[PATCH] D154121: [BOLT][Instrumentation] Fix indirect call profile in PIE

[Denis Revunov via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGa86dd9ae6066: [BOLT][Instrumentation] Fix indirect call profile in PIE (authored by treapster).
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

Changed prior to commit:
  https://reviews.llvm.org/D154121?vs=544704&id=552877#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D154121/new/

https://reviews.llvm.org/D154121

Files:
  bolt/lib/Rewrite/RewriteInstance.cpp
  bolt/runtime/common.h
  bolt/runtime/instr.cpp


Index: bolt/runtime/instr.cpp
===================================================================
--- bolt/runtime/instr.cpp
+++ bolt/runtime/instr.cpp
@@ -215,6 +215,12 @@
 /// __bolt_instr_setup, our initialization routine.
 BumpPtrAllocator *GlobalAlloc;
 
+// Base address which we substract from recorded PC values when searching for
+// indirect call description entries. Needed because indCall descriptions are
+// mapped read-only and contain static addresses. Initialized in
+// __bolt_instr_setup.
+uint64_t TextBaseAddress = 0;
+
 // Storage for GlobalAlloc which can be shared if not using
 // instrumentation-file-append-pid.
 void *GlobalMetadataStorage;
@@ -1389,7 +1395,7 @@
   const IndCallDescription *CallsiteDesc =
       &Ctx->IndCallDescriptions[CallsiteID];
   const IndCallTargetDescription *TargetDesc =
-      Ctx->lookupIndCallTarget(Entry.Key);
+      Ctx->lookupIndCallTarget(Entry.Key - TextBaseAddress);
   if (!TargetDesc) {
     DEBUG(report("Failed to lookup indirect call target\n"));
     char LineBuf[BufSize];
@@ -1609,6 +1615,7 @@
 extern "C" void __attribute((force_align_arg_pointer)) __bolt_instr_setup() {
   __bolt_ind_call_counter_func_pointer = __bolt_instr_indirect_call;
   __bolt_ind_tailcall_counter_func_pointer = __bolt_instr_indirect_tailcall;
+  TextBaseAddress = getTextBaseAddress();
 
   const uint64_t CountersStart =
       reinterpret_cast<uint64_t>(&__bolt_instr_locations[0]);
Index: bolt/runtime/common.h
===================================================================
--- bolt/runtime/common.h
+++ bolt/runtime/common.h
@@ -165,6 +165,20 @@
 // Anonymous namespace covering everything but our library entry point
 namespace {
 
+// Get the difference between runtime addrress of .text section and
+// static address in section header table. Can be extracted from arbitrary
+// pc value recorded at runtime to get the corresponding static address, which
+// in turn can be used to search for indirect call description. Needed because
+// indirect call descriptions are read-only non-relocatable data.
+uint64_t getTextBaseAddress() {
+  uint64_t DynAddr;
+  uint64_t StaticAddr;
+  __asm__ volatile("leaq __hot_end(%%rip), %0\n\t"
+                   "movabsq $__hot_end, %1\n\t"
+                   : "=r"(DynAddr), "=r"(StaticAddr));
+  return DynAddr - StaticAddr;
+}
+
 constexpr uint32_t BufSize = 10240;
 
 #define _STRINGIFY(x) #x
Index: bolt/lib/Rewrite/RewriteInstance.cpp
===================================================================
--- bolt/lib/Rewrite/RewriteInstance.cpp
+++ bolt/lib/Rewrite/RewriteInstance.cpp
@@ -1845,8 +1845,9 @@
     exit(1);
   }
 
-  if (opts::ReorderFunctions != ReorderFunctions::RT_NONE &&
-      !opts::HotText.getNumOccurrences()) {
+  if (opts::Instrument ||
+      (opts::ReorderFunctions != ReorderFunctions::RT_NONE &&
+       !opts::HotText.getNumOccurrences())) {
     opts::HotText = true;
   } else if (opts::HotText && !BC->HasRelocations) {
     errs() << "BOLT-WARNING: hot text is disabled in non-relocation mode\n";


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