[ELF] - Linkerscript: create multiple output sections for inputs with different attri...

Previously we combined sections by name if linkerscript was used.
For that we had to disable SHF_MERGE handling temporarily, but then
found that implementing it properly will require additional complexity layers like
subsections or something.
At the same time looks we can live with multiple output sections approach for now.
That patch do this change.

Differential revision: https://reviews.llvm.org/D24127

llvm-svn: 280801

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 8e0016a231098cc8ec2f160a9a03103b7359335b..a6fbe64d5ee2a3b626ac5680f518793dfd65f0e2 100644 (file)
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -242,14 +242,15 @@ void LinkerScript<ELFT>::createSections(OutputSectionFactory<ELFT> &Factory) {
       if (V.empty())
         continue;
 
-      OutputSectionBase<ELFT> *OutSec;
-      bool IsNew;
-      std::tie(OutSec, IsNew) = Factory.create(V.front(), Cmd->Name);
-      if (IsNew)
-        OutputSections->push_back(OutSec);
-
-      uint32_t Subalign = Cmd->SubalignExpr ? Cmd->SubalignExpr(0) : 0;
       for (InputSectionBase<ELFT> *Sec : V) {
+        OutputSectionBase<ELFT> *OutSec;
+        bool IsNew;
+        std::tie(OutSec, IsNew) = Factory.create(Sec, Cmd->Name);
+        if (IsNew)
+          OutputSections->push_back(OutSec);
+
+        uint32_t Subalign = Cmd->SubalignExpr ? Cmd->SubalignExpr(0) : 0;
+
         if (Subalign)
           Sec->Alignment = Subalign;
         OutSec->addSection(Sec);
@@ -368,16 +369,15 @@ void assignOffsets(OutputSectionCommand *Cmd, OutputSectionBase<ELFT> *Sec) {
 }
 
 template <class ELFT>
-static OutputSectionBase<ELFT> *
-findSection(OutputSectionCommand &Cmd,
-            ArrayRef<OutputSectionBase<ELFT> *> Sections) {
-  for (OutputSectionBase<ELFT> *Sec : Sections) {
-    if (Sec->getName() != Cmd.Name)
-      continue;
-    if (checkConstraint(Sec->getFlags(), Cmd.Constraint))
-      return Sec;
-  }
-  return nullptr;
+static std::vector<OutputSectionBase<ELFT> *>
+findSections(OutputSectionCommand &Cmd,
+             ArrayRef<OutputSectionBase<ELFT> *> Sections) {
+  std::vector<OutputSectionBase<ELFT> *> Ret;
+  for (OutputSectionBase<ELFT> *Sec : Sections)
+    if (Sec->getName() == Cmd.Name &&
+        checkConstraint(Sec->getFlags(), Cmd.Constraint))
+      Ret.push_back(Sec);
+  return Ret;
 }
 
 template <class ELFT> void LinkerScript<ELFT>::assignAddresses() {
@@ -413,35 +413,35 @@ template <class ELFT> void LinkerScript<ELFT>::assignAddresses() {
     }
 
     auto *Cmd = cast<OutputSectionCommand>(Base.get());
-    OutputSectionBase<ELFT> *Sec = findSection<ELFT>(*Cmd, *OutputSections);
-    if (!Sec)
-      continue;
+    for (OutputSectionBase<ELFT> *Sec :
+         findSections<ELFT>(*Cmd, *OutputSections)) {
 
-    if (Cmd->AddrExpr)
-      Dot = Cmd->AddrExpr(Dot);
+      if (Cmd->AddrExpr)
+        Dot = Cmd->AddrExpr(Dot);
 
-    if (Cmd->AlignExpr)
-      Sec->updateAlignment(Cmd->AlignExpr(Dot));
+      if (Cmd->AlignExpr)
+        Sec->updateAlignment(Cmd->AlignExpr(Dot));
 
-    if ((Sec->getFlags() & SHF_TLS) && Sec->getType() == SHT_NOBITS) {
-      uintX_t TVA = Dot + ThreadBssOffset;
-      TVA = alignTo(TVA, Sec->getAlignment());
-      Sec->setVA(TVA);
-      assignOffsets(Cmd, Sec);
-      ThreadBssOffset = TVA - Dot + Sec->getSize();
-      continue;
-    }
+      if ((Sec->getFlags() & SHF_TLS) && Sec->getType() == SHT_NOBITS) {
+        uintX_t TVA = Dot + ThreadBssOffset;
+        TVA = alignTo(TVA, Sec->getAlignment());
+        Sec->setVA(TVA);
+        assignOffsets(Cmd, Sec);
+        ThreadBssOffset = TVA - Dot + Sec->getSize();
+        continue;
+      }
 
-    if (!(Sec->getFlags() & SHF_ALLOC)) {
+      if (!(Sec->getFlags() & SHF_ALLOC)) {
+        assignOffsets(Cmd, Sec);
+        continue;
+      }
+
+      Dot = alignTo(Dot, Sec->getAlignment());
+      Sec->setVA(Dot);
       assignOffsets(Cmd, Sec);
-      continue;
+      MinVA = std::min(MinVA, Dot);
+      Dot += Sec->getSize();
     }
-
-    Dot = alignTo(Dot, Sec->getAlignment());
-    Sec->setVA(Dot);
-    assignOffsets(Cmd, Sec);
-    MinVA = std::min(MinVA, Dot);
-    Dot += Sec->getSize();
   }
 
   // ELF and Program headers need to be right before the first section in

diff --git a/lld/test/ELF/linkerscript/merge-sections.s b/lld/test/ELF/linkerscript/merge-sections.s
deleted file mode 100644 (file)
index bb3849a..0000000
--- a/lld/test/ELF/linkerscript/merge-sections.s
+++ /dev/null
@@ -1,28 +0,0 @@
-# REQUIRES: x86
-# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
-
-# RUN: echo "SECTIONS { .foo : { *(.foo.*) } }" > %t.script
-# RUN: ld.lld -o %t1 --script %t.script %t
-# RUN: llvm-objdump -s %t1 | FileCheck %s
-# CHECK:      Contents of section .foo:
-# CHECK-NEXT:  0158 01000000 02000000 00000000 73686f72  ............shor
-# CHECK-NEXT:  0168 7420756e 7369676e 65642069 6e7400    t unsigned int.
-
-.global _start
-_start:
-  nop
-
-.section .foo.1, "aw"
-writable:
- .long 1
-
-.section .foo.2, "aM",@progbits,1
-readable:
- .long 2
-
-.section .foo.3, "awx"
- .long 0
-
-.section .foo.4, "MS",@progbits,1
-.LASF2:
- .string "short unsigned int"

diff --git a/lld/test/ELF/linkerscript/phdrs.s b/lld/test/ELF/linkerscript/phdrs.s
index 775e002506b4ec48295c3ead5ff7116cd1ee3603..cd6bf82b55b81b5d03a51c02802267df4341c725 100644 (file)
--- a/lld/test/ELF/linkerscript/phdrs.s
+++ b/lld/test/ELF/linkerscript/phdrs.s
@@ -17,8 +17,9 @@
 # CHECK-NEXT:    PhysicalAddress: 0x10000000
 # CHECK-NEXT:    FileSize: 521
 # CHECK-NEXT:    MemSize: 521
-# CHECK-NEXT:    Flags [ (0x5)
+# CHECK-NEXT:    Flags [ (0x7)
 # CHECK-NEXT:      PF_R (0x4)
+# CHECK-NEXT:      PF_W (0x2)
 # CHECK-NEXT:      PF_X (0x1)
 # CHECK-NEXT:    ]
 

diff --git a/lld/test/ELF/linkerscript/repsection-va.s b/lld/test/ELF/linkerscript/repsection-va.s
index 29ecdf84a8b79f1aab165700d0637e706a69b90d..4feeaa0e1c38390bd95ed1d6e298214f5dc7081d 100644 (file)
--- a/lld/test/ELF/linkerscript/repsection-va.s
+++ b/lld/test/ELF/linkerscript/repsection-va.s
@@ -7,8 +7,9 @@
 # CHECK:      Sections:
 # CHECK-NEXT: Idx Name          Size      Address          Type
 # CHECK-NEXT:   0               00000000 0000000000000000
-# CHECK-NEXT:   1 .foo          00000008 0000000000000120 DATA
-# CHECK-NEXT:   2 .text         00000001 0000000000000128 TEXT DATA
+# CHECK-NEXT:   1 .foo          00000004 0000000000000158 DATA
+# CHECK-NEXT:   2 .foo          00000004 000000000000015c DATA
+# CHECK-NEXT:   3 .text         00000001 0000000000000160 TEXT DATA
 
 .global _start
 _start: