llvm-project/llvm
Heejin Ahn 49e7ee4dd5 [WebAssembly] Compare functions by names in Emscripten Sjlj
Summary:
This removes all string constants for function names and compares
functions by string directly when needed. Many of these constants are
used only once or twice so the benefit of defining them separately is
not very clear, and this actually fixes a bug.

When we already have a `malloc` declaration which is an alias to
something else within the module,
```
@malloc = weak hidden alias i8* (i32), i8* (i32)* @dlmalloc
```
(this happens compiling with emscripten with `-s WASM_OBJECT_FILES=0`
because all bc files are merged before being fed into `wasm-ld` which
runs the backend optimizations as LTO)

`Module::getFunction("malloc")` in `canLongjmp` returns `nullptr`
because `Module::getFunction` dyncasts pointer into `Function`, but the
alias is a `GlobalValue` but not a `Function`. This makes `canLongjmp`
return false for `malloc` in this case, and we end up adding a lot of
longjmp handling code around malloc. This is not only a code size
increase but actually a bug because `malloc` is used in the entry block
when preparing for setjmp tables for emscripten sjlj handling, and this
makes initial setjmp preparation, which has to happen in the entry
block, move to another split block, and this interferes with SSA update
later.

This also adds two more functions, `getTempRet0` and `setTempRet0`, in
the list of not longjmp-able functions.

Fixes https://github.com/emscripten-core/emscripten/issues/8935.

Reviewers: sbc100

Subscribers: mehdi_amini, jgravelle-google, hiraditya, sunfish, dexonsmith, dschuff, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67129

llvm-svn: 370828
2019-09-03 22:26:49 +00:00
..
benchmarks
bindings Bump llvm-go to C++14 2019-08-15 10:55:25 +00:00
cmake [cmake] Improve comment describing the C4245 warning. NFCI. 2019-09-03 16:11:37 +00:00
docs [llvm-profdata] Add mode to recover from profile read failures 2019-09-03 22:23:16 +00:00
examples [ORCv2] - New Speculate Query Implementation 2019-08-27 18:23:36 +00:00
include [InstrProf] Tighten a check for malformed data records in raw profiles 2019-09-03 22:23:14 +00:00
lib [WebAssembly] Compare functions by names in Emscripten Sjlj 2019-09-03 22:26:49 +00:00
projects [libc++] Take 2: Integrate the PSTL into libc++ 2019-08-05 18:29:14 +00:00
resources
runtimes
test [WebAssembly] Compare functions by names in Emscripten Sjlj 2019-09-03 22:26:49 +00:00
tools [llvm-profdata] Add mode to recover from profile read failures 2019-09-03 22:23:16 +00:00
unittests Skip MCJIT unit tests if LLVM is not configured for native compilation 2019-09-03 19:30:45 +00:00
utils gn build: (manually) merge r370499 2019-09-03 13:17:16 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitattributes
.gitignore
CMakeLists.txt Revert Autogenerate the shebang lines for tools/opt-viewer 2019-08-27 18:31:29 +00:00
CODE_OWNERS.TXT
CREDITS.TXT
LICENSE.TXT
LLVMBuild.txt
README.txt
RELEASE_TESTERS.TXT
configure
llvm.spec.in

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