[Remarks] Emit a section containing remark diagnostics metadata
A section containing metadata on remark diagnostics will be emitted if
the flag (-mllvm) -remarks-section is present.
For now, the metadata is:
* a magic number for remarks: "REMARKS\0"
* the version number: a little-endian uint64_t
* the absolute file path to the serialized remark diagnostics: a
null-terminated string.
Differential Revision: https://reviews.llvm.org/D59571
llvm-svn: 357043
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 5319519..f467c39 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -78,6 +78,7 @@
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
+#include "llvm/IR/RemarkStreamer.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Value.h"
#include "llvm/MC/MCAsmInfo.h"
@@ -99,6 +100,7 @@
#include "llvm/MC/MCValue.h"
#include "llvm/MC/SectionKind.h"
#include "llvm/Pass.h"
+#include "llvm/Remarks/Remark.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
@@ -141,6 +143,11 @@
STATISTIC(EmittedInsts, "Number of machine instrs printed");
+static cl::opt<bool> EnableRemarksSection(
+ "remarks-section",
+ cl::desc("Emit a section containing remark diagnostics metadata"),
+ cl::init(false));
+
char AsmPrinter::ID = 0;
using gcp_map_type = DenseMap<GCStrategy *, std::unique_ptr<GCMetadataPrinter>>;
@@ -1331,6 +1338,38 @@
}
}
+void AsmPrinter::emitRemarksSection(Module &M) {
+ RemarkStreamer *RS = M.getContext().getRemarkStreamer();
+ if (!RS)
+ return;
+
+ // Switch to the right section: .remarks/__remarks.
+ MCSection *RemarksSection =
+ OutContext.getObjectFileInfo()->getRemarksSection();
+ OutStreamer->SwitchSection(RemarksSection);
+
+ // Emit the magic number.
+ OutStreamer->EmitBytes(remarks::Magic);
+ // Explicitly emit a '\0'.
+ OutStreamer->EmitIntValue(/*Value=*/0, /*Size=*/1);
+
+ // Emit the version number: little-endian uint64_t.
+ // The version number is located at the offset 0x0 in the section.
+ std::array<char, 8> Version;
+ support::endian::write64le(Version.data(), remarks::Version);
+ OutStreamer->EmitBinaryData(StringRef(Version.data(), Version.size()));
+
+ // Emit the null-terminated absolute path to the remark file.
+ // The path is located at the offset 0x4 in the section.
+ StringRef FilenameRef = RS->getFilename();
+ SmallString<128> Filename = FilenameRef;
+ sys::fs::make_absolute(Filename);
+ assert(!Filename.empty() && "The filename can't be empty.");
+ OutStreamer->EmitBytes(Filename);
+ // Explicitly emit a '\0'.
+ OutStreamer->EmitIntValue(/*Value=*/0, /*Size=*/1);
+}
+
bool AsmPrinter::doFinalization(Module &M) {
// Set the MachineFunction to nullptr so that we can catch attempted
// accesses to MF specific features at the module level and so that
@@ -1362,6 +1401,12 @@
EmitVisibility(Name, V, false);
}
+ // Emit the remarks section contents.
+ // FIXME: Figure out when is the safest time to emit this section. It should
+ // not come after debug info.
+ if (EnableRemarksSection)
+ emitRemarksSection(M);
+
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
TLOF.emitModuleMetadata(*OutStreamer, M);
diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index 1c845f6..0faa236 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -290,6 +290,9 @@
FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
0, SectionKind::getMetadata());
+ RemarksSection = Ctx->getMachOSection(
+ "__LLVM", "__remarks", MachO::S_ATTR_DEBUG, SectionKind::getMetadata());
+
TLSExtraDataSection = TLSTLVSection;
}
@@ -475,6 +478,9 @@
Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
+
+ RemarksSection =
+ Ctx->getELFSection(".remarks", ELF::SHT_PROGBITS, ELF::SHF_EXCLUDE);
}
void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {