[MC] Add assembler support for .cg_profile.

Object FIle Representation
At codegen time this is emitted into the ELF file a pair of symbol indices and a weight. In assembly it looks like:

.cg_profile a, b, 32
.cg_profile freq, a, 11
.cg_profile freq, b, 20

When writing an ELF file these are put into a SHT_LLVM_CALL_GRAPH_PROFILE (0x6fff4c02) section as (uint32_t, uint32_t, uint64_t) tuples as (from symbol index, to symbol index, weight).

Differential Revision: https://reviews.llvm.org/D44965

llvm-svn: 333823

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/tools/llvm-readobj/llvm-readobj.cpp b/llvm/tools/llvm-readobj/llvm-readobj.cpp
index 4b8a1b32471..f871dc90950 100644
--- a/llvm/tools/llvm-readobj/llvm-readobj.cpp
+++ b/llvm/tools/llvm-readobj/llvm-readobj.cpp
@@ -284,6 +284,8 @@ namespace opts {
   cl::alias HashHistogramShort("I", cl::desc("Alias for -elf-hash-histogram"),
                                cl::aliasopt(HashHistogram));
 
+  cl::opt<bool> CGProfile("elf-cg-profile", cl::desc("Display callgraph profile section"));
+
   cl::opt<OutputStyleTy>
       Output("elf-output-style", cl::desc("Specify ELF dump style"),
              cl::values(clEnumVal(LLVM, "LLVM default style"),
@@ -441,6 +443,8 @@ static void dumpObject(const ObjectFile *Obj, ScopedPrinter &Writer) {
       Dumper->printGroupSections();
     if (opts::HashHistogram)
       Dumper->printHashHistogram();
+    if (opts::CGProfile)
+      Dumper->printCGProfile();
     if (opts::Notes)
       Dumper->printNotes();
   }