From c625b996527335c4fd6b6aa246655a993487e846 Mon Sep 17 00:00:00 2001
From: Lang Hames <lhames@gmail.com>
Date: Tue, 20 Feb 2024 10:07:29 -0800
Subject: [ORC] Add SectCreateMaterializationUnit, llvm-jitlink -sectcreate
 option.

The SectCreateMaterializationUnit creates a LinkGraph with a single named
section containing a single named block whose content is given by a
MemoryBuffer. It is intended to support emulation of ld64's -sectcreate option.
---
 llvm/tools/llvm-jitlink/llvm-jitlink.cpp | 61 ++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

(limited to 'llvm/tools')

diff --git a/llvm/tools/llvm-jitlink/llvm-jitlink.cpp b/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
index 769ed17..f628077 100644
--- a/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
+++ b/llvm/tools/llvm-jitlink/llvm-jitlink.cpp
@@ -30,6 +30,7 @@
 #include "llvm/ExecutionEngine/Orc/MachOPlatform.h"
 #include "llvm/ExecutionEngine/Orc/MapperJITLinkMemoryManager.h"
 #include "llvm/ExecutionEngine/Orc/ObjectFileInterface.h"
+#include "llvm/ExecutionEngine/Orc/SectCreate.h"
 #include "llvm/ExecutionEngine/Orc/Shared/OrcRTBridge.h"
 #include "llvm/ExecutionEngine/Orc/TargetProcess/JITLoaderGDB.h"
 #include "llvm/ExecutionEngine/Orc/TargetProcess/JITLoaderPerf.h"
@@ -162,6 +163,12 @@ static cl::list<std::string>
             cl::desc("Inject symbol aliases (syntax: <alias-name>=<aliasee>)"),
             cl::cat(JITLinkCategory));
 
+static cl::list<std::string>
+    SectCreate("sectcreate",
+               cl::desc("given <sectname>,<filename>[:<sym>=<offset>,...]  "
+                        "add the content of <filename> to <sectname>"),
+               cl::cat(JITLinkCategory));
+
 static cl::list<std::string> TestHarnesses("harness", cl::Positional,
                                            cl::desc("Test harness files"),
                                            cl::PositionalEatsArgs,
@@ -1666,6 +1673,57 @@ static Error addAliases(Session &S,
   return Error::success();
 }
 
+static Error addSectCreates(Session &S,
+                            const std::map<unsigned, JITDylib *> &IdxToJD) {
+  for (auto SCItr = SectCreate.begin(), SCEnd = SectCreate.end();
+       SCItr != SCEnd; ++SCItr) {
+
+    unsigned SCArgIdx = SectCreate.getPosition(SCItr - SectCreate.begin());
+    auto &JD = *std::prev(IdxToJD.lower_bound(SCArgIdx))->second;
+
+    StringRef SCArg(*SCItr);
+
+    auto [SectAndFileName, ExtraSymbolsString] = SCArg.split(':');
+    auto [SectName, FileName] = SectAndFileName.rsplit(',');
+    if (SectName.empty())
+      return make_error<StringError>("In -sectcreate=" + SCArg +
+                                         ", filename component cannot be empty",
+                                     inconvertibleErrorCode());
+    if (FileName.empty())
+      return make_error<StringError>("In -sectcreate=" + SCArg +
+                                         ", filename component cannot be empty",
+                                     inconvertibleErrorCode());
+
+    auto Content = MemoryBuffer::getFile(FileName);
+    if (!Content)
+      return createFileError(FileName, errorCodeToError(Content.getError()));
+
+    SectCreateMaterializationUnit::ExtraSymbolsMap ExtraSymbols;
+    while (!ExtraSymbolsString.empty()) {
+      StringRef NextSymPair;
+      std::tie(NextSymPair, ExtraSymbolsString) = ExtraSymbolsString.split(',');
+
+      auto [Sym, OffsetString] = NextSymPair.split('=');
+      size_t Offset;
+
+      if (OffsetString.getAsInteger(0, Offset))
+        return make_error<StringError>("In -sectcreate=" + SCArg + ", " +
+                                           OffsetString +
+                                           " is not a valid integer",
+                                       inconvertibleErrorCode());
+
+      ExtraSymbols[S.ES.intern(Sym)] = {JITSymbolFlags::Exported, Offset};
+    }
+
+    if (auto Err = JD.define(std::make_unique<SectCreateMaterializationUnit>(
+            S.ObjLayer, SectName.str(), MemProt::Read, 16, std::move(*Content),
+            std::move(ExtraSymbols))))
+      return Err;
+  }
+
+  return Error::success();
+}
+
 static Error addTestHarnesses(Session &S) {
   LLVM_DEBUG(dbgs() << "Adding test harness objects...\n");
   for (auto HarnessFile : TestHarnesses) {
@@ -2016,6 +2074,9 @@ static Error addSessionInputs(Session &S) {
   if (auto Err = addAliases(S, IdxToJD))
     return Err;
 
+  if (auto Err = addSectCreates(S, IdxToJD))
+    return Err;
+
   if (!TestHarnesses.empty())
     if (auto Err = addTestHarnesses(S))
       return Err;
-- 
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