[XRay] Merge instrumentation point table emission code into AsmPrinter.
Summary:
No need to have this per-architecture. While there, unify 32-bit ARM's
behaviour with what changed elsewhere and start function names lowercase
as per the coding standards. Individual entry emission code goes to the
entry's own class.
Fully tested on amd64, cross-builds on both ARMs and PowerPC.
Reviewers: dberris
Subscribers: aemerson, llvm-commits
Differential Revision: https://reviews.llvm.org/D28209
llvm-svn: 290858
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index de0a4f0..5f15ac1 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -37,6 +37,8 @@
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCSectionELF.h"
+#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/MCValue.h"
@@ -2610,6 +2612,61 @@
void AsmPrinterHandler::markFunctionEnd() {}
+// In the binary's "xray_instr_map" section, an array of these function entries
+// describes each instrumentation point. When XRay patches your code, the index
+// into this table will be given to your handler as a patch point identifier.
+void AsmPrinter::XRayFunctionEntry::emit(int Bytes, MCStreamer *Out,
+ const MCSymbol *CurrentFnSym) const {
+ Out->EmitSymbolValue(Sled, Bytes);
+ Out->EmitSymbolValue(CurrentFnSym, Bytes);
+ auto Kind8 = static_cast<uint8_t>(Kind);
+ Out->EmitBytes(StringRef(reinterpret_cast<const char *>(&Kind8), 1));
+ Out->EmitBytes(
+ StringRef(reinterpret_cast<const char *>(&AlwaysInstrument), 1));
+ Out->EmitZeros(2 * Bytes - 2); // Pad the previous two entries
+}
+
+void AsmPrinter::emitXRayTable() {
+ if (Sleds.empty())
+ return;
+
+ auto PrevSection = OutStreamer->getCurrentSectionOnly();
+ auto Fn = MF->getFunction();
+ MCSection *Section = nullptr;
+ if (MF->getSubtarget().getTargetTriple().isOSBinFormatELF()) {
+ if (Fn->hasComdat()) {
+ Section = OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS,
+ ELF::SHF_ALLOC | ELF::SHF_GROUP, 0,
+ Fn->getComdat()->getName());
+ } else {
+ Section = OutContext.getELFSection("xray_instr_map", ELF::SHT_PROGBITS,
+ ELF::SHF_ALLOC);
+ }
+ } else if (MF->getSubtarget().getTargetTriple().isOSBinFormatMachO()) {
+ Section = OutContext.getMachOSection("__DATA", "xray_instr_map", 0,
+ SectionKind::getReadOnlyWithRel());
+ } else {
+ llvm_unreachable("Unsupported target");
+ }
+
+ // Before we switch over, we force a reference to a label inside the
+ // xray_instr_map section. Since this function is always called just
+ // before the function's end, we assume that this is happening after
+ // the last return instruction.
+
+ auto WordSizeBytes = TM.getPointerSize();
+ MCSymbol *Tmp = OutContext.createTempSymbol("xray_synthetic_", true);
+ OutStreamer->EmitCodeAlignment(16);
+ OutStreamer->EmitSymbolValue(Tmp, WordSizeBytes, false);
+ OutStreamer->SwitchSection(Section);
+ OutStreamer->EmitLabel(Tmp);
+ for (const auto &Sled : Sleds)
+ Sled.emit(WordSizeBytes, OutStreamer.get(), CurrentFnSym);
+
+ OutStreamer->SwitchSection(PrevSection);
+ Sleds.clear();
+}
+
void AsmPrinter::recordSled(MCSymbol *Sled, const MachineInstr &MI,
SledKind Kind) {
auto Fn = MI.getParent()->getParent()->getFunction();