test: add tests and docs for section address linker options

docs/userguide/documentation/layout.rst

@@ -277,6 +277,28 @@ alignment specified in :code:`ALIGN`.
 There are various linker command-line options for setting output section
 VMA: ``-Tbss``, ``-Tdata``, ``-Ttext`` and ``--section-start``.
 
+--section-start=sectionname=org
+    Assigns the absolute address org to the named output section.
+    You may use this option multiple times to place multiple sections at specific addresses.
+
+-Ttext=org
+    Same as ``--section-start`` with ``.text`` as the section name.
+
+-Tdata=org
+    Same as ``--section-start`` with ``.data`` as the section name.
+
+-Tbss=org
+    Same as ``--section-start`` with ``.bss`` as the section name.
+
+-Ttext-segment=org
+    When creating an ELF executable, it sets the address of the first byte of the text segment.
+
+-Trodata-segment=org
+    When creating an ELF executable or shared object for a target where the read-only data is in its own segment separate from the executable text, it sets the address of the first byte of the read-only data segment.
+
+-Tldata-segment=org
+    When creating an ELF executable or shared object for the x86-64 medium memory model, it sets the address of the first byte of the ldata segment.
+
 When both the linker script and the command line specify an output-section address,
 the command-line option takes precedence and overrides the script's explicit address.
 

include/eld/Config/GeneralOptions.h

@@ -746,6 +746,13 @@ class GeneralOptions {
   const std::optional<uint64_t> &imageBase() const { return ImageBase; }
 
   void setImageBase(uint64_t Value) { ImageBase = Value; }
+
+  const std::optional<uint64_t> &textSegment() const { return TextSegment; }
+  void setTextSegment(uint64_t Value) { TextSegment = Value; }
+  const std::optional<uint64_t> &rodataSegment() const { return RodataSegment; }
+  void setRodataSegment(uint64_t Value) { RodataSegment = Value; }
+  const std::optional<uint64_t> &ldataSegment() const { return LdataSegment; }
+  void setLdataSegment(uint64_t Value) { LdataSegment = Value; }
 
   /// entry point
   const std::string &entry() const;
@@ -1377,6 +1384,9 @@ class GeneralOptions {
   std::vector<std::string> LTOOutputFile;
   bool BCompactDyn = false;          // z,compactdyn
   std::optional<uint64_t> ImageBase; // --image-base=value
+  std::optional<uint64_t> TextSegment;
+  std::optional<uint64_t> RodataSegment;
+  std::optional<uint64_t> LdataSegment;
   std::string Entry;
   SymbolRenameMap SymbolRenames;
   AddressMapType AddressMap;

include/eld/Driver/GnuLinkerOptions.td

@@ -225,6 +225,16 @@ defm Ttext_segment
                     "Specify an address for the .text-segment segment">,
       MetaVarName<"<address>">,
       Group<grp_scriptopts>;
+defm Trodata_segment
+    : dashEqWithOpt<"Trodata-segment", "Trodata-segment", "Trodata_segment",
+                    "Specify an address for the .rodata-segment segment">,
+      MetaVarName<"<address>">,
+      Group<grp_scriptopts>;
+defm Tldata_segment
+    : dashEqWithOpt<"Tldata-segment", "Tldata-segment", "Tldata_segment",
+                    "Specify an address for the .ldata-segment segment">,
+      MetaVarName<"<address>">,
+      Group<grp_scriptopts>;
 defm Tdata
     : smDash<"Tdata", "Tdata", "Specify an address for the .data section">,
       MetaVarName<"<address>">,

lib/LinkerWrapper/GnuLdDriver.cpp

@@ -858,6 +858,27 @@ bool GnuLdDriver::processOptions(llvm::opt::InputArgList &Args) {
     Config.options().addressMap().insert(std::make_pair(".text", addr));
   }
 
+  // -Ttext-segment=value
+  if (llvm::opt::Arg *arg = Args.getLastArg(T::Ttext_segment)) {
+    uint64_t addr = 0;
+    if (!llvm::StringRef(arg->getValue()).getAsInteger(0, addr))
+      Config.options().setTextSegment(addr);
+  }
+
+  // -Trodata-segment=value
+  if (llvm::opt::Arg *arg = Args.getLastArg(T::Trodata_segment)) {
+    uint64_t addr = 0;
+    if (!llvm::StringRef(arg->getValue()).getAsInteger(0, addr))
+      Config.options().setRodataSegment(addr);
+  }
+
+  // -Tldata-segment=value
+  if (llvm::opt::Arg *arg = Args.getLastArg(T::Tldata_segment)) {
+    uint64_t addr = 0;
+    if (!llvm::StringRef(arg->getValue()).getAsInteger(0, addr))
+      Config.options().setLdataSegment(addr);
+  }
+
   // --dynamic-list
   for (auto *Arg : Args.filtered(T::dynamic_list))
     Config.options().getDynList().emplace(Arg->getValue());

lib/Target/GNULDBackend.cpp

@@ -4060,6 +4060,8 @@ bool GNULDBackend::symbolNeedsCopyReloc(const Relocation &pReloc,
 }
 
 uint64_t GNULDBackend::getImageBase(bool HasInterp, bool LoadEHdr) const {
+  if (auto TextSegment = config().options().textSegment())
+    return *TextSegment;
   if (auto ImageBase = config().options().imageBase())
     return *ImageBase;
   return m_pInfo->startAddr(

test/Common/standalone/CommandLine/Ttext/Inputs/1.c

@@ -0,0 +1,3 @@
+int data_var = 1;
+int bss_var;
+int foo() { return 0; }

test/Common/standalone/CommandLine/Ttext/Inputs/force-sections.t

@@ -0,0 +1,5 @@
+SECTIONS {
+  .text : { *(.text*) }
+  .data : { *(.data*) *(.sdata*) }
+  .bss  : { *(.bss*)  *(.sbss*)  }
+}

test/Common/standalone/CommandLine/Ttext/Ttext.test

@@ -0,0 +1,16 @@
+#---Ttext.test--------------------------- Executable,LS -----------------#
+#BEGIN_COMMENT
+# This checks for options -Ttext, -Tdata and -Tbss that are handled in the linker.
+#END_COMMENT
+#START_TEST
+RUN: %clang %clangopts -c %p/Inputs/1.c -o %t1.o
+RUN: %link %linkopts %t1.o -o %t1.out -Ttext=0x10000000
+RUN: %readelf -S %t1.out -W | %filecheck %s --check-prefix=CHECK-TEXT
+CHECK-TEXT: .text {{.*}} {{0*}}10000000
+RUN: %link %linkopts %t1.o -T %p/Inputs/force-sections.t -o %t2.out -Tdata=0x20000000
+RUN: %readelf -S %t2.out -W | %filecheck %s --check-prefix=CHECK-DATA
+CHECK-DATA: .data {{.*}} {{0*}}20000000
+RUN: %link %linkopts %t1.o -T %p/Inputs/force-sections.t -o %t3.out -Tbss=0x30000000
+RUN: %readelf -S %t3.out -W | %filecheck %s --check-prefix=CHECK-BSS
+CHECK-BSS: .bss {{.*}} {{0*}}30000000
+#END_TEST

test/Common/standalone/CommandLine/TtextSegment/Inputs/1.c

@@ -0,0 +1 @@
+int foo() { return 0; }

test/Common/standalone/CommandLine/TtextSegment/TtextSegment.test

@@ -0,0 +1,10 @@
+#---TtextSegment.test--------------------------- Executable,LS -----------------#
+#BEGIN_COMMENT
+# This checks for option -Ttext-segment that is handled in the linker.
+#END_COMMENT
+#START_TEST
+RUN: %clang %clangopts -c %p/Inputs/1.c -o %t1.o
+RUN: %link %linkopts %t1.o -o %t1.out -Ttext-segment=0x10000000
+RUN: %readelf -l %t1.out -W | %filecheck %s --check-prefix=CHECK-TEXT-SEGMENT
+CHECK-TEXT-SEGMENT: LOAD {{.*}} 0x{{0*}}10000000
+#END_TEST

test/Hexagon/standalone/CommandLine/SectionStart/SectionStart.test

@@ -0,0 +1,10 @@
+#---SectionStart.test--------------------------- Executable,LS -----------------#
+#BEGIN_COMMENT
+# This checks for option --section-start that is being handled in the linker.
+#END_COMMENT
+#START_TEST
+RUN: %clang %clangopts -c %p/Inputs/1.c -o %t1.1.o
+RUN: %link %linkopts %t1.1.o -o %t2.out --section-start .text=0xF0000000
+RUN: %readelf -s %t2.out -W | %filecheck %s
+#CHECK: f0000000
+#END_TEST

test/x86_64/standalone/CommandLine/TldataSegment/Inputs/1.c

@@ -0,0 +1,2 @@
+int data_var = 1;
+int foo() { return 0; }

test/x86_64/standalone/CommandLine/TldataSegment/TldataSegment.test

@@ -0,0 +1,10 @@
+#---TldataSegment.test--------------------------- Executable,LS -----------------#
+#BEGIN_COMMENT
+# This checks for option -Tldata-segment that is handled in the linker.
+#END_COMMENT
+#START_TEST
+RUN: %clang %clangopts -c %p/Inputs/1.c -o %t1.o
+RUN: %link %linkopts %t1.o -o %t1.out -Tldata-segment=0x30000000
+RUN: %readelf -l %t1.out -W | %filecheck %s --check-prefix=CHECK-LDATA-SEGMENT
+CHECK-LDATA-SEGMENT: LOAD {{.*}} 0x{{0*}}30000000
+#END_TEST

test/x86_64/standalone/CommandLine/TrodataSegment/Inputs/1.c

@@ -0,0 +1,2 @@
+const int rodata_var = 1;
+int foo() { return 0; }

test/x86_64/standalone/CommandLine/TrodataSegment/TrodataSegment.test

@@ -0,0 +1,10 @@
+#---TrodataSegment.test--------------------------- Executable,LS -----------------#
+#BEGIN_COMMENT
+# This checks for option -Trodata-segment that is handled in the linker.
+#END_COMMENT
+#START_TEST
+RUN: %clang %clangopts -c %p/Inputs/1.c -o %t1.o
+RUN: %link %linkopts %t1.o -o %t1.out -Trodata-segment=0x20000000
+RUN: %readelf -l %t1.out -W | %filecheck %s --check-prefix=CHECK-RODATA-SEGMENT
+CHECK-RODATA-SEGMENT: LOAD {{.*}} 0x{{0*}}20000000
+#END_TEST