[lld] r307131 - [ELF] Extract allocateHeaders() from assignAddresses()

[Peter Smith via llvm-commits]

Author: psmith
Date: Wed Jul  5 02:12:54 2017
New Revision: 307131

URL: http://llvm.org/viewvc/llvm-project?rev=307131&view=rev
Log:
[ELF] Extract allocateHeaders() from assignAddresses()

The allocateHeaders() function is called at the end of assignAddresses(), it
decides whether the ELF header and program header table can be allocated to
a PT_LOAD program header. As the function alters state, it prevents
assignAddresses() from being called multiple times.

This change splits out the call to allocateHeaders() from assignAddresses()
this will permit assignAddresses() to be called while processing range
extension thunks without trying to allocateHeaders().

Differential Revision: https://reviews.llvm.org/D34344


Modified:
    lld/trunk/ELF/LinkerScript.cpp
    lld/trunk/ELF/LinkerScript.h
    lld/trunk/ELF/Writer.cpp

Modified: lld/trunk/ELF/LinkerScript.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LinkerScript.cpp?rev=307131&r1=307130&r2=307131&view=diff
==============================================================================
--- lld/trunk/ELF/LinkerScript.cpp (original)
+++ lld/trunk/ELF/LinkerScript.cpp Wed Jul  5 02:12:54 2017
@@ -783,10 +783,14 @@ void LinkerScript::processNonSectionComm
   }
 }
 
-static void
-allocateHeaders(std::vector<PhdrEntry> &Phdrs,
-                ArrayRef<OutputSectionCommand *> OutputSectionCommands,
-                uint64_t Min) {
+void LinkerScript::allocateHeaders(std::vector<PhdrEntry> &Phdrs) {
+  uint64_t Min = std::numeric_limits<uint64_t>::max();
+  for (OutputSectionCommand *Cmd : OutputSectionCommands) {
+    OutputSection *Sec = Cmd->Sec;
+    if (Sec->Flags & SHF_ALLOC)
+      Min = std::min<uint64_t>(Min, Sec->Addr);
+  }
+
   auto FirstPTLoad = llvm::find_if(
       Phdrs, [](const PhdrEntry &E) { return E.p_type == PT_LOAD; });
   if (FirstPTLoad == Phdrs.end())
@@ -826,7 +830,7 @@ allocateHeaders(std::vector<PhdrEntry> &
     Phdrs.erase(PhdrI);
 }
 
-void LinkerScript::assignAddresses(std::vector<PhdrEntry> &Phdrs) {
+void LinkerScript::assignAddresses() {
   // Assign addresses as instructed by linker script SECTIONS sub-commands.
   Dot = 0;
   ErrorOnMissingSection = true;
@@ -846,15 +850,6 @@ void LinkerScript::assignAddresses(std::
     auto *Cmd = cast<OutputSectionCommand>(Base);
     assignOffsets(Cmd);
   }
-
-  uint64_t MinVA = std::numeric_limits<uint64_t>::max();
-  for (OutputSectionCommand *Cmd : OutputSectionCommands) {
-    OutputSection *Sec = Cmd->Sec;
-    if (Sec->Flags & SHF_ALLOC)
-      MinVA = std::min<uint64_t>(MinVA, Sec->Addr);
-  }
-
-  allocateHeaders(Phdrs, OutputSectionCommands, MinVA);
 }
 
 // Creates program headers as instructed by PHDRS linker script command.

Modified: lld/trunk/ELF/LinkerScript.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LinkerScript.h?rev=307131&r1=307130&r2=307131&view=diff
==============================================================================
--- lld/trunk/ELF/LinkerScript.h (original)
+++ lld/trunk/ELF/LinkerScript.h Wed Jul  5 02:12:54 2017
@@ -281,8 +281,8 @@ public:
   void assignOffsets(OutputSectionCommand *Cmd);
   void createOrphanCommands();
   void processNonSectionCommands();
-  void assignAddresses(std::vector<PhdrEntry> &Phdrs);
-
+  void assignAddresses();
+  void allocateHeaders(std::vector<PhdrEntry> &Phdrs);
   void addSymbol(SymbolAssignment *Cmd);
   void processCommands(OutputSectionFactory &Factory);
 

Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=307131&r1=307130&r2=307131&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Wed Jul  5 02:12:54 2017
@@ -217,7 +217,8 @@ template <class ELFT> void Writer<ELFT>:
       OutputSectionCommands.begin(), OutputSectionCommands.end(),
       [](OutputSectionCommand *Cmd) { Cmd->maybeCompress<ELFT>(); });
 
-  Script->assignAddresses(Phdrs);
+  Script->assignAddresses();
+  Script->allocateHeaders(Phdrs);
 
   // Remove empty PT_LOAD to avoid causing the dynamic linker to try to mmap a
   // 0 sized region. This has to be done late since only after assignAddresses