[PATCH] D113768: [ELF] Do not try to assign a memory region to a non-allocatable section

[Igor Kudrin via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG66691de94cd7: [ELF] Do not try to assign a memory region to a non-allocatable section (authored by ikudrin).

Changed prior to commit:
  https://reviews.llvm.org/D113768?vs=386835&id=387167#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D113768/new/

https://reviews.llvm.org/D113768

Files:
  lld/ELF/LinkerScript.cpp
  lld/test/ELF/linkerscript/memory-nonalloc.test


Index: lld/test/ELF/linkerscript/memory-nonalloc.test
===================================================================
--- /dev/null
+++ lld/test/ELF/linkerscript/memory-nonalloc.test
@@ -0,0 +1,48 @@
+REQUIRES: x86
+
+RUN: split-file %s %ts
+RUN: llvm-mc -filetype=obj -triple=x86_64 %ts/s -o %t.o
+
+## Check that a non-allocatable section is not assigned to a memory region by
+## matching the section/region properties. Previously, that could lead to an
+## "error: section '.nonalloc' will not fit in region 'RAM'".
+
+RUN: ld.lld %t.o -T %ts/t --fatal-warnings -o /dev/null
+
+## Check that an explicit assignment is ignored for a non-allocatable section.
+## Previously, that also could lead to the same error.
+
+RUN: ld.lld %t.o -T %ts/t2 -o /dev/null 2>&1 | FileCheck %s --check-prefix=WARN
+
+WARN: warning: ignoring memory region assignment for non-allocatable section '.nonalloc'
+
+#--- s
+  .global _start
+_start:
+
+  ## Note: a "writable" section is used because lld does not fully support
+  ## memory region attribute "r" at the moment.
+  .section .nonalloc,"w"
+  .zero 0x1000
+
+#--- t
+MEMORY
+{
+  RAM (rwx) : ORIGIN = 0x8000, LENGTH = 0x100
+}
+
+SECTIONS
+{
+  .nonalloc : { *(.nonalloc) }
+}
+
+#--- t2
+MEMORY
+{
+  RAM (rwx) : ORIGIN = 0x8000, LENGTH = 0x100
+}
+
+SECTIONS
+{
+  .nonalloc : { *(.nonalloc) } > RAM
+}
Index: lld/ELF/LinkerScript.cpp
===================================================================
--- lld/ELF/LinkerScript.cpp
+++ lld/ELF/LinkerScript.cpp
@@ -887,6 +887,14 @@
 // subsequent call of this method.
 std::pair<MemoryRegion *, MemoryRegion *>
 LinkerScript::findMemoryRegion(OutputSection *sec, MemoryRegion *hint) {
+  // Non-allocatable sections are not part of the process image.
+  if (!(sec->flags & SHF_ALLOC)) {
+    if (!sec->memoryRegionName.empty())
+      warn("ignoring memory region assignment for non-allocatable section '" +
+           sec->name + "'");
+    return {nullptr, nullptr};
+  }
+
   // If a memory region name was specified in the output section command,
   // then try to find that region first.
   if (!sec->memoryRegionName.empty()) {
@@ -902,8 +910,8 @@
   if (memoryRegions.empty())
     return {nullptr, nullptr};
 
-  // An allocatable orphan section should continue the previous memory region.
-  if (sec->sectionIndex == UINT32_MAX && (sec->flags & SHF_ALLOC) && hint)
+  // An orphan section should continue the previous memory region.
+  if (sec->sectionIndex == UINT32_MAX && hint)
     return {hint, hint};
 
   // See if a region can be found by matching section flags.
@@ -914,8 +922,7 @@
   }
 
   // Otherwise, no suitable region was found.
-  if (sec->flags & SHF_ALLOC)
-    error("no memory region specified for section '" + sec->name + "'");
+  error("no memory region specified for section '" + sec->name + "'");
   return {nullptr, nullptr};
 }
 


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