| Message ID | 20210513133754.753762-1-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Warn for excessive argument alignment in main | expand |
On 5/13/21 3:37 PM, H.J. Lu via Gcc-patches wrote: > Warn for excessive argument alignment in main instead of ICE. > > gcc/ > > PR c/100575 > * cfgexpand.c (expand_stack_alignment): Add a bool argument for > expanding main. Warn for excessive argument alignment in main. > (pass_expand::execute): Pass true to expand_stack_alignment when > expanding main. > > gcc/testsuite/ > > PR c/100575 > * c-c++-common/pr100575.c: New test. > --- > gcc/cfgexpand.c | 26 ++++++++++++++++++++------ > gcc/testsuite/c-c++-common/pr100575.c | 11 +++++++++++ > 2 files changed, 31 insertions(+), 6 deletions(-) > create mode 100644 gcc/testsuite/c-c++-common/pr100575.c > > diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c > index e3814ee9d06..50ccb720e6c 100644 > --- a/gcc/cfgexpand.c > +++ b/gcc/cfgexpand.c > @@ -6363,7 +6363,7 @@ discover_nonconstant_array_refs (void) > virtual_incoming_args_rtx with the virtual register. */ > > static void > -expand_stack_alignment (void) > +expand_stack_alignment (bool expanding_main) > { > rtx drap_rtx; > unsigned int preferred_stack_boundary; > @@ -6385,9 +6385,18 @@ expand_stack_alignment (void) > if (targetm.calls.update_stack_boundary) > targetm.calls.update_stack_boundary (); > > - /* The incoming stack frame has to be aligned at least at > - parm_stack_boundary. */ > - gcc_assert (crtl->parm_stack_boundary <= INCOMING_STACK_BOUNDARY); > + if (crtl->parm_stack_boundary > INCOMING_STACK_BOUNDARY) > + { > + /* The incoming stack frame has to be aligned at least at > + parm_stack_boundary. NB: The incoming stack frame alignment > + for main is fixed. */ > + if (expanding_main) > + warning_at (DECL_SOURCE_LOCATION (current_function_decl), > + OPT_Wmain, "argument alignment of %q+D is too large", > + current_function_decl); > + else > + gcc_unreachable (); > + } Could you do this instead in ix86_minimum_incoming_stack_boundary /* The incoming stack frame has to be aligned at least at parm_stack_boundary. */ if (incoming_stack_boundary < crtl->parm_stack_boundary) incoming_stack_boundary = crtl->parm_stack_boundary; /* Stack at entrance of main is aligned by runtime. We use the smallest incoming stack boundary. */ if (incoming_stack_boundary > MAIN_STACK_BOUNDARY && DECL_NAME (current_function_decl) && MAIN_NAME_P (DECL_NAME (current_function_decl)) && DECL_FILE_SCOPE_P (current_function_decl)) incoming_stack_boundary = MAIN_STACK_BOUNDARY; maybe just repeat this after incoming_stack_boundary is set to MAIN_STACK_BOUNDARY: /* The incoming stack frame has to be aligned at least at parm_stack_boundary. */ if (incoming_stack_boundary < crtl->parm_stack_boundary) incoming_stack_boundary = crtl->parm_stack_boundary; and print the warning here? Thanks Bernd.
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c index e3814ee9d06..50ccb720e6c 100644 --- a/gcc/cfgexpand.c +++ b/gcc/cfgexpand.c @@ -6363,7 +6363,7 @@ discover_nonconstant_array_refs (void) virtual_incoming_args_rtx with the virtual register. */ static void -expand_stack_alignment (void) +expand_stack_alignment (bool expanding_main) { rtx drap_rtx; unsigned int preferred_stack_boundary; @@ -6385,9 +6385,18 @@ expand_stack_alignment (void) if (targetm.calls.update_stack_boundary) targetm.calls.update_stack_boundary (); - /* The incoming stack frame has to be aligned at least at - parm_stack_boundary. */ - gcc_assert (crtl->parm_stack_boundary <= INCOMING_STACK_BOUNDARY); + if (crtl->parm_stack_boundary > INCOMING_STACK_BOUNDARY) + { + /* The incoming stack frame has to be aligned at least at + parm_stack_boundary. NB: The incoming stack frame alignment + for main is fixed. */ + if (expanding_main) + warning_at (DECL_SOURCE_LOCATION (current_function_decl), + OPT_Wmain, "argument alignment of %q+D is too large", + current_function_decl); + else + gcc_unreachable (); + } /* Update crtl->stack_alignment_estimated and use it later to align stack. We check PREFERRED_STACK_BOUNDARY if there may be non-call @@ -6699,12 +6708,17 @@ pass_expand::execute (function *fun) } } + bool expanding_main = false; + /* If this function is `main', emit a call to `__main' to run global initializers, etc. */ if (DECL_NAME (current_function_decl) && MAIN_NAME_P (DECL_NAME (current_function_decl)) && DECL_FILE_SCOPE_P (current_function_decl)) - expand_main_function (); + { + expanding_main = true; + expand_main_function (); + } /* Initialize the stack_protect_guard field. This must happen after the call to __main (if any) so that the external decl is initialized. */ @@ -6847,7 +6861,7 @@ pass_expand::execute (function *fun) /* Call expand_stack_alignment after finishing all updates to crtl->preferred_stack_boundary. */ - expand_stack_alignment (); + expand_stack_alignment (expanding_main); /* Fixup REG_EQUIV notes in the prologue if there are tailcalls in this function. */ diff --git a/gcc/testsuite/c-c++-common/pr100575.c b/gcc/testsuite/c-c++-common/pr100575.c new file mode 100644 index 00000000000..e7366a8fe7f --- /dev/null +++ b/gcc/testsuite/c-c++-common/pr100575.c @@ -0,0 +1,11 @@ +/* { dg-do run } */ +/* { dg-options "-Wall -Wno-psabi" } */ + +int +main (int __attribute__((vector_size(1 << 29))) argc, + char **argv) +/* { dg-warning "first argument of" "" { target *-*-* } .-2 } */ +/* { dg-warning "argument alignment of" "" { target *-*-* } .-3 } */ +{ + return 0; +}