[PATCH] D72227: Add options for clang to align branches within 32B boundary

[Fangrui Song via Phabricator via cfe-commits]

MaskRay added inline comments.


================
Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2010
 
+static void AlignBranchesOptions(const Driver &D, const ArgList &Args,
+                                 ArgStringList &CmdArgs) {
----------------
The convention is `camelCase`. This file is inconsistent but some newly added functions follow this convention.


================
Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2012
+                                 ArgStringList &CmdArgs) {
+  if (const Arg *A = Args.getLastArg(options::OPT_malign_branch_boundary_EQ)) {
+    StringRef Value = A->getValue();
----------------
    if (!TC.getTriple().isX86()) {
      D.Diag(diag::err_drv_unsupported_opt_for_target)
          << A->getAsString(Args) << TripleStr;
    return;
  }

I will add Triple::isX86 in D72247.


================
Comment at: clang/lib/Driver/ToolChains/Clang.cpp:2045
+
+  if (Args.hasFlag(options::OPT_mbranches_within_32B_boundaries,
+                   options::OPT_mno_branches_within_32B_boundaries, false)) {
----------------
`OPT_mbranches_within_32B_boundaries` should provide default values which can be overridden by more specific options.


================
Comment at: clang/test/Driver/intel-align-branch.c:28
+//
+// // RUN: %clang -target x86_64-unknown-unknown -mbranches-within-32B-boundaries -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-TOTAL
+// CHECK-TOTAL: "-mllvm" "-x86-align-branch-boundary=32" "-mllvm" "-x86-align-branch=fused+jcc+jmp" "-mllvm" "-x86-align-branch-prefix-size=4"
----------------
Since you have a `-mno.. -m..` test, the `-m..` test is redundant.


================
Comment at: clang/test/Driver/intel-align-branch.c:35
+// RUN: %clang -target x86_64-unknown-unknown -mbranches-within-32B-boundaries -mno-branches-within-32B-boundaries -### -c %s 2>&1 | FileCheck %s --check-prefix=CHECK-TOTAL3
+// CHECK-TOTAL3-NOT: "-mllvm" "-x86-align-branch-boundary=32" "-mllvm" "-x86-align-branch=fused+jcc+jmp" "-mllvm" "-x86-align-branch-prefix-size=4"
----------------
Add a `-target aarch64` test that other targets will get an error.

(I am lazy and usually just write `-target x86_64` (generic ELF) and omit `-unknown-known`)


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D72227/new/

https://reviews.llvm.org/D72227