[mips] Put some MIPS-specific sections to separate segments

Three MIPS-specific sections `.reginfo`, `.MIPS.options`, and `.MIPS.abiflags` are used by loader to read their contents and setup environment for running a program. Loader looks up these data in the corresponding segments: `PT_MIPS_REGINFO`, `PT_MIPS_OPTIONS`, and `PT_MIPS_ABIFLAGS` respectively. This patch put these sections to separate segments like we do already for ARM `SHT_ARM_EXIDX` section. Differential Revision: http://reviews.llvm.org/D58381 llvm-svn: 354468
llvm · Feb 20, 2019 · 14b0981 · 14b0981
1 parent 68171e3
commit 14b0981
Show file tree

Hide file tree

Showing 4 changed files with 68 additions and 23 deletions.
diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
@@ -60,7 +60,8 @@ template <class ELFT> class Writer {
 
   std::vector<PhdrEntry *> createPhdrs();
   void removeEmptyPTLoad();
-  void addPtArmExid(std::vector<PhdrEntry *> &Phdrs);
+  void addPhdrForSection(std::vector<PhdrEntry *> &Phdrs, unsigned ShType,
+                         unsigned PType, unsigned PFlags);
   void assignFileOffsets();
   void assignFileOffsetsBinary();
   void setPhdrs();
@@ -1757,7 +1758,16 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
   // image base and the dynamic section on mips includes the image base.
   if (!Config->Relocatable && !Config->OFormatBinary) {
     Phdrs = Script->hasPhdrsCommands() ? Script->createPhdrs() : createPhdrs();
-    addPtArmExid(Phdrs);
+    if (Config->EMachine == EM_ARM) {
+      // PT_ARM_EXIDX is the ARM EHABI equivalent of PT_GNU_EH_FRAME
+      addPhdrForSection(Phdrs, SHT_ARM_EXIDX, PT_ARM_EXIDX, PF_R);
+    }
+    if (Config->EMachine == EM_MIPS) {
+      // Add separate segments for MIPS-specific sections.
+      addPhdrForSection(Phdrs, SHT_MIPS_REGINFO, PT_MIPS_REGINFO, PF_R);
+      addPhdrForSection(Phdrs, SHT_MIPS_OPTIONS, PT_MIPS_OPTIONS, PF_R);
+      addPhdrForSection(Phdrs, SHT_MIPS_ABIFLAGS, PT_MIPS_ABIFLAGS, PF_R);
+    }
     Out::ProgramHeaders->Size = sizeof(Elf_Phdr) * Phdrs.size();
 
     // Find the TLS segment. This happens before the section layout loop so that
@@ -2053,19 +2063,17 @@ template <class ELFT> std::vector<PhdrEntry *> Writer<ELFT>::createPhdrs() {
 }
 
 template <class ELFT>
-void Writer<ELFT>::addPtArmExid(std::vector<PhdrEntry *> &Phdrs) {
-  if (Config->EMachine != EM_ARM)
-    return;
-  auto I = llvm::find_if(OutputSections, [](OutputSection *Cmd) {
-    return Cmd->Type == SHT_ARM_EXIDX;
-  });
+void Writer<ELFT>::addPhdrForSection(std::vector<PhdrEntry *> &Phdrs,
+                                     unsigned ShType, unsigned PType,
+                                     unsigned PFlags) {
+  auto I = llvm::find_if(
+      OutputSections, [=](OutputSection *Cmd) { return Cmd->Type == ShType; });
   if (I == OutputSections.end())
     return;
 
-  // PT_ARM_EXIDX is the ARM EHABI equivalent of PT_GNU_EH_FRAME
-  PhdrEntry *ARMExidx = make<PhdrEntry>(PT_ARM_EXIDX, PF_R);
-  ARMExidx->add(*I);
-  Phdrs.push_back(ARMExidx);
+  PhdrEntry *Entry = make<PhdrEntry>(PType, PFlags);
+  Entry->add(*I);
+  Phdrs.push_back(Entry);
 }
 
 // The first section of each PT_LOAD, the first section in PT_GNU_RELRO and the

diff --git a/lld/test/ELF/basic-mips.s b/lld/test/ELF/basic-mips.s
@@ -34,7 +34,7 @@ __start:
 # CHECK-NEXT:   ]
 # CHECK-NEXT:   HeaderSize: 52
 # CHECK-NEXT:   ProgramHeaderEntrySize: 32
-# CHECK-NEXT:   ProgramHeaderCount: 5
+# CHECK-NEXT:   ProgramHeaderCount: 7
 # CHECK-NEXT:   SectionHeaderEntrySize: 40
 # CHECK-NEXT:   SectionHeaderCount: 11
 # CHECK-NEXT:   StringTableSectionIndex: 9
@@ -61,8 +61,8 @@ __start:
 # CHECK-NEXT:     Flags [ (0x2)
 # CHECK-NEXT:       SHF_ALLOC (0x2)
 # CHECK-NEXT:     ]
-# CHECK-NEXT:     Address: 0x100D8
-# CHECK-NEXT:     Offset: 0xD8
+# CHECK-NEXT:     Address: 0x10118
+# CHECK-NEXT:     Offset: 0x118
 # CHECK-NEXT:     Size: 24
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
@@ -76,8 +76,8 @@ __start:
 # CHECK-NEXT:     Flags [ (0x2)
 # CHECK-NEXT:       SHF_ALLOC (0x2)
 # CHECK-NEXT:     ]
-# CHECK-NEXT:     Address: 0x100F0
-# CHECK-NEXT:     Offset: 0xF0
+# CHECK-NEXT:     Address: 0x10130
+# CHECK-NEXT:     Offset: 0x130
 # CHECK-NEXT:     Size: 24
 # CHECK-NEXT:     Link: 0
 # CHECK-NEXT:     Info: 0
@@ -245,8 +245,8 @@ __start:
 # CHECK-NEXT:     Offset: 0x34
 # CHECK-NEXT:     VirtualAddress: 0x10034
 # CHECK-NEXT:     PhysicalAddress: 0x10034
-# CHECK-NEXT:     FileSize: 160
-# CHECK-NEXT:     MemSize: 160
+# CHECK-NEXT:     FileSize: 224
+# CHECK-NEXT:     MemSize: 224
 # CHECK-NEXT:     Flags [ (0x4)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:     ]
@@ -257,8 +257,8 @@ __start:
 # CHECK-NEXT:     Offset: 0x0
 # CHECK-NEXT:     VirtualAddress: 0x10000
 # CHECK-NEXT:     PhysicalAddress: 0x10000
-# CHECK-NEXT:     FileSize: 264
-# CHECK-NEXT:     MemSize: 264
+# CHECK-NEXT:     FileSize: 328
+# CHECK-NEXT:     MemSize: 328
 # CHECK-NEXT:     Flags [ (0x4)
 # CHECK-NEXT:       PF_R (0x4)
 # CHECK-NEXT:     ]
@@ -303,4 +303,28 @@ __start:
 # CHECK-NEXT:     ]
 # CHECK-NEXT:     Alignment: 0
 # CHECK-NEXT:   }
+# CHECK-NEXT:   ProgramHeader {
+# CHECK-NEXT:     Type: PT_MIPS_REGINFO
+# CHECK-NEXT:     Offset: 0x130
+# CHECK-NEXT:     VirtualAddress: 0x10130
+# CHECK-NEXT:     PhysicalAddress: 0x10130
+# CHECK-NEXT:     FileSize: 24
+# CHECK-NEXT:     MemSize: 24
+# CHECK-NEXT:     Flags [ (0x4)
+# CHECK-NEXT:       PF_R (0x4)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Alignment: 4
+# CHECK-NEXT:   }
+# CHECK-NEXT:   ProgramHeader {
+# CHECK-NEXT:     Type: PT_MIPS_ABIFLAGS
+# CHECK-NEXT:     Offset: 0x118
+# CHECK-NEXT:     VirtualAddress: 0x10118
+# CHECK-NEXT:     PhysicalAddress: 0x10118
+# CHECK-NEXT:     FileSize: 24
+# CHECK-NEXT:     MemSize: 24
+# CHECK-NEXT:     Flags [ (0x4)
+# CHECK-NEXT:       PF_R (0x4)
+# CHECK-NEXT:     ]
+# CHECK-NEXT:     Alignment: 8
+# CHECK-NEXT:   }
 # CHECK-NEXT: ]
diff --git a/lld/test/ELF/mips-got-string.s b/lld/test/ELF/mips-got-string.s
@@ -7,7 +7,7 @@
 
 # CHECK:      Symbol {
 # CHECK:        Name: $.str
-# CHECK-NEXT:   Value: 0x1B1
+# CHECK-NEXT:   Value: 0x1F1
 # CHECK:      }
 
 # CHECK:      Local entries [

diff --git a/lld/test/ELF/mips-options.s b/lld/test/ELF/mips-options.s
@@ -8,7 +8,7 @@
 # RUN:          . = 0x100000000; \
 # RUN:          .got  : { *(.got) } }" > %t.rel.script
 # RUN: ld.lld %t1.o %t2.o --gc-sections --script %t.rel.script -shared -o %t.so
-# RUN: llvm-readobj -symbols -mips-options %t.so | FileCheck %s
+# RUN: llvm-readobj -program-headers -symbols -mips-options %t.so | FileCheck %s
 
   .text
   .globl  __start
@@ -18,6 +18,19 @@ __start:
 # CHECK:      Name: _gp
 # CHECK-NEXT: Value: 0x[[GP:[0-9A-F]+]]
 
+# CHECK:      ProgramHeader {
+# CHECK:        Type: PT_MIPS_OPTIONS
+# CHECK-NEXT:   Offset:
+# CHECK-NEXT:   VirtualAddress:
+# CHECK-NEXT:   PhysicalAddress:
+# CHECK-NEXT:   FileSize:
+# CHECK-NEXT:   MemSize:
+# CHECK-NEXT:   Flags [
+# CHECK-NEXT:     PF_R
+# CHECK-NEXT:   ]
+# CHECK-NEXT:   Alignment: 8
+# CHECK-NEXT: }
+
 # CHECK:      MIPS Options {
 # CHECK-NEXT:   ODK_REGINFO {
 # CHECK-NEXT:     GP: 0x[[GP]]