steven_wu created this revision.
steven_wu added a subscriber: cfe-commits.
steven_wu added a dependency: D17390: Introduce -fembed-bitcode driver option.
Teach clang to embed bitcode inside bitcode. When -fembed-bitcode cc1
option is used, clang will embed both the input bitcode and cc1
commandline into the bitcode in special sections before compiling to
the object file. Using -fembed-bitcode-marker will only introduce a
marker in both sections.
Depends on D17390
http://reviews.llvm.org/D17392
Files:
include/clang/CodeGen/BackendUtil.h
include/clang/Frontend/CodeGenOptions.def
include/clang/Frontend/CodeGenOptions.h
lib/CodeGen/BackendUtil.cpp
lib/CodeGen/CodeGenAction.cpp
lib/Driver/Tools.cpp
lib/Frontend/CompilerInvocation.cpp
test/Frontend/embed-bitcode.ll
Index: test/Frontend/embed-bitcode.ll
===================================================================
--- /dev/null
+++ test/Frontend/embed-bitcode.ll
@@ -0,0 +1,48 @@
+; check .ll input
+; RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -emit-llvm \
+; RUN: -fembed-bitcode -x ir %s -o - \
+; RUN: | FileCheck %s
+; RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -emit-llvm \
+; RUN: -fembed-bitcode-marker -x ir %s -o - \
+; RUN: | FileCheck %s -check-prefix=CHECK-MARKER
+; RUN: %clang_cc1 -triple aarch64-unknown-linux-gnueabi -emit-llvm \
+; RUN: -fembed-bitcode -x ir %s -o - \
+; RUN: | FileCheck %s -check-prefix=CHECK-ELF
+
+; check .bc input
+; RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -emit-llvm-bc \
+; RUN: -x ir %s -o %t.bc
+; RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -emit-llvm \
+; RUN: -fembed-bitcode -x ir %t.bc -o - \
+; RUN: | FileCheck %s
+; RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -emit-llvm \
+; RUN: -fembed-bitcode-marker -x ir %t.bc -o - \
+; RUN: | FileCheck %s -check-prefix=CHECK-MARKER
+
+; run through -fembed-bitcode twice and make sure it doesn't crash
+; RUN: %clang_cc1 -triple thumbv7-apple-ios8.0.0 -emit-llvm-bc \
+; RUN: -fembed-bitcode -x ir %s -o - \
+; RUN: | %clang_cc1 -triple thumbv7-apple-ios8.0.0 -emit-llvm \
+; RUN: -fembed-bitcode -x ir - -o /dev/null
+
+; check the magic number of bitcode at the beginning of the string
+; CHECK: @llvm.embedded.module
+; CHECK: c"\DE\C0\17\0B
+; CHECK: section "__LLVM,__bitcode"
+; CHECK: @llvm.cmdline
+; CHECK: section "__LLVM,__cmdline"
+
+; CHECK-ELF: @llvm.embedded.module
+; CHECK-ELF: section ".llvmbc"
+; CHECK-ELF: @llvm.cmdline
+; CHECK-ELF: section ".llvmcmd"
+
+; CHECK-MARKER: @llvm.embedded.module
+; CHECK-MARKER: constant [0 x i8] zeroinitializer
+; CHECK-MARKER: section "__LLVM,__bitcode"
+; CHECK-MARKER: @llvm.cmdline
+; CHECK-MARKER: section "__LLVM,__cmdline"
+
+define i32 @f0() {
+ ret i32 0
+}
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -616,6 +616,34 @@
}
}
}
+ // Handle -fembed-bitcode option.
+ Opts.EmbedBitcode = Args.hasArg(OPT_fembed_bitcode);
+ Opts.EmbedMarkerOnly = Args.hasArg(OPT_fembed_bitcode_marker);
+ // FIXME: For backend options that are not yet recorded as function
+ // attributes in the IR, keep track of them so we can embed them in a
+ // separate data section and use them when building the bitcode.
+ if (Opts.EmbedBitcode) {
+ for (ArgList::const_iterator A = Args.begin(), AE = Args.end();
+ A != AE; ++ A) {
+ // Do not encode output and input.
+ if ((*A)->getOption().getID() == options::OPT_o ||
+ (*A)->getOption().getID() == options::OPT_INPUT ||
+ (*A)->getOption().getID() == options::OPT_x ||
+ (*A)->getOption().getID() == options::OPT_fembed_bitcode ||
+ ((*A)->getOption().getGroup().isValid() &&
+ (*A)->getOption().getGroup().getID() == options::OPT_W_Group))
+ continue;
+ ArgStringList ASL;
+ (*A)->render(Args, ASL);
+ for (ArgStringList::iterator it = ASL.begin(), ie = ASL.end();
+ it != ie; ++ it) {
+ StringRef ArgStr(*it);
+ Opts.CmdArgs.insert(Opts.CmdArgs.end(), ArgStr.begin(), ArgStr.end());
+ // using \00 to seperate each commandline options.
+ Opts.CmdArgs.push_back('\0');
+ }
+ }
+ }
Opts.InstrumentFunctions = Args.hasArg(OPT_finstrument_functions);
Opts.InstrumentForProfiling = Args.hasArg(OPT_pg);
Index: lib/Driver/Tools.cpp
===================================================================
--- lib/Driver/Tools.cpp
+++ lib/Driver/Tools.cpp
@@ -5553,7 +5553,10 @@
// With -save-temps, we want to save the unoptimized bitcode output from the
// CompileJobAction, use -disable-llvm-passes to get pristine IR generated
// by the frontend.
- if (C.getDriver().isSaveTempsEnabled() && isa<CompileJobAction>(JA))
+ // When -fembed-bitcode is enabled, optimized bitcode is emitted because it
+ // has slightly different breakdown between stages.
+ if (C.getDriver().isSaveTempsEnabled() &&
+ !C.getDriver().embedBitcodeEnabled() && isa<CompileJobAction>(JA))
CmdArgs.push_back("-disable-llvm-passes");
if (Output.getType() == types::TY_Dependencies) {
Index: lib/CodeGen/CodeGenAction.cpp
===================================================================
--- lib/CodeGen/CodeGenAction.cpp
+++ lib/CodeGen/CodeGenAction.cpp
@@ -173,6 +173,8 @@
return;
}
+ EmbedBitcode(TheModule.get(), CodeGenOpts, llvm::MemoryBufferRef());
+
EmitBackendOutput(Diags, CodeGenOpts, TargetOpts, LangOpts,
C.getTargetInfo().getDataLayoutString(),
getModule(), Action, AsmOutStream);
@@ -823,6 +825,9 @@
TheModule->setTargetTriple(TargetOpts.Triple);
}
+ EmbedBitcode(TheModule.get(), CI.getCodeGenOpts(),
+ MainFile->getMemBufferRef());
+
LLVMContext &Ctx = TheModule->getContext();
Ctx.setInlineAsmDiagnosticHandler(BitcodeInlineAsmDiagHandler);
EmitBackendOutput(CI.getDiagnostics(), CI.getCodeGenOpts(), TargetOpts,
Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -16,9 +16,11 @@
#include "clang/Frontend/Utils.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Bitcode/BitcodeWriterPass.h"
+#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/CodeGen/RegAllocRegistry.h"
#include "llvm/CodeGen/SchedulerRegistry.h"
#include "llvm/IR/DataLayout.h"
@@ -721,3 +723,86 @@
}
}
}
+
+static const char* getSectionNameForBitcode(const Triple &T) {
+ switch (T.getObjectFormat()) {
+ case Triple::MachO:
+ return "__LLVM,__bitcode";
+ case Triple::COFF:
+ case Triple::ELF:
+ case Triple::UnknownObjectFormat:
+ return ".llvmbc";
+ }
+}
+
+static const char* getSectionNameForCommandline(const Triple &T) {
+ switch (T.getObjectFormat()) {
+ case Triple::MachO:
+ return "__LLVM,__cmdline";
+ case Triple::COFF:
+ case Triple::ELF:
+ case Triple::UnknownObjectFormat:
+ return ".llvmcmd";
+ }
+}
+
+// With -fembed-bitcode, save a copy of the llvm IR as data in the
+// __LLVM,__bitcode section.
+void clang::EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
+ llvm::MemoryBufferRef Buf)
+{
+ if (!CGOpts.EmbedBitcode && !CGOpts.EmbedMarkerOnly)
+ return;
+
+ // Embed the bitcode for the llvm module.
+ std::string Data;
+ ArrayRef<uint8_t> ModuleData;
+ Triple T(M->getTargetTriple());
+ if (!CGOpts.EmbedMarkerOnly) {
+ if (!isBitcode((const unsigned char*)Buf.getBufferStart(),
+ (const unsigned char*)Buf.getBufferEnd())) {
+ // If the input is LLVM Assembly, bitcode is produced by serializing
+ // the module. Use-lists order need to be perserved in this case.
+ llvm::raw_string_ostream OS(Data);
+ llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
+ ModuleData = ArrayRef<uint8_t>((uint8_t*)OS.str().data(),
+ OS.str().size());
+ } else {
+ // If the input is LLVM bitcode, write the input byte stream directly.
+ ModuleData = ArrayRef<uint8_t>((uint8_t*)Buf.getBufferStart(),
+ Buf.getBufferSize());
+ }
+ }
+ llvm::Constant *ModuleConstant =
+ llvm::ConstantDataArray::get(M->getContext(), ModuleData);
+ // Use Appending linkage so it doesn't get optimized out.
+ llvm::GlobalVariable *GV = new llvm::GlobalVariable(
+ *M, ModuleConstant->getType(), true, llvm::GlobalValue::AppendingLinkage,
+ ModuleConstant);
+ GV->setSection(getSectionNameForBitcode(T));
+ if (llvm::GlobalVariable *Old =
+ M->getGlobalVariable("llvm.embedded.module")) {
+ assert(Old->use_empty() && "llvm.embedded.module must have no uses");
+ GV->takeName(Old);
+ Old->eraseFromParent();
+ } else {
+ GV->setName("llvm.embedded.module");
+ }
+
+ // Embed command-line options.
+ ArrayRef<uint8_t> CmdData((uint8_t*)CGOpts.CmdArgs.data(),
+ CGOpts.CmdArgs.size());
+ llvm::Constant *CmdConstant =
+ llvm::ConstantDataArray::get(M->getContext(), CmdData);
+ GV = new llvm::GlobalVariable(*M, CmdConstant->getType(), true,
+ llvm::GlobalValue::AppendingLinkage,
+ CmdConstant);
+ GV->setSection(getSectionNameForCommandline(T));
+ if (llvm::GlobalVariable *Old = M->getGlobalVariable("llvm.cmdline")) {
+ assert(Old->use_empty() && "llvm.cmdline must have no uses");
+ GV->takeName(Old);
+ Old->eraseFromParent();
+ } else {
+ GV->setName("llvm.cmdline");
+ }
+}
Index: include/clang/Frontend/CodeGenOptions.h
===================================================================
--- include/clang/Frontend/CodeGenOptions.h
+++ include/clang/Frontend/CodeGenOptions.h
@@ -198,6 +198,9 @@
/// Set of sanitizer checks that trap rather than diagnose.
SanitizerSet SanitizeTrap;
+ /// List of backend command-line options for -fembed-bitcode.
+ std::vector<uint8_t> CmdArgs;
+
/// \brief A list of all -fno-builtin-* function names (e.g., memset).
std::vector<std::string> NoBuiltinFuncs;
Index: include/clang/Frontend/CodeGenOptions.def
===================================================================
--- include/clang/Frontend/CodeGenOptions.def
+++ include/clang/Frontend/CodeGenOptions.def
@@ -53,6 +53,8 @@
///< frontend.
CODEGENOPT(DisableRedZone , 1, 0) ///< Set when -mno-red-zone is enabled.
CODEGENOPT(DisableTailCalls , 1, 0) ///< Do not emit tail calls.
+CODEGENOPT(EmbedBitcode , 1, 0) ///< Embed LLVM IR bitcode as data.
+CODEGENOPT(EmbedMarkerOnly , 1, 0) ///< Only create bitcode section as marker
CODEGENOPT(EmitDeclMetadata , 1, 0) ///< Emit special metadata indicating what
///< Decl* various IR entities came from.
///< Only useful when running CodeGen as a
Index: include/clang/CodeGen/BackendUtil.h
===================================================================
--- include/clang/CodeGen/BackendUtil.h
+++ include/clang/CodeGen/BackendUtil.h
@@ -16,6 +16,7 @@
namespace llvm {
class Module;
+ class MemoryBufferRef;
}
namespace clang {
@@ -37,6 +38,9 @@
const TargetOptions &TOpts, const LangOptions &LOpts,
StringRef TDesc, llvm::Module *M, BackendAction Action,
raw_pwrite_stream *OS);
+
+ void EmbedBitcode(llvm::Module *M, const CodeGenOptions &CGOpts,
+ llvm::MemoryBufferRef Buf);
}
#endif
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