Vendor import of lld release_70 branch r339355:

https://llvm.org/svn/llvm-project/lld/branches/release_70@339355

COFF/InputFiles.cpp

@@ -205,7 +205,13 @@ SectionChunk *ObjFile::readSection(uint32_t SectionNumber,
 
 void ObjFile::readAssociativeDefinition(
     COFFSymbolRef Sym, const coff_aux_section_definition *Def) {
-  SectionChunk *Parent = SparseChunks[Def->getNumber(Sym.isBigObj())];
+  readAssociativeDefinition(Sym, Def, Def->getNumber(Sym.isBigObj()));
+}
+
+void ObjFile::readAssociativeDefinition(COFFSymbolRef Sym,
+                                        const coff_aux_section_definition *Def,
+                                        uint32_t ParentSection) {
+  SectionChunk *Parent = SparseChunks[ParentSection];
 
   // If the parent is pending, it probably means that its section definition
   // appears after us in the symbol table. Leave the associated section as
@@ -225,6 +231,35 @@ void ObjFile::readAssociativeDefinition(
   }
 }
 
+void ObjFile::recordPrevailingSymbolForMingw(
+    COFFSymbolRef Sym, DenseMap<StringRef, uint32_t> &PrevailingSectionMap) {
+  // For comdat symbols in executable sections, where this is the copy
+  // of the section chunk we actually include instead of discarding it,
+  // add the symbol to a map to allow using it for implicitly
+  // associating .[px]data$<func> sections to it.
+  int32_t SectionNumber = Sym.getSectionNumber();
+  SectionChunk *SC = SparseChunks[SectionNumber];
+  if (SC && SC->getOutputCharacteristics() & IMAGE_SCN_MEM_EXECUTE) {
+    StringRef Name;
+    COFFObj->getSymbolName(Sym, Name);
+    PrevailingSectionMap[Name] = SectionNumber;
+  }
+}
+
+void ObjFile::maybeAssociateSEHForMingw(
+    COFFSymbolRef Sym, const coff_aux_section_definition *Def,
+    const DenseMap<StringRef, uint32_t> &PrevailingSectionMap) {
+  StringRef Name;
+  COFFObj->getSymbolName(Sym, Name);
+  if (Name.consume_front(".pdata$") || Name.consume_front(".xdata$")) {
+    // For MinGW, treat .[px]data$<func> as implicitly associative to
+    // the symbol <func>.
+    auto ParentSym = PrevailingSectionMap.find(Name);
+    if (ParentSym != PrevailingSectionMap.end())
+      readAssociativeDefinition(Sym, Def, ParentSym->second);
+  }
+}
+
 Symbol *ObjFile::createRegular(COFFSymbolRef Sym) {
   SectionChunk *SC = SparseChunks[Sym.getSectionNumber()];
   if (Sym.isExternal()) {
@@ -248,19 +283,24 @@ void ObjFile::initializeSymbols() {
   std::vector<uint32_t> PendingIndexes;
   PendingIndexes.reserve(NumSymbols);
 
+  DenseMap<StringRef, uint32_t> PrevailingSectionMap;
   std::vector<const coff_aux_section_definition *> ComdatDefs(
       COFFObj->getNumberOfSections() + 1);
 
   for (uint32_t I = 0; I < NumSymbols; ++I) {
     COFFSymbolRef COFFSym = check(COFFObj->getSymbol(I));
+    bool PrevailingComdat;
     if (COFFSym.isUndefined()) {
       Symbols[I] = createUndefined(COFFSym);
     } else if (COFFSym.isWeakExternal()) {
       Symbols[I] = createUndefined(COFFSym);
       uint32_t TagIndex = COFFSym.getAux<coff_aux_weak_external>()->TagIndex;
       WeakAliases.emplace_back(Symbols[I], TagIndex);
-    } else if (Optional<Symbol *> OptSym = createDefined(COFFSym, ComdatDefs)) {
+    } else if (Optional<Symbol *> OptSym =
+                   createDefined(COFFSym, ComdatDefs, PrevailingComdat)) {
       Symbols[I] = *OptSym;
+      if (Config->MinGW && PrevailingComdat)
+        recordPrevailingSymbolForMingw(COFFSym, PrevailingSectionMap);
     } else {
       // createDefined() returns None if a symbol belongs to a section that
       // was pending at the point when the symbol was read. This can happen in
@@ -278,9 +318,12 @@ void ObjFile::initializeSymbols() {
 
   for (uint32_t I : PendingIndexes) {
     COFFSymbolRef Sym = check(COFFObj->getSymbol(I));
-    if (auto *Def = Sym.getSectionDefinition())
+    if (auto *Def = Sym.getSectionDefinition()) {
       if (Def->Selection == IMAGE_COMDAT_SELECT_ASSOCIATIVE)
         readAssociativeDefinition(Sym, Def);
+      else if (Config->MinGW)
+        maybeAssociateSEHForMingw(Sym, Def, PrevailingSectionMap);
+    }
     if (SparseChunks[Sym.getSectionNumber()] == PendingComdat) {
       StringRef Name;
       COFFObj->getSymbolName(Sym, Name);
@@ -306,7 +349,9 @@ Symbol *ObjFile::createUndefined(COFFSymbolRef Sym) {
 
 Optional<Symbol *> ObjFile::createDefined(
     COFFSymbolRef Sym,
-    std::vector<const coff_aux_section_definition *> &ComdatDefs) {
+    std::vector<const coff_aux_section_definition *> &ComdatDefs,
+    bool &Prevailing) {
+  Prevailing = false;
   auto GetName = [&]() {
     StringRef S;
     COFFObj->getSymbolName(Sym, S);
@@ -352,7 +397,6 @@ Optional<Symbol *> ObjFile::createDefined(
   if (const coff_aux_section_definition *Def = ComdatDefs[SectionNumber]) {
     ComdatDefs[SectionNumber] = nullptr;
     Symbol *Leader;
-    bool Prevailing;
     if (Sym.isExternal()) {
       std::tie(Leader, Prevailing) =
           Symtab->addComdat(this, GetName(), Sym.getGeneric());

COFF/InputFiles.h

@@ -13,6 +13,7 @@
 #include "Config.h"
 #include "lld/Common/LLVM.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/LTO/LTO.h"
 #include "llvm/Object/Archive.h"
@@ -157,10 +158,24 @@ class ObjFile : public InputFile {
       COFFSymbolRef COFFSym,
       const llvm::object::coff_aux_section_definition *Def);
 
+  void readAssociativeDefinition(
+      COFFSymbolRef COFFSym,
+      const llvm::object::coff_aux_section_definition *Def,
+      uint32_t ParentSection);
+
+  void recordPrevailingSymbolForMingw(
+      COFFSymbolRef COFFSym,
+      llvm::DenseMap<StringRef, uint32_t> &PrevailingSectionMap);
+
+  void maybeAssociateSEHForMingw(
+      COFFSymbolRef Sym, const llvm::object::coff_aux_section_definition *Def,
+      const llvm::DenseMap<StringRef, uint32_t> &PrevailingSectionMap);
+
   llvm::Optional<Symbol *>
   createDefined(COFFSymbolRef Sym,
                 std::vector<const llvm::object::coff_aux_section_definition *>
-                    &ComdatDefs);
+                    &ComdatDefs,
+                bool &PrevailingComdat);
   Symbol *createRegular(COFFSymbolRef Sym);
   Symbol *createUndefined(COFFSymbolRef Sym);
 

ELF/LinkerScript.cpp

@@ -116,7 +116,8 @@ void LinkerScript::expandMemoryRegions(uint64_t Size) {
   if (Ctx->MemRegion)
     expandMemoryRegion(Ctx->MemRegion, Size, Ctx->MemRegion->Name,
                        Ctx->OutSec->Name);
-  if (Ctx->LMARegion)
+  // Only expand the LMARegion if it is different from MemRegion.
+  if (Ctx->LMARegion && Ctx->MemRegion != Ctx->LMARegion)
     expandMemoryRegion(Ctx->LMARegion, Size, Ctx->LMARegion->Name,
                        Ctx->OutSec->Name);
 }
@@ -750,6 +751,13 @@ MemoryRegion *LinkerScript::findMemoryRegion(OutputSection *Sec) {
   return nullptr;
 }
 
+static OutputSection *findFirstSection(PhdrEntry *Load) {
+  for (OutputSection *Sec : OutputSections)
+    if (Sec->PtLoad == Load)
+      return Sec;
+  return nullptr;
+}
+
 // This function assigns offsets to input sections and an output section
 // for a single sections command (e.g. ".text { *(.text); }").
 void LinkerScript::assignOffsets(OutputSection *Sec) {
@@ -775,8 +783,11 @@ void LinkerScript::assignOffsets(OutputSection *Sec) {
   // will set the LMA such that the difference between VMA and LMA for the
   // section is the same as the preceding output section in the same region
   // https://sourceware.org/binutils/docs-2.20/ld/Output-Section-LMA.html
+  // This, however, should only be done by the first "non-header" section
+  // in the segment.
   if (PhdrEntry *L = Ctx->OutSec->PtLoad)
-    L->LMAOffset = Ctx->LMAOffset;
+    if (Sec == findFirstSection(L))
+      L->LMAOffset = Ctx->LMAOffset;
 
   // We can call this method multiple times during the creation of
   // thunks and want to start over calculation each time.
@@ -953,13 +964,6 @@ void LinkerScript::adjustSectionsAfterSorting() {
   }
 }
 
-static OutputSection *findFirstSection(PhdrEntry *Load) {
-  for (OutputSection *Sec : OutputSections)
-    if (Sec->PtLoad == Load)
-      return Sec;
-  return nullptr;
-}
-
 static uint64_t computeBase(uint64_t Min, bool AllocateHeaders) {
   // If there is no SECTIONS or if the linkerscript is explicit about program
   // headers, do our best to allocate them.

ELF/Writer.cpp

@@ -1815,12 +1815,14 @@ template <class ELFT> std::vector<PhdrEntry *> Writer<ELFT>::createPhdrs() {
     // Segments are contiguous memory regions that has the same attributes
     // (e.g. executable or writable). There is one phdr for each segment.
     // Therefore, we need to create a new phdr when the next section has
-    // different flags or is loaded at a discontiguous address using AT linker
-    // script command. At the same time, we don't want to create a separate
-    // load segment for the headers, even if the first output section has
-    // an AT attribute.
+    // different flags or is loaded at a discontiguous address or memory
+    // region using AT or AT> linker script command, respectively. At the same
+    // time, we don't want to create a separate load segment for the headers,
+    // even if the first output section has an AT or AT> attribute.
     uint64_t NewFlags = computeFlags(Sec->getPhdrFlags());
-    if ((Sec->LMAExpr && Load->LastSec != Out::ProgramHeaders) ||
+    if (((Sec->LMAExpr ||
+          (Sec->LMARegion && (Sec->LMARegion != Load->FirstSec->LMARegion))) &&
+         Load->LastSec != Out::ProgramHeaders) ||
         Sec->MemRegion != Load->FirstSec->MemRegion || Flags != NewFlags) {
 
       Load = AddHdr(PT_LOAD, NewFlags);

test/COFF/Inputs/associative-comdat-mingw-2.s

@@ -0,0 +1,34 @@
+        .section        .xdata$foo,"dr"
+        .linkonce       discard
+        .p2align        3
+        .long           42
+
+        .section        .xdata$bar,"dr"
+        .linkonce       discard
+        .p2align        3
+        .long           43
+
+        .section        .xdata$baz,"dr"
+        .linkonce       discard
+        .p2align        3
+        .long           44
+
+        .def            foo;
+        .scl            2;
+        .type           32;
+        .endef
+        .section        .text$foo,"xr",discard,foo
+        .globl          foo
+        .p2align        4
+foo:
+        ret
+
+        .def            bar;
+        .scl            2;
+        .type           32;
+        .endef
+        .section        .text$bar,"xr",discard,bar
+        .globl          bar
+        .p2align        4
+bar:
+        ret

test/COFF/associative-comdat-mingw.s

@@ -0,0 +1,73 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -triple=x86_64-windows-gnu %s -filetype=obj -o %t1.obj
+# RUN: llvm-mc -triple=x86_64-windows-gnu %S/Inputs/associative-comdat-mingw-2.s -filetype=obj -o %t2.obj
+
+# RUN: lld-link -lldmingw -entry:main %t1.obj %t2.obj -out:%t.gc.exe -verbose
+# RUN: llvm-readobj -sections %t.gc.exe | FileCheck %s
+
+# CHECK: Sections [
+# CHECK:   Section {
+# CHECK:     Number: 2
+# CHECK-LABEL:     Name: .rdata (2E 72 64 61 74 61 00 00)
+#             This is the critical check to show that only *one* definition of
+#             .xdata$foo was retained. This *must* be 4.
+#             Make sure that no other .xdata sections get included, which would
+#             increase the size here.
+# CHECK-NEXT:     VirtualSize: 0x4
+
+        .text
+        .def            main;
+        .scl            2;
+        .type           32;
+        .endef
+        .globl          main
+        .p2align        4, 0x90
+main:
+        call            foo
+        retq
+
+# Defines .text$foo (which has a leader symbol and is referenced like
+# normally), and .xdata$foo (which lacks a leader symbol, which normally
+# would be declared associative to the symbol foo).
+# .xdata$foo should be implicitly treated as associative to foo and brought
+# in, while .xdata$bar, implicitly associative to bar, not included, and
+# .xdata$baz not included since there's no symbol baz.
+
+# GNU binutils ld doesn't do this at all, but always includes all .xdata/.pdata
+# comdat sections, even if --gc-sections is used.
+
+        .section        .xdata$foo,"dr"
+        .linkonce       discard
+        .p2align        3
+        .long           42
+
+        .section        .xdata$bar,"dr"
+        .linkonce       discard
+        .p2align        3
+        .long           43
+
+        .section        .xdata$baz,"dr"
+        .linkonce       discard
+        .p2align        3
+        .long           44
+
+        .def            foo;
+        .scl            2;
+        .type           32;
+        .endef
+        .section        .text$foo,"xr",discard,foo
+        .globl          foo
+        .p2align        4
+foo:
+        ret
+
+        .def            bar;
+        .scl            2;
+        .type           32;
+        .endef
+        .section        .text$bar,"xr",discard,bar
+        .globl          bar
+        .p2align        4
+bar:
+        ret

test/ELF/linkerscript/Inputs/at6.s

@@ -0,0 +1,11 @@
+.global _start
+.text
+_start:
+nop
+
+.section .sec1,"aw",@progbits
+.long 1
+
+.section .sec2,"aw",@progbits
+.long 2
+

test/ELF/linkerscript/Inputs/at7.s

@@ -0,0 +1,7 @@
+.global _start
+.text
+_start:
+nop
+
+.section .sec, "aw"
+.word 4

test/ELF/linkerscript/Inputs/at8.s

@@ -0,0 +1,8 @@
+.section .sec1,"aw",@progbits
+.quad   1
+
+.section .sec2,"aw",@progbits
+.quad   2
+
+.section .sec3,"aw",@progbits
+.quad   3

test/ELF/linkerscript/at6.test

@@ -0,0 +1,30 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/at6.s -o %t.o
+# RUN: ld.lld %t.o --script %s -o %t
+# RUN: llvm-readelf -sections -program-headers %t | FileCheck %s
+
+MEMORY {
+  FLASH : ORIGIN = 0x08000000, LENGTH = 0x100
+  RAM   : ORIGIN = 0x20000000, LENGTH = 0x200
+}
+
+SECTIONS {
+ .text : { *(.text) } > FLASH
+ .sec1 : { *(.sec1) } > RAM
+ .sec2 : { *(.sec2) } > RAM AT > FLASH
+}
+
+# Make sure we create a separate PT_LOAD entry for .sec2. Previously,
+# it was added to the PT_LOAD entry of .sec1
+
+# CHECK: Name              Type            Address          Off
+# CHECK: .text             PROGBITS        0000000008000000 001000
+# CHECK: .sec1             PROGBITS        0000000020000000 002000
+# CHECK: .sec2             PROGBITS        0000000020000004 002004
+
+# CHECK: Program Headers:
+# CHECK:      Type  Offset   VirtAddr           PhysAddr
+# CHECK-NEXT: LOAD  0x001000 0x0000000008000000 0x0000000008000000
+# CHECK-NEXT: LOAD  0x002000 0x0000000020000000 0x0000000020000000
+# CHECK-NEXT: LOAD  0x002004 0x0000000020000004 0x0000000008000001
+# CHECK-NOT: LOAD

test/ELF/linkerscript/at7.test

@@ -0,0 +1,28 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/at7.s -o %t.o
+# RUN: ld.lld %t.o --script %s -o %t
+# RUN: llvm-readelf -sections -program-headers %t | FileCheck %s
+
+MEMORY {
+  RAM    : ORIGIN = 0x20000000, LENGTH = 0x200
+}
+
+SECTIONS {
+ .text : { *(.text) } > RAM AT> RAM
+ .sec  : { *(.sec)  } > RAM
+}
+
+# Make sure the memory for the .text section is only reserved once.
+# Previously, the location counter for both MemRegion and LMARegion
+# was increased unconditionally.
+
+
+# CHECK: Name              Type            Address          Off
+# CHECK: .text             PROGBITS        0000000020000000 001000
+# CHECK: .sec             PROGBITS        0000000020000001 001001
+
+# CHECK: Program Headers:
+# CHECK:      Type  Offset   VirtAddr           PhysAddr
+# CHECK-NEXT: LOAD  0x001000 0x0000000020000000 0x0000000020000000
+# CHECK-NEXT: LOAD  0x001001 0x0000000020000001 0x0000000020000001
+# CHECK-NOT: LOAD

test/ELF/linkerscript/at8.test

@@ -0,0 +1,31 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/at8.s -o %t.o
+# RUN: ld.lld %t.o --script %s -o %t
+# RUN: llvm-readelf -sections -program-headers %t | FileCheck %s
+
+MEMORY {
+  FLASH  : ORIGIN = 0x08000000, LENGTH = 0x100
+  RAM    : ORIGIN = 0x20000000, LENGTH = 0x200
+}
+
+SECTIONS {
+ .text : { *(.text) } > FLASH
+ .sec1 : { *(.sec1) } > RAM AT > FLASH
+ .sec2 : { *(.sec2) } > RAM
+ .sec3 : { *(.sec3) } > RAM AT > FLASH
+}
+
+# Make sure we do not issue a load-address overlap error
+# Previously, .sec3 would overwrite the LMAOffset in the
+# PT_LOAD header.
+
+# CHECK: Name              Type            Address          Off
+# CHECK: .text             PROGBITS        0000000008000000 001000
+# CHECK: .sec1             PROGBITS        0000000020000000 001000
+# CHECK: .sec2             PROGBITS        0000000020000008 001008
+# CHECK: .sec3             PROGBITS        0000000020000010 001010
+
+# CHECK: Program Headers:
+# CHECK:      Type  Offset   VirtAddr           PhysAddr
+# CHECK-NEXT: LOAD  0x001000 0x0000000020000000 0x0000000008000000
+# CHECK-NOT: LOAD