[MCJIT] Add command-line argument to llvm-rtdyld to specify target addresses for

sections.

This allows fine-grained control of the memory layout of hypothetical target
processes for testing purposes.

llvm-svn: 217122

1 files changed, 102 insertions, 12 deletions

diff --git a/llvm/tools/llvm-rtdyld/llvm-rtdyld.cpp b/llvm/tools/llvm-rtdyld/llvm-rtdyld.cpp
index e8e2e89f9ac..87d381e994f 100644
--- a/llvm/tools/llvm-rtdyld/llvm-rtdyld.cpp
+++ b/llvm/tools/llvm-rtdyld/llvm-rtdyld.cpp
@@ -34,6 +34,7 @@
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
+#include <list>
 #include <system_error>
 
 using namespace llvm;
@@ -98,6 +99,11 @@ TargetSectionSep("target-section-sep",
                  cl::init(0),
                  cl::Hidden);
 
+static cl::list<std::string>
+SpecificSectionMappings("map-section",
+                        cl::desc("Map a section to a specific address."),
+                        cl::ZeroOrMore);
+
 /* *** */
 
 // A trivial memory manager that doesn't do anything fancy, just uses the
@@ -320,6 +326,53 @@ static int checkAllExpressions(RuntimeDyldChecker &Checker) {
   return 0;
 }
 
+std::map<void*, uint64_t>
+applySpecificSectionMappings(RuntimeDyldChecker &Checker) {
+
+  std::map<void*, uint64_t> SpecificMappings;
+
+  for (StringRef Mapping : SpecificSectionMappings) {
+
+    size_t EqualsIdx = Mapping.find_first_of("=");
+    StringRef SectionIDStr = Mapping.substr(0, EqualsIdx);
+    size_t ComaIdx = Mapping.find_first_of(",");
+
+    if (ComaIdx == StringRef::npos) {
+      errs() << "Invalid section specification '" << Mapping
+             << "'. Should be '<file name>,<section name>=<addr>'\n";
+      exit(1);
+    }
+
+    StringRef FileName = SectionIDStr.substr(0, ComaIdx);
+    StringRef SectionName = SectionIDStr.substr(ComaIdx + 1);
+
+    uint64_t OldAddrInt;
+    std::string ErrorMsg;
+    std::tie(OldAddrInt, ErrorMsg) =
+      Checker.getSectionAddr(FileName, SectionName, true);
+
+    if (ErrorMsg != "") {
+      errs() << ErrorMsg;
+      exit(1);
+    }
+
+    void* OldAddr = reinterpret_cast<void*>(static_cast<uintptr_t>(OldAddrInt));
+
+    StringRef NewAddrStr = Mapping.substr(EqualsIdx + 1);
+    uint64_t NewAddr;
+
+    if (NewAddrStr.getAsInteger(0, NewAddr)) {
+      errs() << "Invalid section address in mapping: " << Mapping << "\n";
+      exit(1);
+    }
+
+    Checker.getRTDyld().mapSectionAddress(OldAddr, NewAddr);
+    SpecificMappings[OldAddr] = NewAddr;
+  }
+
+  return SpecificMappings;
+}
+
 // Scatter sections in all directions!
 // Remaps section addresses for -verify mode. The following command line options
 // can be used to customize the layout of the memory within the phony target's
@@ -333,7 +386,40 @@ static int checkAllExpressions(RuntimeDyldChecker &Checker) {
 //
 void remapSections(const llvm::Triple &TargetTriple,
                    const TrivialMemoryManager &MemMgr,
-                   RuntimeDyld &RTDyld) {
+                   RuntimeDyldChecker &Checker) {
+
+  // Set up a work list (section addr/size pairs).
+  typedef std::list<std::pair<void*, uint64_t>> WorklistT;
+  WorklistT Worklist;
+
+  for (const auto& CodeSection : MemMgr.FunctionMemory)
+    Worklist.push_back(std::make_pair(CodeSection.base(), CodeSection.size()));
+  for (const auto& DataSection : MemMgr.DataMemory)
+    Worklist.push_back(std::make_pair(DataSection.base(), DataSection.size()));
+
+  // Apply any section-specific mappings that were requested on the command
+  // line.
+  typedef std::map<void*, uint64_t> AppliedMappingsT;
+  AppliedMappingsT AppliedMappings = applySpecificSectionMappings(Checker);
+
+  // Keep an "already allocated" mapping of section target addresses to sizes.
+  // Sections whose address mappings aren't specified on the command line will
+  // allocated around the explicitly mapped sections while maintaining the
+  // minimum separation.
+  std::map<uint64_t, uint64_t> AlreadyAllocated;
+
+  // Move the previously applied mappings into the already-allocated map.
+  for (WorklistT::iterator I = Worklist.begin(), E = Worklist.end();
+       I != E;) {
+    WorklistT::iterator Tmp = I;
+    ++I;
+    AppliedMappingsT::iterator AI = AppliedMappings.find(Tmp->first);
+
+    if (AI != AppliedMappings.end()) {
+      AlreadyAllocated[AI->second] = Tmp->second;
+      Worklist.erase(Tmp);
+    }
+  }
 
   // If the -target-addr-end option wasn't explicitly passed, then set it to a
   // sensible default based on the target triple.
@@ -346,19 +432,23 @@ void remapSections(const llvm::Triple &TargetTriple,
     // there's nothing to do in the 64-bit case.
   }
 
-  uint64_t NextSectionAddress = TargetAddrStart;
+  // Process any elements remaining in the worklist.
+  while (!Worklist.empty()) {
+    std::pair<void*, uint64_t> CurEntry = Worklist.front();
+    Worklist.pop_front();
 
-  // Remap code sections.
-  for (const auto& CodeSection : MemMgr.FunctionMemory) {
-    RTDyld.mapSectionAddress(CodeSection.base(), NextSectionAddress);
-    NextSectionAddress += CodeSection.size() + TargetSectionSep;
-  }
+    uint64_t NextSectionAddr = TargetAddrStart;
+
+    for (const auto &Alloc : AlreadyAllocated)
+      if (NextSectionAddr + CurEntry.second + TargetSectionSep <= Alloc.first)
+        break;
+      else
+        NextSectionAddr = Alloc.first + Alloc.second + TargetSectionSep;
 
-  // Remap data sections.
-  for (const auto& DataSection : MemMgr.DataMemory) {
-    RTDyld.mapSectionAddress(DataSection.base(), NextSectionAddress);
-    NextSectionAddress += DataSection.size() + TargetSectionSep;
+    AlreadyAllocated[NextSectionAddr] = CurEntry.second;
+    Checker.getRTDyld().mapSectionAddress(CurEntry.first, NextSectionAddr);
   }
+
 }
 
 // Load and link the objects specified on the command line, but do not execute
@@ -435,7 +525,7 @@ static int linkAndVerify() {
   }
 
   // Re-map the section addresses into the phony target address space.
-  remapSections(TheTriple, MemMgr, Dyld);
+  remapSections(TheTriple, MemMgr, Checker);
 
   // Resolve all the relocations we can.
   Dyld.resolveRelocations();