[PATCH] D58548: IR: Support parsing numeric block ids, and emit them in textual output.

[James Y Knight via Phabricator via cfe-commits]

jyknight created this revision.
jyknight added a reviewer: philip.pfaffe.
Herald added subscribers: cfe-commits, jdoerfert, jfb, dexonsmith, steven_wu, hiraditya, mehdi_amini.
Herald added projects: clang, LLVM.

Just as as llvm IR supports explicitly specifying numeric value ids
for instructions, and emits them by default in textual output, now do
the same for blocks.

This is a slightly incompatible change in the textual IR format.

Previously, llvm would parse numeric labels as string names. E.g.

  define void @f() {
    br label %"55"
  55:
    ret void
  }

defined a label *named* "55", even without needing to be quoted, while
the reference required quoting. Now, if you intend a block label which
looks like a value number to be a name, you must quote it in the
definition too (e.g. `"55":`).

Previously, llvm would print nameless blocks only as a comment, and
would omit it if there was no predecessor. This could cause confusion
for readers of the IR, just as unnamed instructions did prior to the
addition of "%5 = " syntax, back in 2008 (PR2480).

Now, it will always print a label for an unnamed block, with the
exception of the entry block. (IMO it may be better to print it for
the entry-block as well. However, that requires updating many more
tests.)

Thus, the following is supported, and is the canonical printing:

  define i32 @f(i32, i32) {
    %3 = add i32 %0, %1
    br label %4
  
  4:
    ret i32 %3
  }

New test cases covering this behavior are added, and other tests
updated as required.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D58548

Files:
  clang/test/CodeGenCXX/discard-name-values.cpp
  llgo/test/irgen/imports.go
  llvm/lib/AsmParser/LLLexer.cpp
  llvm/lib/AsmParser/LLParser.cpp
  llvm/lib/AsmParser/LLParser.h
  llvm/lib/AsmParser/LLToken.h
  llvm/lib/IR/AsmWriter.cpp
  llvm/test/Analysis/DominanceFrontier/new_pm_test.ll
  llvm/test/Analysis/RegionInfo/cond_loop.ll
  llvm/test/Analysis/RegionInfo/condition_forward_edge.ll
  llvm/test/Analysis/RegionInfo/condition_same_exit.ll
  llvm/test/Analysis/RegionInfo/condition_simple.ll
  llvm/test/Analysis/RegionInfo/infinite_loop.ll
  llvm/test/Analysis/RegionInfo/infinite_loop_2.ll
  llvm/test/Analysis/RegionInfo/infinite_loop_3.ll
  llvm/test/Analysis/RegionInfo/infinite_loop_4.ll
  llvm/test/Analysis/RegionInfo/infinite_loop_5_a.ll
  llvm/test/Analysis/RegionInfo/infinite_loop_5_b.ll
  llvm/test/Analysis/RegionInfo/infinite_loop_5_c.ll
  llvm/test/Analysis/RegionInfo/loop_with_condition.ll
  llvm/test/Analysis/RegionInfo/mix_1.ll
  llvm/test/Analysis/RegionInfo/paper.ll
  llvm/test/Assembler/block-labels.ll
  llvm/test/Assembler/invalid-block-label-num.ll
  llvm/test/CodeGen/X86/atomic-pointer.ll
  llvm/test/Instrumentation/AddressSanitizer/asan-masked-load-store.ll
  llvm/test/Instrumentation/AddressSanitizer/stack-poisoning-and-lifetime-be.ll
  llvm/test/Instrumentation/AddressSanitizer/stack-poisoning-and-lifetime.ll
  llvm/test/Instrumentation/AddressSanitizer/stack_dynamic_alloca.ll
  llvm/test/Instrumentation/MemorySanitizer/check_access_address.ll
  llvm/test/Instrumentation/MemorySanitizer/msan_basic.ll
  llvm/test/Instrumentation/MemorySanitizer/msan_kernel_basic.ll
  llvm/test/Instrumentation/MemorySanitizer/msan_x86_bts_asm.ll
  llvm/test/Instrumentation/MemorySanitizer/store-origin.ll
  llvm/test/Instrumentation/SanitizerCoverage/stack-depth.ll
  llvm/test/Transforms/GVNHoist/pr36787.ll
  llvm/test/Transforms/LowerSwitch/2014-06-23-PHIlowering.ll

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