/implicit-program-header.s b/lld/test/ELF/linkerscript/implicit-program-header.s
new file mode 100644 (file)
index 0000000..9598a6a
--- /dev/null
+++ b/lld/test/ELF/linkerscript/implicit-program-header.s
@@ -0,0 +1,13 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+# RUN: ld.lld -o %t1 --script %S/Inputs/implicit-program-header.script  \
+# RUN:   %t.o -shared
+# RUN: llvm-readobj -elf-output-style=GNU -l %t1 | FileCheck %s
+
+# CHECK:      Segment Sections...
+# CHECK-NEXT:   00     .text .dynsym .hash .dynstr .dynamic
+# CHECK-NEXT:   01     .foo
+
+.quad 0
+.section .foo,"ax"
+.quad 0