LTO: Hash the parts of the LTO configuration that affect code generation.

Most importantly, we need to hash the relocation model, otherwise we can
end up trying to link non-PIC object files into PIEs or DSOs.

Differential Revision: https://reviews.llvm.org/D27556

llvm-svn: 289024

llvm/include/llvm/CodeGen/CommandFlags.h

@@ -232,6 +232,11 @@ UseCtors("use-ctors",
              cl::desc("Use .ctors instead of .init_array."),
              cl::init(false));
 
+cl::opt<bool> RelaxELFRelocations(
+    "relax-elf-relocations",
+    cl::desc("Emit GOTPCRELX/REX_GOTPCRELX instead of GOTPCREL on x86-64 ELF"),
+    cl::init(false));
+
 cl::opt<bool> DataSections("data-sections",
                            cl::desc("Emit data into separate sections"),
                            cl::init(false));
@@ -288,6 +293,7 @@ static inline TargetOptions InitTargetOptionsFromCodeGenFlags() {
   Options.StackAlignmentOverride = OverrideStackAlignment;
   Options.StackSymbolOrdering = StackSymbolOrdering;
   Options.UseInitArray = !UseCtors;
+  Options.RelaxELFRelocations = RelaxELFRelocations;
   Options.DataSections = DataSections;
   Options.FunctionSections = FunctionSections;
   Options.UniqueSectionNames = UniqueSectionNames;

llvm/include/llvm/LTO/Config.h

@@ -33,6 +33,8 @@ namespace lto {
 /// LTO configuration. A linker can configure LTO by setting fields in this data
 /// structure and passing it to the lto::LTO constructor.
 struct Config {
+  // Note: when adding fields here, consider whether they need to be added to
+  // computeCacheKey in LTO.cpp.
   std::string CPU;
   TargetOptions Options;
   std::vector<std::string> MAttrs;

llvm/lib/LTO/LTO.cpp

@@ -50,8 +50,8 @@ using namespace object;
 // export/import and other global analysis results.
 // The hash is produced in \p Key.
 static void computeCacheKey(
-    SmallString<40> &Key, const ModuleSummaryIndex &Index, StringRef ModuleID,
-    const FunctionImporter::ImportMapTy &ImportList,
+    SmallString<40> &Key, const Config &Conf, const ModuleSummaryIndex &Index,
+    StringRef ModuleID, const FunctionImporter::ImportMapTy &ImportList,
     const FunctionImporter::ExportSetTy &ExportList,
     const std::map<GlobalValue::GUID, GlobalValue::LinkageTypes> &ResolvedODR,
     const GVSummaryMapTy &DefinedGlobals) {
@@ -67,6 +67,39 @@ static void computeCacheKey(
   Hasher.update(LLVM_REVISION);
 #endif
 
+  // Include the parts of the LTO configuration that affect code generation.
+  auto AddString = [&](StringRef Str) {
+    Hasher.update(Str);
+    Hasher.update(ArrayRef<uint8_t>{0});
+  };
+  auto AddUnsigned = [&](unsigned I) {
+    uint8_t Data[4];
+    Data[0] = I;
+    Data[1] = I >> 8;
+    Data[2] = I >> 16;
+    Data[3] = I >> 24;
+    Hasher.update(ArrayRef<uint8_t>{Data, 4});
+  };
+  AddString(Conf.CPU);
+  // FIXME: Hash more of Options. For now all clients initialize Options from
+  // command-line flags (which is unsupported in production), but may set
+  // RelaxELFRelocations. The clang driver can also pass FunctionSections,
+  // DataSections and DebuggerTuning via command line flags.
+  AddUnsigned(Conf.Options.RelaxELFRelocations);
+  AddUnsigned(Conf.Options.FunctionSections);
+  AddUnsigned(Conf.Options.DataSections);
+  AddUnsigned((unsigned)Conf.Options.DebuggerTuning);
+  for (auto &A : Conf.MAttrs)
+    AddString(A);
+  AddUnsigned(Conf.RelocModel);
+  AddUnsigned(Conf.CodeModel);
+  AddUnsigned(Conf.CGOptLevel);
+  AddUnsigned(Conf.OptLevel);
+  AddString(Conf.OptPipeline);
+  AddString(Conf.AAPipeline);
+  AddString(Conf.OverrideTriple);
+  AddString(Conf.DefaultTriple);
+
   // Include the hash for the current module
   auto ModHash = Index.getModuleHash(ModuleID);
   Hasher.update(ArrayRef<uint8_t>((uint8_t *)&ModHash[0], sizeof(ModHash)));
@@ -562,7 +595,7 @@ public:
 
     SmallString<40> Key;
     // The module may be cached, this helps handling it.
-    computeCacheKey(Key, CombinedIndex, ModuleID, ImportList, ExportList,
+    computeCacheKey(Key, Conf, CombinedIndex, ModuleID, ImportList, ExportList,
                     ResolvedODR, DefinedGlobals);
     if (AddStreamFn CacheAddStream = Cache(Task, Key))
       return RunThinBackend(CacheAddStream);

llvm/test/ThinLTO/X86/cache-config.ll

@@ -0,0 +1,27 @@
+; RUN: rm -rf %t.cache && mkdir %t.cache
+; RUN: opt -module-hash -module-summary %s -o %t.bc
+
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -mcpu=yonah
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -relax-elf-relocations
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -function-sections
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -data-sections
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -debugger-tune=sce
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -mattr=+sse2
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -relocation-model=static
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -code-model=large
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -cg-opt-level=0
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -O1
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -opt-pipeline=loweratomic
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -aa-pipeline=basic-aa
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -override-triple=x86_64-unknown-linux-gnu
+; RUN: llvm-lto2 -o %t.o %t.bc -cache-dir %t.cache -r=%t.bc,globalfunc,plx -default-triple=x86_64-unknown-linux-gnu
+; RUN: ls %t.cache | count 15
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @globalfunc() {
+entry:
+  ret void
+}

llvm/tools/llvm-lto2/llvm-lto2.cpp

@@ -17,6 +17,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/LTO/Caching.h"
+#include "llvm/CodeGen/CommandFlags.h"
 #include "llvm/LTO/LTO.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/TargetSelect.h"
@@ -31,6 +32,11 @@ static cl::opt<char>
                            "(default = '-O2')"),
              cl::Prefix, cl::ZeroOrMore, cl::init('2'));
 
+static cl::opt<char> CGOptLevel(
+    "cg-opt-level",
+    cl::desc("Codegen optimization level (0, 1, 2 or 3, default = '2')"),
+    cl::init('2'));
+
 static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore,
                                             cl::desc("<input bitcode files>"));
 
@@ -74,6 +80,15 @@ static cl::list<std::string> SymbolResolutions(
              "A resolution for each symbol must be specified."),
     cl::ZeroOrMore);
 
+static cl::opt<std::string> OverrideTriple(
+    "override-triple",
+    cl::desc("Replace target triples in input files with this triple"));
+
+static cl::opt<std::string> DefaultTriple(
+    "default-triple",
+    cl::desc(
+        "Replace unspecified target triples in input files with this triple"));
+
 static void check(Error E, std::string Msg) {
   if (!E)
     return;
@@ -146,6 +161,13 @@ int main(int argc, char **argv) {
     exit(1);
   };
 
+  Conf.CPU = MCPU;
+  Conf.Options = InitTargetOptionsFromCodeGenFlags();
+  Conf.MAttrs = MAttrs;
+  if (auto RM = getRelocModel())
+    Conf.RelocModel = *RM;
+  Conf.CodeModel = CMModel;
+
   if (SaveTemps)
     check(Conf.addSaveTemps(OutputFilename + "."),
           "Config::addSaveTemps failed");
@@ -155,6 +177,26 @@ int main(int argc, char **argv) {
   Conf.AAPipeline = AAPipeline;
 
   Conf.OptLevel = OptLevel - '0';
+  switch (CGOptLevel) {
+  case '0':
+    Conf.CGOptLevel = CodeGenOpt::None;
+    break;
+  case '1':
+    Conf.CGOptLevel = CodeGenOpt::Less;
+    break;
+  case '2':
+    Conf.CGOptLevel = CodeGenOpt::Default;
+    break;
+  case '3':
+    Conf.CGOptLevel = CodeGenOpt::Aggressive;
+    break;
+  default:
+    llvm::errs() << "invalid cg optimization level: " << CGOptLevel << '\n';
+    return 1;
+  }
+
+  Conf.OverrideTriple = OverrideTriple;
+  Conf.DefaultTriple = DefaultTriple;
 
   ThinBackend Backend;
   if (ThinLTODistributedIndexes)