Programs with very large __llvm_covmap sections may fail to link on
Darwin because because of out-of-range 32-bit RIP relative references.
It isn't possible to work around this by using the large code model
because it isn't supported on Darwin. One solution is to move the
__llvm_covmap section past the end of the __DATA segment.
=== Testing ===
In addition to check-{llvm,clang,profile}, I performed a link test on a
simple object after injecting ~4GB of padding into __llvm_covmap:
@__llvm_coverage_padding = internal constant [
4000000000 x i8] zeroinitializer, section "__LLVM_COV,__llvm_covmap", align 8
(This test is too expensive to check-in.)
=== Backwards Compatibility ===
This patch should not pose any backwards-compatibility concerns. LLVM
is expected to scan all of the sections in a binary for __llvm_covmap,
so changing its segment shouldn't affect anything. I double-checked this
by loading coverage produced by an unpatched compiler with a patched
llvm-cov.
Suggested by Nick Kledzik.
llvm-svn: 285360
/// Return the name of the section containing function coverage mapping
/// data.
inline StringRef getInstrProfCoverageSectionName(bool AddSegment) {
- return AddSegment ? "__DATA," INSTR_PROF_COVMAP_SECT_NAME_STR
+ return AddSegment ? "__LLVM_COV," INSTR_PROF_COVMAP_SECT_NAME_STR
: INSTR_PROF_COVMAP_SECT_NAME_STR;
}
; CHECK: @foo_noinst = private global [19 x i8] c"scannerWithString:\00", section "__TEXT,__objc_methname,cstring_literals"
@.str_noinst = private unnamed_addr constant [4 x i8] c"aaa\00", section "llvm.metadata"
-@.str_noinst_prof = private unnamed_addr constant [4 x i8] c"aaa\00", section "__DATA,__llvm_covmap"
+@.str_noinst_old_cov = private unnamed_addr constant [4 x i8] c"aaa\00", section "__DATA,__llvm_covmap"
+@.str_noinst_new_cov = private unnamed_addr constant [4 x i8] c"aaa\00", section "__LLVM_COV,__llvm_covmap"
@.str_noinst_LLVM = private unnamed_addr constant [4 x i8] c"aaa\00", section "__LLVM,__not_visible"
@.str_inst = private unnamed_addr constant [4 x i8] c"aaa\00"
; CHECK-NOT: {{asan_gen.*str_noinst}}
-; CHECK-NOT: {{asan_gen.*str_noinst_prof}}
+; CHECK-NOT: {{asan_gen.*str_noinst_old_cov}}
+; CHECK-NOT: {{asan_gen.*str_noinst_new_cov}}
; CHECK-NOT: {{asan_gen.*str_noinst_LLVM}}
; CHECK: {{asan_gen.*str_inst}}
; CHECK: @asan.module_ctor