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| author | Fangrui Song <maskray@google.com> | 2024-01-11 10:24:25 -0800 |
|---|---|---|
| committer | H.J. Lu <(no_default)> | 2024-01-30 15:21:04 -0800 |
| commit | d7250100381b817114447d91fff4748526d4fb21 (patch) | |
| tree | 8ffd0604735438337ee4856ec7994a83153e167f /gcc | |
| parent | f2061b2a9641c2228d4e2d86f19532ad7e93d627 (diff) | |
| download | gcc-d7250100381b817114447d91fff4748526d4fb21.zip gcc-d7250100381b817114447d91fff4748526d4fb21.tar.gz gcc-d7250100381b817114447d91fff4748526d4fb21.tar.bz2 | |
i386: Add "Ws" constraint for symbolic address/label reference [PR105576]
Printing the raw symbol is useful in inline asm (e.g. in C++ to get the
mangled name). Similar constraints are available in other targets (e.g.
"S" for aarch64/riscv, "Cs" for m68k).
There isn't a good way for x86 yet, e.g. "i" doesn't work for
PIC/-mcmodel=large. This patch adds "Ws". Here are possible use cases:
```
namespace ns { extern int var; }
asm (".pushsection .xxx,\"aw\"; .dc.a %0; .popsection" :: "Ws"(&var));
asm (".reloc ., BFD_RELOC_NONE, %0" :: "Ws"(&var));
```
gcc/ChangeLog:
PR target/105576
* config/i386/constraints.md: Define constraint "Ws".
* doc/md.texi: Document it.
gcc/testsuite/ChangeLog:
PR target/105576
* gcc.target/i386/asm-raw-symbol.c: New testcase.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/i386/constraints.md | 4 | ||||
| -rw-r--r-- | gcc/doc/md.texi | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/i386/asm-raw-symbol.c | 13 |
3 files changed, 21 insertions, 0 deletions
diff --git a/gcc/config/i386/constraints.md b/gcc/config/i386/constraints.md index 0c6e662..280e4c8 100644 --- a/gcc/config/i386/constraints.md +++ b/gcc/config/i386/constraints.md @@ -348,6 +348,10 @@ to double word size." (match_operand 0 "x86_64_dwzext_immediate_operand")) +(define_constraint "Ws" + "A symbolic reference or label reference." + (match_code "const,symbol_ref,label_ref")) + (define_constraint "Z" "32-bit unsigned integer constant, or a symbolic reference known to fit that range (for immediate operands in zero-extending x86-64 diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi index 47a87d6..b0c6192 100644 --- a/gcc/doc/md.texi +++ b/gcc/doc/md.texi @@ -4275,6 +4275,10 @@ require non-@code{VOIDmode} immediate operands). 128-bit integer constant where both the high and low 64-bit word satisfy the @code{e} constraint. +@item Ws +A symbolic reference or label reference. +You can use the @code{%p} modifier to print the raw symbol. + @item Z 32-bit unsigned integer constant, or a symbolic reference known to fit that range (for immediate operands in zero-extending x86-64 diff --git a/gcc/testsuite/gcc.target/i386/asm-raw-symbol.c b/gcc/testsuite/gcc.target/i386/asm-raw-symbol.c new file mode 100644 index 0000000..b785456 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/asm-raw-symbol.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ + +extern int var; + +void +func (void) +{ + __asm__ ("@ %p0" : : "Ws" (func)); + __asm__ ("@ %p0" : : "Ws" (&var + 1)); +} + +/* { dg-final { scan-assembler "@ func" } } */ +/* { dg-final { scan-assembler "@ var\\+4" } } */ |